Bacteriological Survey of the Blue Crab Industry

Transcription

1 APPLIED MICROBIOIloGY, Dec. 1972, p CopyrightO 1973 American Society for Microbiology Vol. 24, No. 6 Printed in U.S.A. Bacteriological Survey of the Blue Crab Industry FRED A. PHILLIPS AND JAMES T. PEELER Division of Microbiology, Food and Drug Administration, Washington, D.C Received for publication 16 August 1972 During sanitation inspections of 46 crabmeat processing plants on the Atlantic and Gulf Coasts, 487 samples of whole crabs immediately after cooking, cooked crabs after cooling, backed or washed (or both) crab bodies and whole crab claws, as well as 1,506 retail units of finished product were collected and analyzed bacteriologically. The 1,506 retail units (1-lb [ g ] cans) included 518 cans of regular (special) meat, 487 cans of claw meat, and 501 cans of lump meat. Statistical analyses showed that crabmeat from plants in Mississippi, Louisiana, and Texas had higher counts in 19 of 24 cases for the four bacteriological indices than crabmeat from plants located along the Atlantic Coast and the Gulf Coast of Florida. Aerobic plate counts of retail units collected from a previous day's production were significantly higher than those collected on the day of inspection. Regular crabmeat had consistently higher aerobic plate counts than claw or lump meat. When the product was handled expeditiously under good sanitary conditions, the bacteriological results were significantly better than the results from plants operating under poor sanitary conditions. Crabmeat produced in plants operating under good sanitary conditions had the following bacteriological content: (i) coliform organisms average most-probable-number values (geometric) of less than 20 per g; (ii) no Escherichia coli; (iii) coagulasepositive staphylococci average most-probable-number values (geometric) of less than 30 per g in 93% of the plants; (iv) aerobic plate count average values (geometric) of less than 100,000 per g in 93% of the plants, with the counts from 85% of these plants below 50,000 per g. An outbreak of food poisoning in Chicago in September, 1926, from crabmeat containing Salmonella suipestifer led to an investigation by the Food and Drug Administration (FDA) of the crabmeat industry in Maryland and Virginia (5). It was determined that crabmeat was being produced under grossly insanitary conditions, which were reflected by the high incidence of coliform organisms in the finished product. In 1932, additional outbreaks of food poisoning in Washington, D.C., Baltimore, Md., and Philadelphia, Pa., were traced to microbial contamination in crabmeat (5). During the past 4 decades, the FDA has been taking regulatory action against firms producing crabmeat under insanitary conditions when the observed insanitary conditions were substantiated by the presence of indicator organisms such as E. coli and coagulase-positive staphylococci, and by high coliform organisms and aerobic plate counts (APC). During the last decade, the FDA has been conducting bacteriological surveys to determine the numbers and types of certain microorganisms in food prod- 958 ucts and relating their presence to sanitary conditions observed in the plants (6-9). This paper reports the results of such a survey of the blue crab processing industry along the Atlantic and Gulf Coasts in 1968 and The primary purpose of this survey was to determine the relationship of industrial sanitary practices to the microbiological quality of freshly picked blue crabmeat that was neither frozen nor pasteurized. The blue crab (Callinectes sapidus Rathbun) is fished commercially from Maryland to south of Galveston, Texas. The greatest concentration of the industry is in the Chesapeake Bay area. Crabs are brought to the processing plant alive and are generally cooked immediately either in boiling water or in a steam retort. The latter method is most common, with cooking times ranging from 7 to 23 min at approximately 121 C (approximately 15 psi). Cooked crabs are usually cooled at ambient temperatures for 3 to 16 hr. Where the firms are equipped with refrigeration facilities, the crabs are placed in a cooler for storage until the beginning of opera-

