Evaluation of new shipping technology for Australian vegetables

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1 Evaluation of new shipping technology for Australian vegetables Jenny Ekman NSW Department of Primary Industries Project Number: VG04020

2 VG04020 This report is published by Horticulture Australia Ltd to pass on information concerning horticultural research and development undertaken for the vegetable industry. The research contained in this report was funded by Horticulture Australia Ltd with the financial support of the vegetable industry. All expressions of opinion are not to be regarded as expressing the opinion of Horticulture Australia Ltd or any authority of the Australian Government. The Company and the Australian Government accept no responsibility for any of the opinions or the accuracy of the information contained in this report and readers should rely upon their own enquiries in making decisions concerning their own interests. ISBN Published and distributed by: Horticulture Australia Ltd Level 1, 50 Carrington Street Sydney NSW 2000 T: (02) F: (02) E: info@horticulture.com.au Copyright 2006

3 Horticulture Australia project VG Final Report submitted January, 2006 Dr Jenny Ekman NSW Department of Primary Industries

4 VG Key Personnel Dr Jenny Ekman - NSW DPI (Project Leader) Dr John Golding - NSW DPI Dr Nick Smale - Food Science Australia Dr Dave Tanner - Food Science Australia This report details the results of initial storage trials of broccoli, cauliflower and lettuce. This was followed by a trial shipment of these products to Dubai and a parallel static trial simulating the same voyage. The project examined the effect of packaging method, storage temperature and storage atmosphere on outturn quality and shelf life following shipping. The viability of exporting vegetables by sea to distant markets is discussed. January 2006 Funding for this work was provided by Any recommendations contained in this publication do not necessarily represent current HAL Limited policy. No person should act on the basis of the contents of this publication, whether as to matters of fact or opinion or other content, without first obtaining specific, independent professional advice in respect of the matters set out in this publication.

5 Contents Contents... 1 Media Summary... 2 Technical Summary... 3 Abbreviations... 4 Introduction... 5 Shipping technology... 5 Export markets - Dubai... 6 Vegetable storage life - Review... 7 Broccoli... 7 Cauliflower... 8 Lettuce... 8 Project aims... 9 Initial Static Storage Trial Introduction Materials and Methods Results Results Broccoli quality Cauliflowers Lettuce Discussion and Conclusions Broccoli Cauliflower Lettuce Static and Live Shipments Introduction Materials and Methods Obtaining the shipping containers Harvest Initial quality evaluations Loading the containers Statistical analysis Results Temperatures during the trial...28 Gas concentrations during the trial Product quality evaluations Broccoli quality Cauliflower quality Lettuce quality Lettuce quality Financial analysis Discussion and key points...48 Technology Transfer Recommendations References Attachments Attachment 1 - Grading scales Attachment 2 - Air delivery and return temperatures Attachment 2 - Air delivery and return temperatures Attachment 3 - Cargo temperatures Attachment 4 - Contour plots showing spatial temperature profiles Temperatures during shipping to Dubai Temperatures during static trial

6 Media Summary This project has examined the potential for shipping broccoli, cauliflower and lettuce to distant export markets. Initial storage experiments in the laboratory were followed by a full scale static trial at the Food Science Australia container testing facility and an actual shipment of two 6m containers to Dubai. Key conclusions from the initial work were; Broccoli could be stored for up to 3 weeks in ice, 4 weeks in air alone or 5 weeks in atmospheres containing 10%O %CO 2 or 2%O 2 + 2%CO 2 and still have acceptable quality and shelf life under retail conditions Cauliflowers were still acceptable after 5 weeks as long as water loss was minimised Lettuce quality after 3-4 weeks was variable; storage life depends on initial quality. The full scale static trial and live shipments compared outturn quality and shelf life between a standard and a modified atmosphere (MA) shipping container. This technology uses respiration of the stored product to increase CO 2 and decrease O 2 inside the container, potentially increasing storage life. A number of different packaging treatments were also trialled. Products were stored for 23 days at -0.5 o C in the static trial and 26 days at +0.5 o C (air) or -0.5 o C (MA) in the live shipment. Key findings were; Temperature variability within the stow was reduced by setting the temperature above 0 o C or limiting the rate of air exchange All of the static trial products were in generally acceptable condition at outturn. The Dubai importers considered all of the broccoli to be in good condition on arrival. The cauliflowers were acceptable and the lettuces were in variable to poor condition. Broccoli packed in ice had significantly more rots and discolouration and developed more off odours than any other packaging method. CSIRO s moisture control technology (MCT) liners reduced stem scar discolouration. Modifying the storage atmosphere using the MA container system or Lifespan bags did not significantly improve broccoli quality compared to air storage with a plastic liner. Cauliflowers stored under MA at -0.5 o C suffered less curd blackening and softening than those stored under air in +0.5 o C. Tissue wraps resulted in greater weight loss and did not reduce curd blackening compared to plastic bags. Lettuces developed soft rots and pink rib during storage. Pink rib was strongly related to physical damage. Soft rots may have been increased by heavy rain one week before harvest. The results suggest that it is physically and economically possible to use sea freight to ship Australian vegetables to Dubai. Profitability could be increased by shipping in 12m instead of 6m containers. 2

7 Technical Summary Exports of Australian vegetables decreased by approximately 30% between , due primarily to increased competition in our traditional Asian markets. Markets in the Middle East appear to have potential, but have previously been accessed only by air freight. Sea freight has cost and volume advantages, but products must arrive in good condition with adequate shelf life. This project has examined the feasibility of exporting broccoli, cauliflower and lettuce to Dubai by sea using new storage technologies and packaging methods. Initial laboratory scale storage experiments were conducted to determine maximum storage time at 0.5 o C for broccoli, cauliflower and lettuces held under different atmospheres. Quality attributes were evaluated at outturn and following 2 days at 20 o C. Key results were; Broccoli could be stored for up to 3 weeks in ice, 4 weeks in air alone or 5 weeks in atmospheres containing 10%O %CO 2 or 2%O 2 + 2%CO 2 and still have acceptable quality and shelf life under retail conditions Cauliflowers held under high RH were still acceptable after 5 weeks in air Lettuce quality after 3-4 weeks was variable; storage life is likely to depend on initial quality. These experiments were followed by a full scale static trial at the Food Science Australia container testing facility and a parallel live shipment to Dubai. Each trial compared a standard and a modified atmosphere (MA) 6m reefer container. An AFAM+ container was used for the live shipment, while the AFAM s operation was replicated using a standard reefer and external control systems in the static trial. A number of packaging treatments were also trialled. Products were stored for 23 days at -0.5 o C in the static trial and 26 days at +0.5 o C (air) or -0.5 o C (MA) in the live shipment. Temperature was mapped intensively throughout the container stows. Quality was evaluated at outturn and following 2 days shelf life. Key results were; Reducing evaporator frosting minimised temperature variability within the stows. Variability was greatest in the standard static container due to its relatively high rate of air exchange and setpoint <0 o C. Mean air delivery temperature in the static MA container was -0.9 o C, which could have damaged products susceptible to freezing injury. Neither of the MA containers reached the 10%CO 2 setpoint. This was primarily due to leakage from the containers. In the case of the AFAM+, the significant discrepancy (~4%) between the CO 2 sensor/controller and other O 2 and CO 2 sensors used contributed to this result. All of the static trial products were in generally acceptable condition at outturn. The Dubai importers considered all of the broccoli to be in good condition on arrival. The cauliflowers were acceptable although pre-harvest curd yellowing was an issue. The lettuces were in variable condition due to bacterial soft rots and pink rib disorder and were repacked before sale. Broccoli packed in ice had significantly more rots and stem scar discolouration and developed more off odours than any other packaging method. CSIRO s new moisture control technology (MCT) liners reduced stem scar discolouration but did not affect other attributes. Modifying the storage atmosphere using either the MA shipping container or Lifespan bags in air did not significantly improve broccoli quality compared to air storage with a plastic liner. Measured ethylene was below detectable levels, so ethylene control sachets in packages had no effect on quality. Cauliflowers stored under MA at -0.5 o C suffered less curd blackening and softening than those stored in air at +0.5 o C. Tissue wraps increased weight loss and did not reduce curd blackening compared to individual plastic bags. Pink rib on lettuces was strongly related to physical damage and symptoms increased during shelf life. Soft rot development may have been increased by heavy rain one week before harvest. Broccoli shipped in the AFAM+ did not gain higher prices in the Dubai market. It is concluded that the potential benefits of using the AFAM+ system were not realised given the relatively short shipping time and low temperatures used. A small nett profit was gained for the Dubai shipment, but a considerable loss incurred by the static trial, due largely to low returns in an oversupplied Sydney market. The results suggest that it is physically and economically possible to use regular sea freight to ship Australian vegetables to Dubai. Profitability could be increased by shipping in 12m containers. 3

8 Abbreviations AFAM+ CA FSA LDPE Lifespan HP Advanced fresh air management (MA container developed by ThermoKing) controlled atmosphere (O 2 decreased and/or CO 2 increased by gas flushing and control) Food Science Australia low density polyethylene film, used for packaging High permeability Lifespan bag, designed by Amcor for higher storage temperatures encountered during transport Lifespan LP Low permeability Lifespan bag, designed by Amcor for storage temperatures o C MA MCT NSW DPI Reefer RH modified atmosphere (O 2 decreased and CO 2 increased by product respiration) Moisture control technology, a liner developed by CSIRO to maintain high humidity while avoiding free water condensing on products NSW Department of Primary Industries Refrigerated shipping container relative humidity 4

