Maximizing Post Maximizing Post--Harvest Quality Harvest Quality Hydrocooling cold water. cools without moisture loss

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1 3) Hydrocooling - commodity immersed, flooded or showered with cold water. - more rapid cooling than forced air ** - cools without moisture loss - cleans product, floats off debris etc. - water may spread decay microbes - Limited to commodities which tolerate exposure to free water Maximizing Post- Harvest Quality Step 2. Longterm storage Goals -slow ripening, i senescence of commodity - slow activity of decay organisms. - minimize moisture loss. - maintain quality. Requirements for Longterm Storage Structures - Generate and maintain steady, low temperatures - Hold/support the commodity - Allow efficient movement of commodity - Ventilation system - Humidity delivery and control Maximizing Post- Harvest Quality Maximizing Post- Harvest Quality Step 2. Longterm storage Longterm storage General Recommendations Temperature.. as low as can go without damaging commodity or the building (condensation) Humidity.. as high as possible without condensation Airflow.. as little as possible without starving crop. General Recommendations Potato.. 4C + 95% RH Strawberry 0C + 95% RH Carrot -1C + 100% RH Garlic -1C + 50% RH 1

2 Step 4. Cleaning Removal of soil, dust, pesticide residues, excess sap and other foreign matter (ie; microbes, bug parts etc). Cleaning - Improves appearance of the product Increase lifespan by removing decay causing microbes Improves food safety? Step 4. Cleaning Cleaning gp process - basic wipe to substantial brushing, water blast etc. - scrubbing - damages skin = increased decay - removes waxes = moisture loss and decreased consumer appeal. Step 4. Cleaning Cleaning gp process - some products will not tolerate exposure to water ie; cabbage splits, onions rot - watch for spread of bacteria in wash water. - change water frequently - use disinfectants ( ppm chlorine). CDC confirms 13 dead in listeria cantaloupe outbreak Infections hit elderly victims and children hard; more illnesses, deaths may be confirmed When to wash; before or after storage? Recommend cleaning before unless contra-indicated ie; Root crops - stored dirty as soil acts as a barrier to moisture loss during storage = beneficial. After washing, free water cannot persist on the commodity = decay Air drying is usually sufficient, especially if heated air is used. Step 5. Trimming 1) usually decreases water loss - gets rid of useless, damaged d tissues 2) slows development of disease and decay 3) reduces the weight of the commodity = less shipping, storage and handling costs. Avoid excess trimming,, particularly of marketable portion = as weight lost = profit lost if selling by weight. 2

3 Step 6. Disinfestation Treatments which control post-harvest diseases Starts (ends?) with disease control in field Final step = treatment in storage Post-harvest t treatments t t must be extremely safe as product is consumed soon after treatment. Attacks in the field.. but does damage post-harvest Overwinters as spores on dead leaves from last year s crop Water /wind moves spores onto flower petals.. and into developing fruit Development accelerates as fruit mature Development and spread requires. Temps 20C is optimal.. but still working at 0C High RH Look for signs of damage beginning at flowering Scout deep in canopy = high RH Management Avoid susceptible cultivars Kent Till under crop residues at renovation Avoid longterm high h RH Adequate plant/row spacing Careful N application Timing of irrigation to allow canopy to dry Drip irrigation is best Management Application of fungicides.. beginning at flowering time Captan, Bravo, Cabrio, Lance, Nova, Rovral, Scala Read label Watch for pre-harvest intervals and rotation 3

4 Special Treatments Controlled atmosphere storage Supplements effects of good post-harvest management Reduce O2 and increase CO2 around fruit Slows respiration and development of disease Can double post-harvest lifespan 4

5 Special Treatments Controlling Potato Sprouting Cultivar selection Low temperature storage Sprout inhibiting i chemicals Mechanical desprouting Special Treatments Step 7. Sorting/grading Carrot dehydration Cultivar selection Low temperature high RH storage Filacell ll storage Re-hydration Sorting - selecting for items with the desired maturity, color, shape etc Sorting - to meet grade or quality standards set by the consumer, industry or the government. Sorting of horticultural crops is primarily done by hand. Expense/speed/difficulty of sorting are a function of; 1) # of decisions, separations or grades involved, 2) size of commodity, 3) speed required 4) accuracy required. Step 7. Sorting/grading Sorting ; Sorting/grading system 1) high capacity, 2) accurate 3) minimal injury to the commodity, 4) flexible = applicable for more than one commodity, cv. or set of grading/sorting standards. In field - Leaves culls behind, but slows harvest In sorting house - reduces exposure of crop and workers to field conditions - allows efficient use of sorter's time and machinery. Pre-storage - remove culls that take up space in storage and potentially spread disease. Pre-market - achieve required quality just prior to marketing 5

6 Step 8. Packing Packing - assembly of a given quantity of commodity (count or weight) into container. Step 8. Packing Packing... 1) allows orderly handling, 2) protects the commodity. - immobilize commodity to reduce abrasion. - cushion the commodity - protect it against crushing Best time to pack depends on the commodity - very sensitive crops (strawberry) picked into pack. - otherwise pack later as washing, cooling and sorting are made difficult by packing.. Also weight of packaging materials increases transportation costs. When to package? Option #1. At point of origin -packaging adds protection during shipping. i - packaging done by pro s under ideal conditions Option #2. At point of sale by customer? - increased handling of commodity = damage and sanitation - increased check out times -non-uniformity of sizing/pricing Farmers markets are great..., One day they re going to kill some people though. Canadian Food Summit - Feb 7,

7 Maximizing Post-Harvest Quality AFFLFSC 2012 Doug Waterer 7