9 Introduction Vegetables are exported from Australia using both air and sea freight. Sea freight has traditionally been used for relatively closer destinations in Asia, such as Japan, Singapore and Hong Kong while more distant destinations such as the Middle East, Europe and the USA have been accessed by air. However, the high cost of airfreight has meant that only limited volumes of high value products could be transported in this way. Exports of Australian vegetables have decreased significantly in the last few years (Table 1). The primary reason for this is increased competition, especially from China. In some cases, Chinese grown products are sold for less than Australian products cost to produce. Intense price based competition, the higher A$, increased transport costs and difficult growing conditions within Australia have combined to push Australian vegetables out of our traditional Asian markets. Product Exports ($million) Major markets in 2002 Carrots Malaysia, Singapore, Hong Kong, Japan Cauliflower, broccoli Malaysia, Singapore Leafy greens Hong Kong, Malaysia, Japan Sweet corn Japan, New Zealand Celery Malaysia, Taiwan, Hong Kong, Singapore Table 1 - Changes in value of exports for some Australian vegetable crops. Data from ABS. The Australian vegetable industry needs to develop new and existing markets outside of the Asian region if they are to halt or even reverse this trend. However, the relatively high cost of airfreight for vegetables has made this difficult. While sea freight is significantly cheaper than airfreight (approximately half price, depending on weight and volume), transit times were thought to be too long for products to arrive in good condition and with acceptable shelf life. This situation is now changing. Ship transit times have been significantly reduced with faster boats and better connections. New harvesting, cooling and packaging systems and storage technology can allow products to be stored longer in better condition. Combining these factors may make it possible for Australian vegetables to be shipped by sea into distant markets. Shipping technology Refrigerated containers (reefers) are more reliable and easily available than ever before. Modern shipping containers have bottom air, rather than passive top air delivery. Cold air is delivered through T-bar shaped channels in the floor, forced upwards through the load and recycled through the air return at the top of the plenum area. This means that, so long as the load is properly precooled and the floor completely covered, there is no need to leave gaps between pallets. Some shipping containers have controlled atmosphere (CA) systems installed. CA systems control the concentrations of oxygen (O 2 ) and carbon dioxide (CO 2 ) inside the container. Such atmospheres can extend storage life of certain products by reducing product respiration, decreasing sensitivity to ethylene gas and reducing growth of fungi and bacteria. The atmosphere inside the container is modified using bottled supplies of gases or, in newer containers, using an on-board nitrogen generation system. Many of these containers also humidify the air, as adding nitrogen alone to the storage atmosphere necessarily decreases relative humidity. The main 5

10 disadvantages with using CA systems are their cost, availability in Australia and the restriction to 12m (40 ) containers (there are no 6m - 20 CA containers). In the last few years modified atmosphere (MA) systems have become available. These systems allow product respiration to build up CO 2 and deplete O 2 inside the container. Gas sensors control the ventilation, adding enough fresh air to keep CO 2 just below a maximum setpoint. Although such systems can provide only a limited range of atmospheres they are simpler and therefore potentially cheaper than CA systems. They also maintain high humidity inside the load and are available with 6m or 12m containers. Three types of MA containers are now available in Australia the ThermoKing AFAM, the Mitsubishi MaxTend and the Transfresh Tectrol. The ThermoKing AFAM+ system is integrated into the container itself. In contrast, the Mitsubishi MaxTend and TransFresh systems consist of a removable unit which can be fitted onto any reasonably gas tight shipping container. Another difference is that passive respiration alone is used to modify the atmosphere inside the AFAM+. The MaxTend is usually flushed with nitrogen after loading, and bags of lime may be added to reduce CO 2 buildup. For MA shipping of Australian vegetables to be feasible, the cost of using the units must be justified by improved quality and/or shelf life at the export destination. However, there is little or no information comparing the outturn quality of products shipped in MA units or conventional systems. There is also little information on the relationship between time and outturn quality for different systems; many trials have a single removal time, making it difficult to draw conclusions about longer or shorter shipping times. Finally, existing recommendations usually assume a mixed load within a container. However, Australian exporters may need to ship mixed loads due to the logistics involved in both filling and selling containers with single commodities. This project was developed to examine the feasibility and effectiveness of different shipping technologies for exporting mixed loads of Australian vegetables. Export markets - Dubai In this project we have primarily targeted Dubai, one of the seven Emirates that make up the UAE (United Arab Emirates), as a potential market for Australian vegetables transported by sea freight. Dubai itself has little oil, although much of the wealth of the surrounding Emirates comes from this source. It was originally settled as a small trading port and fishing village at the mouth of Dubai creek. The area s growth started in 1966 when oil was struck in Abu Dhabi. The city has undergone incredible expansion over the last 10 years, a trend which appears set to continue and even accelerate. Around $4 million people live in the UAE, over 1.5million of whom are based in Dubai. Approximately 80% of the population are expatriates. Dubai has few taxes, no exchange controls or quotas, few quarantine restrictions, is politically stable and is now serviced by more than 170 shipping lines and 85 airlines. A current housing shortage is being addressed with massive residential developments spreading along the coast of the Persian Gulf. Tourism is also expanding. Dubai is famous as the site of the world s only 7-star hotel the Burj Al- Arab. The city currently has 400 hotels, with many new resorts and hotels being built along the coasts. In million people visited Dubai, adding over A$2 billion to the cities revenues. Hotels are often booked out over the popular winter months, with 81% occupancy rates on average. The city is currently developing a massive indoor ski run, billion dollar shopping malls, theme parks, the Global Village and the famous Palm and The World land reclamation 6

11 projects. The World Trade Organisation predicts that 15 million tourists will be visiting annually by Dubai is a hub for much of the trade, business activity and investment in the entire Middle East. Imports have more than doubled over the last 10 years. There is not only a growing market within the UAE itself, but also in the surrounding areas that it services. In July 2005, the Government forecast economic growth of 12.7% for the next 12 months. While this may seem overoptimistic, the last few years have commonly seen annual growth of approximately 10%. The food service market alone is estimated as worth US$300 million. Much of this market is for top quality products to be used by restaurants and hotels. There is also a large and expanding supermarket sector. This is currently dominated by Carrefour, which has set up a number of hypermarkets which sell consumer goods as well as groceries and fresh products. Dubai therefore represents a promising opportunity for Australian horticultural exporters ready to supply this burgeoning market. Australia is well placed due to its reputation for good quality products and some good relationships with businesses already operating in Dubai. Vegetable storage life - Review It was planned that we would export high quality broccoli, cauliflower and lettuce to Dubai. The viability of this plan was checked against the storage lives of these products as reported in the literature. According to often quoted University of California, Davis postharvest resources, potential storage life at 0 o C is; Broccoli days Cauliflower 3-4 weeks Lettuce 2-3 weeks Broccoli Broccoli high respiration rate and susceptibility to moisture loss mean it can be extremely perishable. At harvest broccoli florets can lose 1% of their mass per hour simply to respiration (Pogson and Morris, 1997). Storage life is maximised using rapid cooling and storage at -1-0 o C. Broccoli is usually packed in ice, which keeps it well hydrated and cool during handling and transport (Shewfelt et al., 1983). Although icing is not necessary if the cool chain and RH can be maintained (Kleiber et al, 1993), it is often used commercially because of client expectations and perceived enhancement of appearance. Many studies determine the end of broccoli storage life according to yellowing of the florets. This process is mediated by ethylene and can occur rapidly (2 days) at ambient temperatures. However, at low storage temperatures (<5 o C) ethylene has less effect and storage life is usually ended by rots. Some studies have reported that broccoli lasts much more than 2 weeks at close to 0 o C. For example, broccoli was still acceptable following 5 weeks at 1 o C (Pogson and Morris, 1997) and 7-8 weeks at 0 o C (Shewfelt et al, 1983, Klieber and Wills, 1991). Optimal atmospheres (1-2.5%O %CO 2 ) can greatly increase storage life when broccoli is held at temperatures above 5 o C (Makhlouf et al., 1989). In some cases storage life may be doubled due to the reduction of ethylene production, decreased ethylene sensitivity, reduced respiration and inhibition of decay. More than 10% CO 2 or less than 1% O 2 are not usually recommended because of increased off odours. Off odours can develop in atmospheres containing 5-10% CO 2, but disperse reasonably quickly when the product is transferred to air. The effects of CA are generally much less at the low temperatures normally used for storage. However, CA may still offer some benefits during long term storage. For example, CA extended storage life of broccoli florets from 5 to 7 weeks at 4 o C (Bastrash et al, 1993) and improved outturn 7

12 quality of broccoli stored at 1 o C for four weeks (Makhlouf et al., 1989). CA storage for less than 3 weeks may have little or no effect on outturn quality or subsequent shelf life (Ballantyne et al, 1988). Cauliflower Cauliflowers are mainly composed of delicate curds which are vulnerable to damage during harvest and postharvest handling. Damaged areas may be more likely to develop rots as well as the black spotting of the curds which is the main cause of postharvest quality loss. The exact causes of black spotting are unclear. It appears to be caused primarily by fungal infection, mainly Alternaria spp. but also Rhizopus and Botrytis (Menniti and Casalini, 2000, Snowden, 1991). Saprophytic bacteria such as Pseudomonas spp. may also be involved (Amariutei et al, 1977). Physiological disorders can also cause spotting, and the condition may be increased by bruising, prolonged wetness and over maturity of the head (Wilkinson and Tomkins, 199_). Even though cauliflower is a major crop, a review of the literature indicates that little has been published on storage life and quality of this vegetable for nearly 30 years. Mertens and Tranggono (1989) found that shelf life was unaffected by storage at 0-1 o C for 4 weeks, and only slightly reduced when cauliflowers were stored for 6 weeks. It is usually recommended that cauliflower should not be stored in greater than 5% CO 2 due to the development of stem injury and off odours and flavours. These may not be detectable immediately after storage but develop when the curds are cooked. This effect was first reported by Lipton and Harris (1976) and subsequently by Menniti and Casalini (2000). However, normal aeration after storage reduces this effect (Tomkins and Sutherland, 1989) A review of the potential for MA storage of cauliflower by Wilkinson and Tomkins (199_) concluded that storage in 4-6% CO 2 and 2-3% O 2 could extend cauliflower storage life to 7 weeks at 0 o C. Higher concentrations of CO 2 can help control bacterial rots, although they may cause a transient CO 2 injury which should disappear during marketing. However, maturity is a critical factor and there are likely to be differences between varieties. Lettuce Lettuce is highly susceptible to freezing so although optimum shelf life is achieved at 0 o C, it is usually stored at 0.5 o C or higher. Head lettuces (iceberg types) keep better than the loose-leafed varieties usually grown hydroponically, and storage life may be up to 1 month with ideal handling. Storage life is often ended by the appearance of bacterial or fungal soft rots (Wilkinson et al., 1995). Physiological disorders including russetting (caused by exposure to ethylene), brown stain (high CO 2 injury), pink rib and heart leaf browning also cause significant losses. Head lettuce is susceptible to damage from >2%CO 2, particularly when combined with low oxygen concentrations. The damage may not be obvious on removal from storage, but develop during marketing (Stewart and Uota, 1971, Ke and Saltveit, 1989). Up to 5% CO 2 may be tolerated by some varieties for shorter storage times. Curiously, 10% CO 2 is recommended for cut lettuce as it inhibits browning of the cut surfaces and brown stain is less of an issue (Smyth et al., 1998). Low oxygen atmospheres can maintain lettuce quality during long term storage by reducing decay, preserving colour and potentially reducing the incidence of pink rib disorder (Haginuma et al, 1985, Martinez and Artes, 1999). The usual atmosphere recommended is 2-3%O 2 + 2%CO 2. Modified atmosphere systems are generally unable to reduce O 2 to this level without building up damaging levels of CO 2, so may not be useful for storage of lettuce. 8

13 Project aims Surprisingly little research has focussed on the relationships between time, storage atmosphere and quality of vegetables. In particular, industry needs to know the conditions which are most appropriate for a particular length of shipping time; establishment of a modified atmosphere may be the difference between acceptable and unacceptable outturn for a distant destination, but an unnecessary expense for one closer to home. This project has attempted to clarify how produce quality changes over time and following long term storage. The aim of this project was to test the effectiveness of modified atmosphere shipping containers compared to standard shipping containers for exporting Australian vegetables. The original plan was to conduct small scale trial examining storage life of various vegetables under different storage atmospheres. This was to be followed by a full scale static trial comparing different types of shipping containers using the Food Science Australia container test facility at North Ryde. The trial would allow detailed temperature mapping of the conditions inside the containers during a simulated export. This information could then be linked with outturn quality of the products. Discussions and close collaboration between the NSW DPI project team and Fresh Select, Werribee made it possible to add an extra component an actual trial shipment, to be conducted in parallel with the static trial. The shipment was to be conducted by Fresh Select using their understanding of the export process, contacts and experience to examine the commercial effects of the treatments. This addition to the original project was discussed with the project steering committee. At a meeting attended by representatives from AusVeg, HAL, NSW DPI, Food Science Australia and Fresh Select it was agreed that this would add value to the existing project. It was recommended that we conduct a trial shipment to Dubai in addition to the static trial. This document details the results of the; 1. Initial static storage trial at Gosford 2. Full scale shipping simulation at Food Science Australia s container test facility, North Ryde 3. Live shipment of two containers to Dubai. 9

14 Initial Static Storage Trial Introduction The first step in developing a sea freight export program for Australian vegetables was to determine the limits of storage life under various atmospheric conditions. In particular, we were interested in outturn quality following storage times approximating those required for transport to Dubai. The main options for shipping to Dubai appeared to be; Standard refrigerated container Modified atmosphere container Controlled atmosphere container As lettuce, broccoli and cauliflower had been nominated as the focus of this project, we wanted to examine how quality changed during low temperature storage under these alternative treatments and following two days of simulated shelf life at 20 o C. The modified atmosphere recommended for broccoli has been reported to cause damage for cauliflower and lettuce. This could atmosphere could still be used within a mixed shipment with Amcor Lifespan modified atmosphere (MA) packaging. These microperforated bags are designed to provide an atmosphere of approximately 11%O %CO 2 similar to that achievable in an MA shipping container. In this trial we compared a low oxygen controlled atmosphere (CA) which was potentially suitable for all three products (2%O 2 + 2%CO 2 ) with storage in air or under MA. 10

15 Materials and Methods Broccoli, cauliflower and lettuce were shipped overnight from Werribee, Victoria to the NSW DPI laboratory at Gosford. Broccoli and cauliflower were in excellent condition, having been harvested within the previous 24 hours. The lettuces had been harvested at least 2 days earlier and were in good / average condition. Broccoli was removed from crushed ice and spread out to dry in the laboratory. The heads were randomised into 64 groups of 4 heads. Each of the four heads was numbered, weighed and colour was recorded using a chroma meter (Minolta CR-400, pulsed xenon lamp, average of 3 readings / head). Outer leaves were removed and bases re-trimmed on the cauliflowers and lettuce (Figure 1). Each product was randomised into 48 groups of three heads. The cauliflowers were numbered, weighed and colour recorded with the chroma-meter. Lettuces were not numbered, but weighed as a unit. Each product unit was packed into a perforated plastic bag and placed under MA, CA or air. To achieve the storage atmospheres, products were placed in sealed steel drums with the gas mixture flowing through them. To check that this in itself was not affecting quality, additional products were stored in still air in the cool room. The treatments are summarised as; Broccoli MA - 10%O %CO 2 CA - 2%O 2 + 2%CO 2 Air - flow through system Air - static, product packed in ice Cauliflower CA - 2%O 2 + 2%CO 2 Air - flow through system Air - static, product in cartons in the cool room Lettuce CA - 2%O 2 + 2%CO 2 Air - flow through system Air - static, product in cartons in the cool room Replication was achieved using four separate drums / cartons for each product. Each contained four treatment units of broccoli, cauliflower or lettuce. One unit was removed from each drum or carton after 21, 28, 35 or 42 days of storage at 0.3 o C. Colour, weight loss and quality attributes were assessed immediately, then again following 2 days shelf life at 20 o C and 60-79% relative humidity. Subjective assessments were made using standard scales (Attachment 1). Results were subjected to analysis of variance (ANOVA) using CoStat statistical software (CoHort Software, California). Differences were determined using the Student-Newman-Keuls test at the p=0.05 significance level. Figure 1 - Dr John Golding examines lettuce quality during trimming and repacking 11

16 Results Broccoli quality Colour Broccoli yellowed significantly with storage time. Differences were small when the broccoli was initially removed from cold storage but increased following storage for 2 days at 20 o C. The measured hue angle of MA stored broccoli was statistically significantly lower (indicating yellowing) than the other treatments following 2 days shelf life. However, this difference was not discernible and would not be commercially significant. Weight loss and firmness Weight loss measurements on ice packed broccoli were invalid due to ice and water clinging to the heads. Weight loss of heads stored in air, CA or MA increased significantly after 5 weeks storage, but still remained less than 2% for most individual heads. Broccoli stored under MA lost significantly more weight than those stored in air or CA during 2 days shelf life. Subjective measurements of firmness indicated that ice stored broccoli was significantly firmer after storage than other treatments, and retained this quality during shelf life. Odour No unpleasant odours were detected after 3 weeks storage for any of the treatments. Odours increased with length of storage after this time, particularly in the broccoli stored under MA (Figure 2). Ice stored broccoli also became increasingly smelly, especially when stored for 6 weeks. However, although odours decreased during shelf life for broccoli stored under MA, odours increased in the ice stored broccoli. This meant that broccoli stored under MA smelt worse than ice packed product when removed from storage, but after 2 days this was reversed. Broccoli in CA or air smelled significantly less than the other treatments. 3 Odour 2 1 Air Ice CA MA Storage time (days) Figure 2 - Odour of broccoli heads immediately after storage at 0.3 o C in air ( ), ice ( ), 2%O 2 +2%CO 2 ( ) or 10%O 2 +10%CO 2 ( ), then again following 2 days shelf life in air at 20 o C (broken lines). Mean values (n=16) are from 0-nil off odour to 3-moderate offensive off odour 12

17 Rots and stem scar discolouration Storage in ice significantly increased the incidence of rots (Figure 3, 4). There were less rots in MA storage than in ice, but more than in CA or air. The scars where leaves had been removed from the stems developed more blackening during storage in ice than other methods (Figure 5). After two days at 20 o C, the order of severity of blackening was ice>air>ca>ma, all differences being significant. Figure 3 - Ice packed broccoli showing extensive rots 3 Rots in stem or florets 2 1 Air Ice CA MA Storage time (days) Figure 4 - Incidence of rots on broccoli heads immediately after storage at 0.3 o C in air ( ), ice ( ), 2%O 2 +2%CO 2 ( ) or 10%O 2 +10%CO 2 ( ), then again following 2 days shelf life in air at 20 o C (broken lines). Mean values (n=16) are from 0-nil to 3-moderate 3 Stem scar discolouration Air 2 Ice CA MA Storage time (days) Figure 5 - Discolouration of the stem scars of broccoli heads immediately after storage at 0.3 o C in air ( ), ice ( ), 2%O 2 +2%CO 2 ( ) or 10%O 2 +10%CO 2 ( ), then again following 2 days shelf life in air at 20 o C (broken lines). Mean values (n=16) are from 0-nil to 3-dark brown/grey 13

18 Overall quality Ice packed broccoli was consistently ranked as lower quality overall than the other treatments when storage time was greater than 28 days. Deterioration of this product was most obvious after 2 days shelf life, when yellowing, floret rots, odour and stem discolouration meant these heads were in very poor condition (Figure 6). 4 3 Quality 2 1 Air Ice CA MA Storage time (days) Figure 6 - Broccoli quality grades immediately after storage at 0.3 o C in air ( ), ice ( ), 2%O 2 +2%CO 2 ( ) or 10%O 2 +10%CO 2 ( ), then again following 2 days shelf life in air at 20 o C (broken lines). Mean values (n=16) are from 0-nil to 3-dark brown/grey 14

19 Cauliflowers Weight loss and firmness Weight loss during storage was significantly reduced by CA compared to either air storage in the flow through system or static air storage in a carton. However, this difference disappeared during shelf life. All of the cauliflowers remained firm for the duration of the trial, with only minor softening even after 2 days at 20 o C. Quality and colour Measurements made with the chroma meter were not found to be a good indicator of cauliflower quality. Although L-values (brightness, whiteness) changed over time, changes were inconsistent and variable and no significant differences were found between the treatments. Colour and quality were also evaluated in terms of the surface area affected by black spotting of the curds. The appearance of discoloured spots and marks on the cauliflowers increased with length of storage and accelerated once the cauliflowers were placed at 20 o C for two days (Figure 7). CA storage significantly improved appearance when the cauliflowers were cold stored for more than four weeks. However, this difference disappeared during shelf life. The limit of saleability was considered to be black spotting = 2, meaning that the limit of storage life was 4 weeks. 4 Black spotting air box CA Storage time (days) Figure 7 - Appearance of discoloured spots on cauliflowers immediately after storage at 0.3 o C in flow through air ( ), static air ( ), or flow through 2%O 2 +2%CO 2 ( ), then again following 2 days shelf life in air at 20 o C (broken lines). Mean values (n=12) are from 0-nil to 4-severe 15

20 Lettuce Lettuce quality and incidence of rots were evaluated after removing the two outer leaves from each head, both at the initial evaluation and following two days shelf life at 20 o C. It was felt this reflected retailer / consumer behaviour. As a result, quality of some heads appeared to improve between the first and second evaluations. No real differences were observed between any of the treatments (Figure 8). The incidence of rots did not appear to greatly increase at initial outturns between 21 and 42 days, although lettuces stored for longer did develop more rots during shelf life. Overall quality deteriorated with length of storage. However, this data was highly variable, some heads having advanced rots or pink rib disorder, while others remained in good condition. Given a limit in saleability of quality = 2 (fair condition), the results suggest that it may be possible to store lettuce for up to 4 weeks, long enough to allow transport to Dubai. 4 3 Quality 2 1 air box CA Storage time (days) Figure 8 - Overall quality of crisphead lettuces immediately after storage at 0.3 o C in flow through air ( ), static air ( ), or flow through 2%O 2 +2%CO 2 ( ), then again following 2 days shelf life in air at 20 o C (broken lines). Mean values (n=12) are from 4-excellent to 0-inedible 16

21 Discussion and Conclusions Broccoli Overall, the best atmosphere for keeping broccoli was found to be CA; 2%O 2 +2%CO 2. Although MA (10%O 2 +10%CO 2 ) gave excellent control of stem scar discolouration, it resulted in offensive odours at outturn and increased rots during subsequent shelf life. Broccoli stored in air alone yellowed more than that in MA or CA. Packing in ice increased rots and odour and decreased quality compared to other treatments, especially after removal to 20 o C. Some of this effect may be due to melting of the ice during storage; the storage temperature should have been <0 o C to ensure ice remained frozen, but was higher to accommodate lettuce in the same room. Also, broccoli had warmed up during initial sorting and then been repacked into crushed ice. From discussions with industry it appears that the major reasons broccoli is exported in ice are to maintain cold temperatures during transport and storage and because this meets the presentation standards expected by clients. Many in the industry are aware that CA / MA can provide better outturn after long term storage than packing in ice. Although it is difficult to change long term practices and expectations, the benefits of not icing during long term storage and transport would seem significant. Based on these results, ice stored broccoli could be stored for a maximum of 3 weeks, air stored broccoli for 4 weeks, and CA or MA stored broccoli for 5 weeks. After 6 weeks storage and 2 days shelf life none of the broccoli was in saleable or even edible condition. As shipping time to Dubai is 3-4 weeks, it would appear either air alone, MA or CA storage would be suitable for transport of broccoli to this market. Packing in ice seems less likely to give acceptable outturn quality. Cauliflower Cauliflower quality was only very marginally improved by CA storage after 5 weeks storage. It is concluded that cauliflowers stored in air should still be in acceptable condition after transport to Dubai so long as moisture loss is minimised. Lettuce Lettuce is the product most likely to suffer problems during transport to a market such as Dubai. The quality of lettuce evaluated during this trial was highly variable. Quality issues resulted from pink rib disorder, soft rots and wilting. CA storage did not improve storability or shelf life of lettuce in this case. Given a shipping time of 3-4 weeks it seems possible that lettuce can be shipped in air to Dubai. However, acceptability is likely to depend on the initial quality of the product and its microbial load, as well as the markets tolerance for product variability. 17

22 Static and Live Shipments Introduction The shipping trial was conducted during July August As the trial was an opportunity to test a number of new technologies, several other companies became involved and provided materials for the project free of charge; SudChemie markets a range of ethylene absorbers. These are individual sachets as well as larger units which can be placed over the return air vents in a shipping container. The company supplied several hundred sachets and 4 larger scrubbers for use in the trial (Figure 9). Figure 9 ethylene removing filter supplied by SudChemie Amcor markets a range of Lifespan modified atmosphere packaging films, including two carton liners for broccoli; one is designed for long term storage at 0-2 o C, the other for the higher temperatures often encountered during transport and marketing. Samples of these were provided and used with broccoli in the standard reefer. The atmosphere generated inside these bags was aimed to be approximately equivalent to that generated inside the AFAM+. CSIRO is in the process of commercialising a new type of packaging, called Moisture Control Technology (MCT). This packaging provides high humidity while avoiding free moisture condensing on the product. Trials have been conducted with cauliflowers and citrus, with promising results. We were unable to use this packaging for cauliflowers because of intellectual property issues, but could trial the liners with lettuce and broccoli. 18

23 Materials and Methods Obtaining the shipping containers Complications arose early in the planning process because the different shipping companies who operate from Australia vary in requirements regarding the containers used. For example, an AFAM+ container can be shipped using Pacific Asia Express (PAE), but not by Maersk. PAE does not permit either the MaxTend or the TransFresh units to be fitted onto their containers as they see this as competition with the AFAM+ system. Maersk does not carry any MA container systems because they are promoting use of their own CA containers. Clearly we could not organise the containers until we settled on a shipping company. While Maersk has a good reputation with perishables, in this case its prices were higher and shipping times longer than PAE, so we agreed to use the latter company. We had planned to use a Mitsubishi MaxTend as well as an AFAM+ (Advanced Fresh Air Management) during the trial so that we could compare the effectiveness of the two systems. Both containers were to be set to provide atmospheres of up to 10%CO 2 which was considered optimal for broccoli. Fortunately, PAE agreed to allow fitting of a MaxTend system to their container for the static trial for scientific purposes. However, Mitsubishi MaxTend were not happy with this experimental plan. Their recommended atmosphere for broccoli is 15%CO 2 + 5%O 2. Oxygen is initially lowered by flushing the container with nitrogen. The CO 2 concentration can be reduced if necessary using CO 2 scrubbers. The initial fitting of the unit was to be done in Brisbane, then a technician would travel to Gatton to complete the installation and flush the container with Nitrogen. Travel of the technician and flushing the container added $2,000 to the $1,500 hire fee. In contrast, the AFAM+ units simply control the gas atmosphere inside the container through modulation of the fresh air exchange vent based on CO 2 concentration. Using an AFAM+ added a US$250 surcharge to the normal container hire charge. We could not reach agreement with MaxTend on this issue; we wanted to compare operation directly with an AFAM+, but the company felt that this did not demonstrate the full benefits of using the MaxTend system. They regard the MaxTend as more like a CA system than the simple MA system used by the AFAM+. As a result, they withdrew from the trial. We were able to source one AFAM+ and three standard reefers from PAE/PIL (Figure 10). One standard reefer in the static trial could be controlled externally to simulate the operation of the AFAM+ system. The containers were tested for leaks by the Food Science Australia team before loading with product. Figure 10 - The AFAM+ and standard reefer containers arrive at Koala Farms, Gatton. 19

24 Harvest The containers were stuffed at Koala Farms, Gatton, Queensland. The property is operated by Anthony and Dianne Staatz, both of whom were enthusiastic collaborators and became further involved in the project. Anthony has been involved in developing a new commercial harvesting aid for vegetables. This device reduces the risk of impact damage occurring during harvesting. It is designed to allow single step handling and rapid transport to the cooling facility. These measures optimise the potential storage life of the products, potentially facilitating sea freight to distant markets. In this project, the machine was used to harvest and pack lettuces and cauliflowers. (a) (b) (c) (d) Figure 11 - Cauliflowers are cut and stripped (a), packed in a mobile packing shed pulled through the field by the tractor (b), palletised and taken back to the central cool store (c) where they are forced air cooled (d). The operation of the machine is shown in Figure 11. Lettuces, cauliflowers or other products are cut and trimmed in the field then placed in rubberised baskets (Fig. 11a). These transport the products to a mobile packing shed where they are wrapped and packed (Fig. 11b), palletised and taken back to the packing shed (Fig. 11c) for forced air cooling (Fig. 11d). This avoids impact damage, minimises handling and ensures products are cooled as quickly as possible after harvest. 20

25 All the product was originally planned to come from properties in the Gatton District. Unfortunately, heavy rains and flooding the week before the planned shipment severely affected much of the local broccoli crop. The shipment was delayed a week, but it became evident that broccoli would have to be sourced elsewhere. Broccoli was eventually sourced from Werribee, Victoria, and trucked to Gatton for the trial. 21

26 Initial quality evaluations A number of different packaging treatments were trialled. The experimental design is summarised in Table 1. The broccoli was packed into cardboard cartons - no styrofoam was used. As these cartons were not designed to cope with wet conditions, plastic liners were used inside iced cartons. Other broccoli was repacked into perforated plastic liners and moisture control technology (MCT) liners. Two types of Lifespan bags were tested. One was a bag designed for long term storage at 0-2 o C, the other was a more permeable bag designed for 2-7 o C, temperatures encountered during transport and handling. Ethylene scrubbing sachets were included in all of the test cartons of broccoli sent to Dubai but only some of the cartons used for the static trial (Figure 12). Cauliflower was either wrapped individually in tissue, as is normal commercial practice for export markets, or individually bagged in perforated low density polyethylene (LDPE) (Figure 12). We were not able to test MCT liners for the cauliflowers due to restrictions on its use for this purpose. No such restriction applied to lettuce, so it was packed into the MCT carton liners as well as individual LDPE bags. Container Broccoli Cauliflower Lettuce SHIPMENT TO DUBAI Plastic liner + ice AFAM+ Plastic liner MCT liner Lifespan LP* LDPE bags LDPE bags Air Lifespan HP** Tissue wraps MCT liner MCT liner STATIC TRIAL Plastic liner + ice LDPE bags MA Plastic liner MCT liner Plastic liner + ice LDPE bags Plastic liner Tissue wraps Air MCT liner Lifespan LP + filter # Lifespan LP no filter Table 1 - Contents of shipping containers. * Lifespan LP = low permeability Lifespan bags designed for long term storage at 0-2 o C ** Lifespan HP = high permeability Lifespan bags designed for transport at 2-7 o C # filter = ethylene scrubbing sachet supplied by SudChemie. Note: all bags sent to Dubai contained a sachet 22

27 a b c d Figure 12 - Some of the packaging treatments tested; MCT liner with ethylene scrubbing sachet (a), Lifespan bags with ethylene scrubbing sachet (b), ice (c) and LDPE bags (d) Twelve cartons of each treatment for each container were prepared and labelled (Figure 13). Colour of heads of broccoli and cauliflower were recorded using a Minolta colour meter. Five heads of cauliflower/carton were individually weighed and numbered. Broccoli (except iced broccoli) and lettuces were weighed on a per carton basis. a b Figure 13 - Cartons of broccoli are repacked (a) and colour measured (b) 23

28 Loading the containers Following testing by Food Science Australia, the containers were hand stacked with product in a bulk stow configuration (i.e., not palletised, no spacers used for airflow through the stack). This allowed more efficient loading of the containers and ensured that the floor was covered (essential for even airflow from the bottom air delivery system). It also avoided the need for pallets, which would have to be non-standard size to fit the container efficiently and plastic or treated to avoid quarantine issues. The details of the containers used are shown in Table 2. Table 2 - Details of 4 x 6m containers used for trial shipments Manufacturer SHIPMENT TO DUBAI Refrigeration unit Model Date in service Setpoint ( o C) Fresh air exchange rate MA setting Defrost interval AFAM+ ThermoKing CSR40SL / m 3 /h N/A 6 hours Air ThermoKing CSR40SL / N/A 10% CO 2 6 hours STATIC TRIAL MA Carrier 69NT / m 3 /h N/A 12 hours Air Daikin LXE10E-A21 01/ N/A 10% CO 2 12 hours Temperatures were measured in each of the containers using Type-T thermocouples and Eltek squirrel data loggers (1000 series, Eltek Ltd., Cambridge, UK; accuracy ±0.4 o C). Seven sensors were positioned across the air delivery, five across the air return grill and two through the door to measure ambient temperature. Cargo temperatures were measured by placing thermocouples in the cartons adjacent to hand-holes. Cargo temperature was measured in five to seven slices, with 16 sensors positioned in each slice according to the pattern shown in Figure 14. -top -floor Figure 14 - Approximate locations of thermocouples (shaded boxes) measuring cargo temperatures in a single slice of stacked cartons inside a container Relative humidity was measured in one position in each container using a TinyTag data logger (Gemini Data Loggers Ltd., UK; accuracy ±0.2 o C ±3% RH) placed adjacent to the ceiling near the door end of the container. 24

29 Gas conditions in the air containers were monitored using O 2 sensors (KE-25, Figaro, USA Inc.) connected to Tiny Tag data loggers (TGPR-1001, Gemini Data Loggers Ltd., UK; accuracy ±1mV). The two MA containers were monitored using O 2 sensors (KE-25) and a CO 2 sensor (2001VTC- Mini, SenseAir, Sweden, accuracy ±0.4% vol) with a squirrel data logger (1000 series, Eltek Ltd, Cambridge, UK; accuracy 0-5V ± 5mV / 0-50mV ±50μV). The CO 2 concentration and RH inside the AFAM+ container were also monitored by the on-board atmosphere control system. Each of the labelled sample cartons was fitted with a thermocouple so that the temperature profile could be related to outturn quality (Figure 15). The sample cartons were arranged as randomly as possible through the shipping containers (given the constraints of packing products in different sized cartons within the container). The layout of the standard reefer shipped to Dubai is shown in Figure 16. The AFAM+ shipped to Dubai contained only broccoli, while the two static containers were mainly broccoli with a slice of cauliflower cartons in the centre of each container. Figure 15 - Dr Dave Tanner and Dr Nick Smale (FSA) installing thermocouples in the cartons to monitor temperature. Thermocouples were connected to Eltek Squirrel data loggers (inset) 25

30 a b c Cooling system Cooling system Cooling system Figure 16 - Configurations of cartons of cauliflower broccoli and lettuce inside shipping containers; (a) Air to Dubai, (b) AFAM+ to Dubai, (c) both MA and Air in static trial. Following loading and instrumentation, the AFAM+ and one standard reefer were taken to Brisbane Port for loading onto the Pacific Asia Express (PAE) ship Delores, which departed on July 15 th for Singapore. The two other standard reefers were transported on-power to the Food Science Australia container test facility at North Ryde, Sydney, NSW. One of the containers used for the static trial was to be used to generate a modified atmosphere. The fresh air exchange vent on this container was closed and a CO 2 sensor (2001VTC-Mini) positioned on top of the cartons near the door end of the container. On arrival at North Ryde, the container was connected to a compressed air supply. This was activated if the CO 2 concentration inside the container reached 10%. In this fashion, the conventional container effectively functioned in the same manner as an AFAM+ container. Transit conditions expected during a voyage to Dubai in July were modelled using software developed at Food Science Australia (VoyageSim) which predicts ambient temperatures and humidity during transport from historical weather data. The static trial containers were held in a chamber in which temperature and humidity were controlled according to this model. Solar radiation was simulated using a bank of lights, as shown in Figure 17. The voyage began on 15 th July. Figure 17 - Lights inside CSIRO container test facility 26

31 Statistical analysis The effect of the 3 storage methods on broccoli quality was modelled using a mixed linear regression approach (Searle 1971) which allowed for the separation of variance into fixed and random effects. Analysis of the data was conducted in ASReml (Gilmour et al. 1998) with a fixed effect of treatment and with carton, slice and layer included as random effects. This means that carton, slice and layer represent any randomly chosen carton, slice or layer in the population of interest. Further analysis of the broccoli data as well as the cauliflower and lettuce data was conducted using CoStat statistical software. Fixed effects were examined for significance and treatment means were compared using the least significance difference (LSD) technique at the 5% level. The significance of each random term was determined by comparing twice the change in the loglikelihood (d) with a χ 2 1 statistic. Where the random terms were not significant they were omitted from the model. Total degree days were calculated for each of the marked sample cartons by multiplying the output of the relevant thermocouple by storage duration. 27

32 Results Temperatures during the trial Total product storage times were 22 days and 26 days for the static trial and live shipments respectively. The journey from Brisbane to Dubai took a total of 23 days (Figure 18). This included trans-shipment in Singapore, which resulted in a delay of approximately 1.5 days. Dubai The Kota Jasa Singapore The Delores Brisbane Figure 18 - Map of the route taken between Brisbane and Dubai The ambient temperatures generated by VoyageSim for the static trial closely matched those encountered during the actual shipment to Dubai (Figure 19) Port Brisbane Arrival in Singapore Arrival in Dubai Ambient temperature ( o C) Live shipment Static trial 0 11-Jul 18-Jul 25-Jul 1-Aug 8-Aug Figure 19 - Ambient temperatures encountered during the live shipment to Dubai ( ) and generated during the static trial simulation at North Ryde ( ). The air delivery and return temperatures in all of the containers generally remained close to the setpoints during transport apart from brief temperature spikes when the containers were off power. 28

33 (Figure 20, 21, Table 3). Temperatures were relatively constant across the width (Attachment 2) and length (Attachment 4) of the containers 20 Arrive Singapore Arrive Dubai Temperature ( o C) AFAM+ delivery AFAM+ return AIR delivery AIR return Depart Singapore Jul 18-Jul 25-Jul 01-Aug 08-Aug Figure 20 - Mean temperatures measured at the air delivery and air returns of the AFAM+ and standard air containers during shipping to Dubai Temperature ( o C) MA delivery MA return AIR delivery AIR return Jul 18-Jul 25-Jul 01-Aug 08-Aug Figure 21 - Mean temperatures measured at the air delivery and air returns of the MA and standard air containers during the static trial at North Ryde The temperatures inside the static MA container were approximately 0.6 o C cooler than those in the standard air container (Figure 21, Table 3). Both containers had the same setpoints, contents and external environment, so this difference is most likely to be due to incorrect calibration or positioning of the container control probe. Although delivery air temperature in the static MA container averaged -0.9 o C, 22% of measurements were below -1 o C, the temperature at which freezing damage can occur. While no freezing injury was observed in this trial, damage could have occurred with a more susceptible crop. 29

34 Table 3 - Setpoints, mean air delivery and mean air return temperatures measured inside containers during live and static shipping trials. Container Setpoint ( o C) Air delivery (average o C) Air return (average o C) Dubai AFAM Air Static MA Air The air delivery temperatures in the static air container show a saw tooth pattern, with the difference between maximum and minimum increasing as the temperature drops (Figure 22). This is due to frosting of the evaporator. This pattern did not occur in any of the other containers. The live air container was set at above 0 o C and had a shorter defrost interval (6 hours) than the static air container (12 hours). The MA and AFAM+ containers had minimal fresh air exchange, which also reduces frosting Temperature ( o C) Mean Minimum Maximum Jul 23-Jul 25-Jul 27-Jul Figure 22 - Detail of maximum, minimum and average temperatures inside the static air container. The saw tooth pattern and diverging maximum - minimum values is typically the result of evaporator frosting. Temperatures measured within the bulk stow inside each container were generally close to those required. More than 80% of all temperature measurements were within 1 o C of the set-point. Changes in temperature within the bulk stow over time are shown in Attachment 4. 30

35 a. 6 5 Mean Min Max Temperature ( o C) Jul 18-Jul 25-Jul 01-Aug 08-Aug b. 6 5 Mean Min Max Temperature ( o C) Jul 15-Jul 19-Jul 23-Jul 27-Jul 31-Jul 04-Aug 08-Aug Figure 23 - Maximum, minimum and average temperatures of broccoli during shipping to Dubai in an AFAM+ container (a) or standard container in air (b). There were two short off-power incidents which affected the live shipment on 26 th and 27 th of July. These occurred during trans-shipment of the containers in Singapore, but had only transitory effect on the temperature of the broccoli inside the containers (Figure 23). The shipment sent to Dubai in a standard reefer container had the least variability in temperature of all the containers used in the trial. This is primarily because it had been set at +0.5 o C to accommodate lettuce, whereas the other containers were at -0.5 o C. The higher temperature reduced frosting of the evaporator coils, improving temperature consistency within the load. This temperature variability is detailed in Attachment 3, which shows the frequency with which each temperature was recorded during shipping. 31

36 Temperature variability was greatest in the static air container (Attachment 3). Like the two MA containers, the static air container had a setpoint of -0.5 o C. However, the fresh air vent was closed on the MA containers but set at 10m 3 /h on the air container. Greater fresh air circulation increased frosting and, therefore, temperature variability. Warm air regions developed in containers in the upper levels near the door during the simulated sea voyage (Attachment 4). These warm regions reflect measurements made in cartons which were close to the walls of the container, which can experience significant heat loads from the external environment. Temperatures in these cartons are likely to increase during the journey as the ambient temperature increases and ice inside the cartons melts (Figure 24). a. 6 5 Mean Minimum Maximum 4 Temperature ( o C) Jul 18-Jul 25-Jul 01-Aug 08-Aug b. 6 5 Mean Minimum Maximum 4 Temperature ( o C) Jul 18-Jul 25-Jul 01-Aug 08-Aug Figure 24 - Product maximum, minimum and average temperatures during simulated shipping inside static containers in air (a) or MA (b). 32

37 Gas concentrations during the trial Gas concentrations inside the AFAM+ container were monitored using the on-board vent control equipment as well as additional O 2 and CO 2 sensors (Figure 25). A substantial discrepancy exists between the CO 2 concentrations recorded by the on-board equipment and the SenseAir CO 2 sensor. While the two readings run in parallel, the CO 2 controller consistently reads ~4% higher. So long as respiration is aerobic, the combined concentrations of O 2 and CO 2 should equal approximately 21%. The measured O 2 concentrations therefore support the SenseAir values ( = 21). It is worrying that the controller sensor appears to be nearly 4% out of calibration. Under different circumstances this could result in atmospheres damaging to the product, or loss of effectiveness of the AFAM+ system. Neither of the modified atmosphere containers reached the CO 2 concentration setpoint of 10%. In the case of the AFAM+, this was partly due to incorrect calibration of the CO 2 sensor. It also appears that a breach occurred during transhipment in Singapore, as the CO 2 concentration declined during the second half of the trip. The static MA container was not vented at all during storage, yet the atmosphere only reached around 8% CO 2 (Figure 26). Calculations indicate that a leakage rate of 0.6 m 3 /h would maintain this concentration assuming the container was loaded with 5 tonnes broccoli producing 10 ml CO 2 /kg.h Concentration (%) Jul 18-Jul 25-Jul 1-Aug 8-Aug AFAM+ CO2 AFAM+ O2 Air O2 AFAM+ CO2 (controller) Figure 25 - Gas concentrations inside the AFAM+ and air containers shipped to Dubai 33

38 25 20 Concentration (%) Jul 18-Jul 25-Jul 1-Aug 8-Aug MA CO2 MA O2 Air O2 Figure 26 - Gas concentrations inside the MA and air containers used in the static trial. Gas samples were taken from the Lifespan bags in Dubai before the bags were opened (Figure 27). Ethylene levels in the bags were below 0.1ppm the lowest concentration considered to be physiologically active. The CO 2 concentrations averaged 4.2% in the low permeability and 3.3% in the higher permeability Lifespan bags. These values are below the target concentration of 7-10%CO 2, but would be expected to have some physiological effect. The values may have been lower because the bags were designed for 10kg broccoli, but many contained kg. Figure 27 Sampling gases from inside Lifespan bags using Sensidyne gas detector tubes and a Kitagawa sampling pump. 34

39 Product quality evaluations As the static and live shipments were conducted simultaneously, the duration of the static trial was shortened compared to the actual shipment so as to facilitate outturn assessments in Sydney and Dubai. The static trial containers were opened on 3 rd August, 22 days after loading. Sample cartons were kept for examination and the remainder of the shipment sent to Sydney Markets for sale. The broccoli and cauliflowers were evaluated immediately on removal and again following 2 days at 20 o C. The standard air container sent to Dubai was delivered to Ghulam Ali Abdulla Trading s cool storage facility (Figure 28) late on 6 th August. The AFAM+ arrived at Shokri Hassan Trading s cool stores the following morning. The products were examined on 7 th August, 26 days after loading. Marked products were examined immediately then again after two days shelf life (9 th August). All other products were immediately sent to market for sale. The outturn of the containers in Dubai was attended by; Anthony and Dianne Staatz, Koala Farms John Said, Fresh Select, Werribee John Golding, NSW DPI Jenny Ekman, NSW DPI Figure 28 - Opening the standard air container at Ghulam Trading's cold stores, 6 th August 2005 In Dubai, 20 o C space was not available for the shelf life part of the trial at either of the two importers. Products were stored in the closest conditions available and the temperatures monitored using LogTag (Model TRIX-8, accuracy 0.5 o C) temperature recorders (Figure 29). Mean temperature during the two days of shelf life of the broccoli, cauliflowers and lettuce shipped in air (Ghulam) was 15 o C and that of the broccoli shipped under MA (Shokri) was13 o C. 35

40 30 o Temperature ( C) Ghoulam Shokri Time from start of 'shelf life' Figure 29 - Temperatures during simulated shelf life of broccoli, cauliflower and lettuce in Dubai. 36

41 Broccoli quality No strong odours were noted when either of the containers were opened and all of the broccoli was considered to be in generally acceptable condition (Figure 30, 31). Excess broccoli from the static trial was successfully sold in the Sydney Market. Both importers in Dubai were very happy with the quality of the broccoli and were able to sell it immediately through their marketing channels (Figure 30). a b Figure 30 Outturn quality of broccoli in Dubai packed in Air + MCT liner (a) or Lifespan (b) a b c d e f Figure 31 - Outturn quality of broccoli from static trial packed in MA + plastic liner (a), MA + MCT (b), MA + ice (c), Air + plastic liner (d), Air + low permeability Lifespan (e), Air + ice (f) There were significant differences between the containers as well as among the packaging treatments. All quality attributes decreased significantly during 2 days of shelf life. Differences between individual treatments were similar at out-turn and after shelf life, so only data from the 37

42 second evaluation is shown here. The differences between the packaging treatments inside each container after two days of shelf life are summarised in Table 4. Table 4 - Colour measurements and quality scores for broccoli stored under MA or in air in the live and static trials. Values are means from evaluation following storage + 2 days at approx. 20 o C. Subjective assessments were done using standard scales shown in Attachment 1. Letters indicate values which are significantly different (p<0.05) within the same shipping container. Treatment Hue o Yellowing Stem rots INITIAL VALUES DUBAI SHIPMENT Stem scar discolour Floret rots Softening Odour AFAM Ice + plastic a 1.4 a 1.1 a 2.0 a 1.0 a 0.2 b 0.9 a Plastic liner* a 1.3 a 0.2 b 1.2 b 0.1 b 1.1 a 0.1 b MCT liner* a 1.3 a 0.1 b 1.0 b 0.2 b 1.1 a 0.1 b Air Lifespan HP* b 1.8 a 0.2 a 1.6 a 0.4 a 1.2 b 0.1 a STATIC TRIAL Lifespan LP* b 1.8 a 0.0 a 2.0 a 0.4 a 1.2 b 0.2 a MCT liner* a 1.8 a 0.0 a 1.2 b 0.5 a 1.5 a 0.1 a MA Ice + plastic a 1.5 b 0.9 a 2.6 a 1.1 a 2.0 a 2.2 a Plastic liner c 2.9 a 0.3 b 1.6 b 0.5 b 1.6 b 1.8 b MCT liner b 2.4 a 0.1 b 1.4 c 0.2 c 1.4 c 1.1 c Air Ice + plastic a 1.7 c 1.4 a 2.7 a 1.4 a 1.6 a 2.2 a Plastic d 2.6 a 0.2 c 1.4 bc 0.8 b 1.6 a 1.8 b MCT liner c 2.7 a 0.3 c 1.3 c 0.2 c 1.4 a 0.9 d Lifespan LP* b 2.3 b 0.6 b 1.7 b 0.6 bc 1.7 a 1.1 d Lifespan LP c 2.3 b 0.3 c 1.7 b 0.6 bc 1.7 a 1.5 c * Ethylene filter included in bag Weight loss during storage was not affected by packaging treatment and was less than 1% for all broccoli stored in air. Weight loss was significantly greater for the broccoli stored under MA, but remained less than 3% in most cartons and did not affect overall quality. The content of the storage atmosphere did not affect colour of the broccoli heads according to either the subjective assessments of yellowing or the objective measurements of hue o. This is most likely related to the relatively short storage times (<4 weeks) and low temperatures used. There did not to be any effect of using ethylene control filters in the packages, probably because ethylene production was minimal. Ethylene was below physiologically active concentrations in all of the packages tested. The filters may have had more effect if storage conditions had been more demanding. It was noted that wetting the ethylene filters dissolved the enclosed potassium permanganate, resulting in purple, stains (Figure 32). 38 Figure 32 - A wet ethylene filter leaking potassium permanganate

43 Packing in ice consistently resulted in more stem rots, floret rots, stem scar discolouration and odour than the other packaging methods (Figure 33). Although ice maintained firmness better in the AFAM+ container, this difference was not found during the static trial. Although the treatments were coded so that the evaluator did not know the packaging treatment of each sample, it was easy to tell which heads had been stored in ice. Heads which had been in water on the bottom of the cartons were particularly prone to internal breakdown in the florets, soft rots, blackening of the scars left by removal of side leaves and strong odours. The MCT liner gave the best result overall (Figure 33). However, the differences between this packaging method and the plastic liner were often not significant. The main benefit in using MCT appeared to be reduction of stem scar discolouration. The additional costs incurred by using MCT therefore need to be considered in relation to the commercial benefits of this technology. Ice Plastic liner MCT Low permeability Lifespan High permeability Lifespan In AFAM+ Figure 33 - Heads of broccoli following storage in a modified atmosphere in ice, plastic liner or MCT liner, or storage in air + low or high permeability Lifespan bags. Using the readouts from individual thermocouples, total degree days during storage was calculated for each of the sample cartons (temperature x time). Using a standard linear regression analysis, there was little correlation between quality attributes and total degree days at outturn evaluation for any of the containers. However, there were weak (but statistically significant) correlations between colour (hue angle and yellowing) and degree days for both of the air containers when the product was stored for 2 days shelf life (Figure 34). This suggests that although this product appeared superficially similar to that from the modified atmosphere containers, those which had experienced higher storage temperatures were physiologically older. This meant they were more prone to breakdown on removal to normal retail temperatures. This effect may have been more strongly evident had the shipping time had been longer. 39

44 60 Degree days during storage Colour (Hue o ) Figure 34 - Correlation between total degree days in storage (time x temperature) and colour (measured as Hue o ) for individual cartons of broccoli stored in the static trial - air container for 21 days followed by 2 days at 20 o C. 40

45 Cauliflower quality As with broccoli, there were significant differences between the containers used in the static trial as well as between the treatments. All of the cauliflower was still acceptable for sale at the end of the trial. The importers in Dubai expressed concern with the colour of the curds, considering them excessively yellow (Figure 35). This was most obvious where the cauliflowers were unevenly coloured. The cauliflowers used in the trial were creamy rather than white. However, objective colour values recorded using the chroma-meter indicated that the colour of the cauliflowers was similar to that at harvest. It is concluded that the curd yellowness was due to variety or agronomy, and did not occur during storage. Figure 35 - Anthony Staatz (Koala Farms) and Mr Basheer (Ghulam Trading) examine cauliflowers Cauliflower was not stored under MA in the live shipment as this atmosphere had been reported to cause damage to the product. Some was included in the static trial as we were not relying on selling this product to meet shipping costs. We were therefore surprised to find that cauliflower stored under MA in the static trial suffered significantly less black spotting, softening and rots compared to cauliflowers stored with air (Table 5). This difference became more noticeable during shelf life; after 2 days at 20 o C 37% of air-stored cauliflowers scored black spotting = 2 or more (unsaleable), while only 22% of MA stored cauliflower were this quality. Whether this effect was due to lower storage temperatures in the MA container or the atmosphere itself is unclear and requires more research. Curd spotting and blackening was similar in the plastic and tissue wrapped heads (Figure 36), but weight loss and, therefore, softening was much greater in the heads wrapped in tissue. There had been concern that using LDPE bags would increase rot development, but this was not found in this trial. The cauliflowers sent to Dubai generally suffered more weight loss and curd blackening than those in the static trial. This would appear to reflect the higher storage temperatures used during the 41

46 Dubai shipment. However, although there was a small, but statistically significant correlation between degree days in storage and quality, total degree days were generally a poor indicator of curd blackening. Table 5 - Quality scores and weight loss for cauliflowers in the live and static trials. Values are means from evaluation following storage + 2 days at approx. 20 o C. Subjective assessments were done using standard scales shown in Attachment 1. Letters indicate values which are significantly different (p<0.05). Treatment Weight loss Blackening Softening Rots DUBAI SHIPMENT Air Plastic wrap 2.2 b 2.0 a 0.8 b 0.1 a STATIC TRIAL Tissue wrap 4.2 a 1.6 a 1.4 a 0.1 a MA Plastic wrap 1.2 b 1.0 c 0.4 c 0.3 b Air Plastic wrap 1.3 b 1.2 b 0.8 b 0.7 a Tissue wrap 4.1 a 1.4 a 1.1 a 0.6 a Tissue wrap Figure 36 - Cauliflower shipped to Dubai in air. Note uneven yellowing of curd. Colour values recorded with the chroma meter did not vary between the treatments or containers. This method of monitoring cauliflower quality appeared to have limited usefulness, as measurements of a small section of the head did not necessarily reflect the overall appearance. The quality of the cauliflower was much higher than some of that observed in the Central Markets, we observed cauliflowers which were severely softened and spotted due to the extreme heat (Figure 37). However, Australian produce is relatively expensive and therefore expected to be excellent quality. It is not anticipated that Australian exporters would seek to compete in this market. Plastic wrap Figure 37 - Cauliflowers on sale in the Dubai market 42

47 Lettuce quality The lettuces were in variable condition on arrival in Dubai. A significant amount of the lettuce was affected by soft rots, possibly Sclerotinia (Figure 38, 39a). This was probably related to the heavy rain which had occurred only a week before the shipment. A number were also affected by pink rib (Fig 39b). This was particularly evident where the mid ribs had been physically damaged. Figure 38 - Anthony Staatz and Hamid Ghaedi (Managing Director, Ghulam Trading) examine lettuce quality a. b. Figure 39 - Soft rots (a) and pink rib (b) on lettuces Quality grades given reflected the amount of stripping of the outer leaves necessary to obtain a good quality head. There were no significant differences between the packaging treatments (Table 6). Although the incidence of pink rib appeared to be slightly reduced in the MCT liners compared to the LDPE film (Figure 40) this was not statistically significant. Pink rib and browning of the vascular system were most common in large, solid lettuces; smaller looser heads were less likely to exhibit these disorders. Pink rib only rarely occurred where there was no physical damage and increased significantly during shelf life. 43

48 Table 6 - Quality grades of lettuce following shipping to Dubai in air and 2 days of shelf life Treatment Quality Butt colour Rots Internal quality Pink rib Air Plastic wrap 2.2 a 2.0 a 0.9 a 0.1 a 1.6 a MCT liner 2.2 a 2.0 a 1.2 a 0.2 a 1.3 a a. b. Figure 40 - Lettuce packed in individual plastic bags (a) or MCT liner (b) and shipped to Dubai in air On the second evaluation a significant number (58%) of heads were found to have russetting. No significant russetting was noticed at the original outturn. This disorder is associated with ethylene so may be related to the presence of apples and other fruit in the cool store. Lettuce not used for quality evaluation were stripped and repacked (Figure 41). Although the importers were disappointed with the amount of disease and disorders that were present, the shipment was still saleable. It is not believed that this repacking represented a prohibitive cost to the importer as labour is relatively inexpensive in Dubai and head lettuce was in strong demand in the market. Figure 41 - Stripping and repacking lettuce in Dubai 44

49 Financial analysis Summary of costs - Shipment to Dubai $ Fees payable to UAE Embassy, Canberra Australian Industry Group levy (2 x $30) 60 Certificate of Origin (2 x $60) 120 Fees for commercial invoice value UAE$30,001-60,000 (2 x $240) 480 Australia Post overseas documents courier (2 x $36) 72 Products Broccoli for AFAM+ container 9,088 Broccoli, cauliflower and lettuce for air container 8,439 AQIS Export permits and phytosanitary certificates 689 Transport of shipping containers to / from Gatton 690 Shipping costs to Dubai; Freight to Dubai (PIL / PAE) mid-july (2 x $3,379) 6,758 AFAM+ surcharge 338 Bunker surcharge (2 x $95) 190 Brisbane Port charges (2 x $69) 138 Equipment handling charge (lift on/off) (2 x $33) 66 Terminal handling charge (2 x $322) 644 Securities levy (2 x $15) 30 Documentation fee (2 x $50) 100 PRA and slot costs for Patricks (2 x $20) 40 Export Clearance Number fees (2 x $35) 70 TOTAL 28,012 Summary of income received - Shipment to Dubai $ Product in AFAM+ container, Shokri Hassan Trading Co., 14,768 Product in standard container, Ghulam Ali Abdullah Trading 13,956 TOTAL 28,724 Nett $712 Even though this was a trial rather than a true commercial shipment, we still managed to make a nominal profit. Under true commercial conditions a number of measures could be taken to improve profitability; Invoice fees paid to the UAE Embassy may not always be applicable Purchase of the broccoli, cauliflower and lettuce was relatively expensive. However, this includes transporting broccoli from Werribee in Victoria, which added a significant cost. 45

50 The AQIS inspection was of three different products, which increased the cost of this factor, especially as part of the inspection was conducted on a Saturday afternoon at penalty rates. Income received for the products in Dubai was decreased by the necessity of repacking the lettuce and curd yellowing of the cauliflowers. Returns may also have been affected by removal of some products for shelf life evaluation, the presence of different types of packaging, and even the fact that the importers were aware that this was a trial rather than a fully commercial activity. Summary of costs - Static trial $ PAE pre-trip inspection (2 x $65) 130 Hire of shipping containers ( Transport of shipping containers to Gatton 400 Transport of shipping containers to North Ryde 2,200 Products Broccoli + cauliflower for static trial 16,156 Hire of Food Science Australia container test facility 17,000 TOTAL 36,756 Summary of income received - Static trial $ Sunfresh and Fresh Fellas, Sydney Markets 3,031 TOTAL 3,031 Nett -$16,725 As with the shipment to Dubai, purchase of the broccoli and cauliflower was relatively expensive. Returns from the Sydney market were very low. The broccoli was in cardboard instead of Styrofoam, clearly marked as being for export, and little ice was present. These factors reduced saleability in a market already oversupplied with fresh product. Cauliflower was also in export cartons and individually bagged or tissue wrapped. These factors clearly marked this product as having been destined for the export market. Realistically, we were fortunate to gain even a modest return for these products, and were able to do so only because they were supplied to Food Service rather than general retail. Conclusions It was not the aim of this project to make a profit from conducting a shipment of vegetables to Dubai. However, it is encouraging that this activity paid for itself, at least in terms of the bottom line costs. It is interesting to note that almost $29,000 was received for the two containers in Dubai, while only $3,000 was returned for similar product on the Sydney Market. 46

51 Gross return on product in the AFAM+ container was slightly higher than that in the standard air container - $5,680 compared to $5,517. Part of this may be due to the cost of repacking lettuce from the air container. While the additional cost of using an AFAM+ was minor given the total cost of conducting the shipment, there do not appear to have been any significant benefits in terms of increased sale price due to better quality on arrival. Based on these results, use of an AFAM+ container to export broccoli to the Dubai market cannot be justified. However, this does not imply that this technology would not be useful for other crops or destinations. Even with travel expenses deducted, it was clearly more expensive conducting the static trial than the actual shipment. This was due to the cost of running the FSA facility, hiring and transporting the containers and the low returns gained in the Sydney Market. The results suggest that, so long as costs are carefully controlled, it is economically feasible to use sea freight to export vegetables into the Dubai market. Exporting in a 12m rather than 6m container could reduce freight costs and increase profitability. Many of the charges noted above are similar or only slightly more if exporting the larger container. For example, freight costs between Sydney and Dubai increase by less than half for the larger container (Table 7). Because of space savings relating to the door and cooling system a 12m high cube reefer holds more than twice as much as a 6m container; Volume 6m high cube reefer 30m 3 Volume 12m high cube reefer 64m 3 This means that the basic shipping costs might be $139/m 3 in a 6m container compared to $92/m 3 in a 12m container. Table 7 - Freight charges quoted by Maersk shipping, July 2005 Freight charges 6m reefer ($) 12m reefer ($) Ocean freight 3,654 5,256 Bunker charges and fees Port of origin charges Port of origin handling charge Port of origin documentation fee Security charges TOTAL $4,168 $5,869 The major disadvantage of using a large container is the volume of product required, both in terms of harvesting, packing and supplying in good time and sale in the destination market. These issues may be partly overcome using mixed loads of different products with similar storage environment requirements. Another potential issue is that 12m containers may develop larger temperature gradients than 6m containers. Previous studies by Food Science Australia have found that temperature gradients inside 12m containers can significantly affect outturn quality of fresh produce, particularly for sensitive fruit. However, the results of the current study indicate that vegetables are less sensitive to such gradients, so this may not be a significant problem. 47

52 Discussion and key points Loading the container Choice of container and container technology is limited by the shipping company used. For example, it is not possible to ship an AFAM+ container on a OOCL vessel, or to fit a MaxTend system to a Pacific International Line (PIL) or Maersk container. Products were tightly hand stacked inside the containers instead of palletised. Pallets used in shipping containers must be plastic or treated wood to meet quarantine requirements and are a different size to standard Chep pallets. Although hand stacking creates more work at loading, this helps ensure the floor is completely covered. This is important for even air flow from the bottom-up air delivery system. Temperature The MA container used in the static trial ran approximately 0.6 o C cooler than the static air container. As both containers had the same setpoint and load, it is likely this was due to calibration of the control probe. The MA container air delivery temperature of -0.9 o C could have damaged a load more susceptible to freezing injury. The static air container suffered significant evaporator frosting due to the combination of a setpoint <0 o C, fresh air exchange (10m 3 /h) and short defrost interval (6h). This increased temperature variability within the stow. Temperature variability within the stow was smallest in the standard reefer container shipped to Dubai. It s setpoint was >0 o C so evaporator frosting was minimal. In general, temperature control was good in all four of the containers monitored. There were no substantial off-power episodes and temperature variation within each container was not excessive Gas concentrations There was a substantial discrepancy (~4%) between the CO 2 concentrations recorded by the AFAM+ controller and the SenseAir CO 2 sensor. Recorded O 2 data suggests the latter was more accurate. Partly as a result of this, CO 2 remained lower than the 10% setpoint. Incorrect calibration of the CO 2 sensor could potentially result in damage to the container contents and/or loss of the benefits of using an AFAM+ container. The static MA container failed to reach 10% CO 2 due to leakage with the ambient air, estimated at approximately 0.6m 3 /h. Mean CO 2 concentrations inside the low permeability and high permeability Lifespan bags used in the Dubai shipment were found to be 4.2% and 3.3% respectively. Although lower than target concentrations, these CO 2 concentrations may still be physiologically active. Broccoli quality All of the broccoli was in marketable condition on removal from the containers. The Dubai importers were satisfied with product quality and have since enquired about further shipments. 48

53 Packing in ice consistently resulted in more stem and floret rots, increased scar discolouration and more odour than other treatments. Broccoli exported to Dubai is normally packed in ice, partly to alleviate effects of the extremely hot weather. Both of the Dubai importers were willing to accept broccoli not packed in ice, although one expressed a strong preference for Styrofoam containers over cardboard. The MCT liner gave the best result overall, but this difference was often not significant compared to a plastic liner. The results of this study suggest that the cost and ease of using the MCT liner would have to be comparable with plastic alone for this technology to be costeffective for broccoli shipped to Dubai. There was little or no evidence that shipping under MA or generating MA using a Lifespan bag had benefits compared to air alone. More differences might have been found had the shipping time been longer or temperatures higher. Based on these results, modified atmospheres are not necessary to ship broccoli to Dubai so long as temperature is accurately controlled. There was a weak but statistically significant relationship between broccoli colour and storage temperature calculated on a carton by carton basis. This relationship could be further defined using a wider range of storage time / temperature combinations. Such a model could be used to predict broccoli quality given a defined set of storage conditions. Cauliflower quality Curd yellowing was found to have resulted from pre-harvest rather than postharvest factors. Only a limited quantity of cauliflower was stored under MA in the static trial as 10% CO 2 had previously been reported to cause off odours and flavours. These effects were not found in this trial. Cauliflowers stored in MA suffered less curd blackening and softening than those in air, but it is not known how much of this effect was due to atmosphere, and how much to the lower temperature in the MA container. Curd blackening was similar in tissue and LDPE plastic wrapped heads, but weight loss and softening were reduced in the latter. Lettuce quality Outturn quality of lettuces was highly variable. The main issues were development of soft rots and pink rib. Soft rots were probably increased by the heavy rain which had occurred only a week before harvesting. Pink rib was strongly related to physical damage; the disorder was common where the fleshy mid-ribs had been crushed or split. Pink rib increased and extra rots developed during shelf life, despite removal of the outer leaves. Also, more than half of the lettuces developed russetting, suggesting that the cool room used for shelf life was contaminated with ethylene. The lettuces were repacked to remove damaged outer leaves and rots. This was worthwhile, as there was a strong demand in the market for crisphead lettuce and labour is relatively cheap in Dubai. Financial analysis Returns on the AFAM+ were similar to those from the regular air container, suggesting that use of this technology did not significantly increase the price paid by the importers. While use 49

54 of the AFAM+ technology represented a minor cost overall it appeared to have little benefit in this case. A small profit of ~$700 was made on the trial shipment to Dubai. A truly commercial shipment would be likely to have involved lower costs and been more profitable overall. This result suggests that sea freight of vegetables to Dubai is economically feasible. Sale of the products in the static trial on the Sydney market returned only $3,031, compared to $28,724 for the products in Dubai. Returns in Sydney were decreased because the products were packed for export and been stored for more than three weeks at a time when the market was oversupplied with broccoli and cauliflower. In contrast, there was strong demand in the Dubai markets for these products. Profitability of sea freight could be increased by using 12m instead of 6m shipping containers. This would reduce freight costs/m 3 by approximately 1/3. 50

55 Technology Transfer Technology transfer from this project has so far been limited as the steering committee felt that, given the potentially sensitive nature of some of the findings, communication of results should occur only once the final report was complete and provided to the committee for comment. The project steering committee will then decide the best way to communicate the results to the rest of the industry. At this stage it is tentatively planned to put out a media release and distribute an information pack to key vegetable exporters during March This will coincide with the AusVeg R&D meeting. The pack will contain a summary of the results, a CD with pictures and video from the project and other relevant information. Results will be presented at the AusVeg conference in May 2006 and submitted to a refereed journal for publication in the scientific literature. 51

56 Recommendations The results from this project are extremely encouraging with regard to further exports of vegetables from Australia to destinations such as the Middle East. The outlook may have become even more favourable in recent months. Maersk recently purchased P&O, expanding their fleet of container ships. The company is keen to develop reefer trade from Australia. Increased competition may help decrease freight rates, while faster, more frequent ships could reduce shipping times between Brisbane and Dubai to <20 days. Such opportunities should be investigated by the vegetable industry. This project has also identified some key areas requiring further work. Some of these are described in the proposal to extend this project, submitted to Horticulture Australia in November 2005; Examine the causes and control of curd blackening in cauliflowers Examine the causes and control of postharvest development of pink rib in lettuce Continue work on new packaging materials, such as MCT, for other vegetable crops. Determine how long other vegetable products can be stored under conditions achievable during sea freight and still retain good outturn quality and acceptable shelf life. Examine the effect of storage atmosphere on vegetable storability, particularly over time and at low temperatures. Atmospheres should include those possible using simple MA systems such as the AFAM+, the CSIRO MA pallet cover and the Sydney Postharvest Laboratory bin liner. The latter two technologies would allow products with different modified atmosphere requirements to be shipped in a single container. Test the effect of ethylene antagonists such as SmartFresh. Although ethylene antagonists have less effect at the low temperatures usually used during shipping, they may significantly increase shelf life on removal from long term storage. Define the influence of pre-harvest, postharvest and handling practices on storability. The current project used cauliflowers harvested with a new, minimal impact harvest aid which avoided product damage. In contrast, lettuces which had been exposed to difficult growing conditions subsequently developed pink rib and bacterial rots. Quantifying the effects of such factors on storage life would help growers and exporters when planning export shipments. Conduct a trial using a 12m shipping container, possibly comparing air with CA storage. Maersk Sealand have indicated that they would like to be involved in this activity and may be able to provide a container for a static trial or live shipment at significantly reduced cost. 52

57 References Amariutei, A., Tataru, D.P. and Tasca, G., Research results on refrigeration and CA storage of cauliflowers, Brassica oleracea L., var. Botrytis. Acta Hort. 62: Ballantyne, A., Stark, R., and Selman, J.D., Modified atmosphere packaging of broccoli florets. Int. J. Food Sci. tech. 23: Bastrash, S., Makhlouf, J., Castaigne, F. and Willemot, C., Optimal controlled atmosphere conditions for storage of broccoli florets. J. Food Sci. 58: Haginuma, S., Kubo, N., and Yamamoto, H., Studies on the optimum atmospheric conditions for controlled atmosphere storage of head lettuce. Report of the National Food Research Institute, Hokoku. 47: Ke, D. and Saltveit, M.E., Carbon dioxide induced brown stain development as related to phenolic metabolism in iceberg lettuce. J. Amer. Soc. Hort. Sci. 114: Kleiber, A., Jewell, L. and Simbeya, N., Ice or an ice-replacement agent does not improve refrigerated broccoli storage at 1 o C. HortTech. 3: Klieber, A. and Wills, R.B.H., Optimisation of storage conditions for Shogun broccoli. Scientia Hort. 47: Lipton, W.J. and Harris, C.M., Response of stored cauliflower (Brassica oleracea L., Botrytis group) to low O 2 atmospheres. J. Amer. Soc. Hort. Sci., 101: 3, Makhlouf, J., Castaigne, F., Arul, J., Willemot, C., and Gosselin, A., Long-term storage of broccoli under controlled atmosphere. HortSci. 24: Martinez, J.A. and Artes, F., Effect of packaging treatments and vacuum cooling on quality of winter harvested lettuce. Food Res. Int. 32: Menniti, A.M., and Casalini, L., Prevention of post-harvest diseases on cauliflower. Culture Protette. 29: 8, Mertens H., and Tranggono, Ethylene and respiratory metabolism of cauliflower (Brassica oleracea L. convar. Botrytis) in controlled atmosphere storage. Acta Hort. 258: Pogson, B.J. and Morris, S.C., Consequences of cool storage of broccoli on physiological and biochemical changes and subsequent senescence at 20 o C. J. Amer. Soc. Hort. Sci. 122: Postharvest Technology of Horticultural Crops, 3 rd edition 2002, ed. A.A. Kader, University of California Division of Agriculture and Natural Resources, Oakland, California. Shewfelt, R.L., Batal, K.M. and Heaton, E.K., Borccoli storage: effect of N 6 -benzyladenine, packaging, and icing on color of fresh broccoli. J. Food Sci. 48: Smyth, A.B., Song, J. and Cameron, A.C., Modified atmosphere packaged cut lettuce: effect of temperature and O 2 partial pressure on respiration and quality. J. Agric. Food Chem. 46: Snowden, A.L., A colour atlas of postharvest diseases and disorders of fruits and vegetables. Volume 2: Vegetables. Wolfe Scientific Ltd., London. 53

58 Stewart, J. and Uota, M., Carbon dioxide injury and market quality of lettuce held in controlled atmospheres. J. Amer. Soc. Hort. Sci. 96: Tomkins, R.B. and Sutherland, J., Controlled atmosphere for sea freight of cauliflower. Acta Hort. 247: Wilkinson, I. and Tomkins, B., 199_. The potential use of modified atmosphere packaging for fresh cauliflower export. Literature Review for ANL Ltd. Institute for Horticultural Development, Knoxfield, Vic. Wilkinson, I., Tomkins, B., Strickland, L. and Winkler, S., ANL seafreight project research program for iceberg-type lettuce. Report for ANL Ltd. Institute for Horticultural Development, Knoxfield, Vic. 54

59 Attachments Attachment 1 - Grading scales 55

60 Floret rots 0 - no rots in florets 1 - very slight, a few dark florets 2 - slight, <5% florets with rots 3 - moderate, 5-10% florets rotten, slight lesions 4 - severe, greater than 10% florets rotten, obvious slimy lesions Softening 0 - entire head crisp, firm 1 - florets firm, movement between branchlets 2 - florets softening, up to 15mm movement in branchlets 3 - florets soft, wilted, branchlets rubbery and flexible 4 - entire head wilted, unacceptable Odour 0 - nil off odour, fresh broccoli smell 1 - very slight odour, inoffensive 2 - slight off odour, noticeable when held up to nose 3 - moderate off odour, offensive when 10cm from nose 4 - extremely stinky, revolting even at arms length 56

61 57

62 Cauliflower softening 0 - florets tight, hard 1 - slight movement in florets, firm 2 - up to 5mm movement in outer floret layers, softening 3 - up to 10mm movement in outer florets, rubbery 4 - >10mm movement, soft, floppy Cauliflower rots 0 - no rots in stem or base 1 - slight rots <20mm diameter 2 - significant rots >20mm or soft, mushy 58

63 59

64 Attachment 2 - Air delivery and return temperatures Variation in mean air delivery and return temperatures between the left wall and right wall of shipping containers AFAM+ shipped to Dubai. Mean air temperature ( o C) Return Delivery Distance from left wall (m) Standard air container shipped to Dubai 4 Mean air temperature ( o C) Distance from left wall (m) 60

65 MA container used in static trial at North Ryde Mean air temperature ( o C) Return Delivery Distance from left wall (m) Air container used in static trial at North Ryde 1 Mean air temperature ( o C) Return Delivery Distance from left wall (m) 61

66 Attachment 3 - Cargo temperatures Histograms showing the frequency of cargo measurements over the duration of the voyage to Dubai (a) and the static trial at North Ryde (b) 140 (a) Frequency ('000 readings) AFAM+ Air Temperature ( o C) (b) Frequency ('000 readings) Modified Atmosphere Air Temperature ( o C) 62

67 Attachment 4 - Contour plots showing spatial temperature profiles Temperatures during shipping to Dubai 63