2 VOL 24, 1972 BACTERIOLOGICAL SURVEY OF BLUE CRAB INDUSTRY tions. Cooler temperatures are usually between 4.4 and 6.7 C, although some were as high as 15.6 C at the time of inspection. Two different processes are used to prepare the crabs for removing the meat (picking): a wet process and a dry process. Forty-four percent of the firms inspected used the wet process in which the crabs are backed (carapace removed) and declawed. The crab bodies are then washed by hand or machine and the meat is removed immediately, or the bodies may be refrigerated overnight. The claws are picked separately. The dry process, most commonly used in the Chesapeake Bay area, does not include the washing step. Each employee backs, declaws, and removes all the meat from each crab. Sometimes the claws are picked separately as in the wet process. There are three general types of crabmeat: (i) regular or special, consisting of white body meat; (ii) lump or backfin, consisting of the large pieces of body meat taken from the muscles which control the back swimming legs; and (iii) claw, consisting of the darker meat taken from the claws. The crabmeat is packed into 1-lb metal or plastic cans with snap-on lids or packed into 5- to 6-lb ( to g) plastic bags. The finished product is placed in wet ice, stored in the cooler, and shipped in wet ice, usually within 3 days. The crabmeat in the plastic bags is sold for further processing into crabcakes, deviled crabs, etc.; crabmeat in the 1-lb cans is intended for the retail market. MATERIALS AND METHODS Collection of samples. A total of 53 inspections of 46 processing plants were made by inspector-microbiologist teams during May to October in 1968 and The inspected plants were located in three geographical areas: Baltimore (Maryland, Virginia, and North Carolina); Atlanta (South Carolina, Georgia, and Florida); New Orleans- (Mississippi, Louisiana, and Texas). The majority of the inspected plants were located on the Gulf and southern Atlantic Coasts. During each inspection, samples were collected aseptically at various stages of processing. These samples were limited to whole crabs immediately after cooking, whole cooked crabs after cooling overnight, backed or washed (or both) crab bodies, and whole crab claws. Retail units (1-lb cans) of each type of crabmeat were collected from that produced on the day of inspection. When available, retail units of at least one type of crabmeat produced on a date prior to the inspection were collected. Immediately after collection, the samples were placed in wet ice in the firm's cooler. After the inspection was completed, samples were packed in an ice chest with wet ice and transported to the laboratory. The analyses, in which four FDA district laboratories participated, were 959 started within 48 hr after collection. A total of 1,506 retail units were collected including 518 cans of regular meat, 487 cans of claw meat and 501 cans of lump meat. Also, 487 samples were collected of whole crabs immediately after cooking, cooked crabs after cooling, backed or washed (or both) crab bodies, and whole crab claws. Analytical procedures. Aerobic plate counts, coliform, E. coli, and coagulase-positive staphylococcus counts were determined on samples by the official first action method for the examination of frozen, chilled, precooked, or prepared foods ( ) of the Association of Official Analytical Chemists (1). Correlation of bacterial findings with inspectional evidence. Establishment inspection reports prepared by the inspectors were evaluated, and the firms were classified as good or poor based on the degree of the insanitary conditions observed. Plants which received good ratings were not necessarily operating under ideal sanitary conditions, but their operations were visibly cleaner than those of poor plants. The bacteriological results were statistically analyzed to determine if significant differences occurred (i) between plants rated good versus those rated poor; (ii) among the three types of crabmeat examined; (iii) among the three geographical areas; and (iv) between production lots. Statistical procedures. Tests of significance were performed by using logarithms of counts per gram and percentage of positive units. The logarithms of the counts were assumed to be normally distributed, and tests of significance and confidence limits were computed by using normal theory (Ostle [3D. The differences between good and poor plants and between geographical areas were examined by using the within-lot variation as the estimate of random error. Since a large number of observations were reported as <3, frequency distributions and percentage of positive units were found to be more useful in evaluating the differences for coliform organisms, E. coli, and coagulase-positive staphylococci. RESULTS Plants operating under poor sanitary conditions displayed many poor employee practices, building and equipment defects, and operational inadequacies which contributed to contamination of the finished product. Flies and other insects entered through various windows and door openings. Equipment such as carts and dollies used to transport cooked crabs in wire baskets were rusted and pitted and were very seldom cleaned or sanitized. Cooked crabs came into contact with unsanitized objects such as retort hoist chain, cooler walls, employees' clothing, and rusted storage racks, and were usually air-cooled in areas subject to dust and flies. Cooked crabs frequently were not rotated on the picking tables, so that some crabs remained at room temperature for several hours. In addition, some picked crabmeat was left at room temperature for several hours before

3 960 PHILLIPS AND PEELER APPL. MICROBIOL. being iced. Other practices observed in poor plants included failure of employees to wash and sanitize their hands after touching unsanitized objects, reuse of paper towels and rags, and chlorine dip stations for hands and equipment with less than an effective amount of residual chlorine. Floor filth was introduced to cooked crabs by splatter from water during clean-up operations or by contact of baskets of crabs directly with the floor. Crab claws were left at room temperature most of the day and picked last. In contrast, the plants operating under good conditions of sanitation had fewer insanitary infractions by employees, handled the product quickly, and maintained buildings and equipment in reasonably good condition. However, some of the plants classified as good had very few employees present on the day of inspection, and other plants operated only part of a day. Thus, the opportunity for bacterial buildup was minimized. The cooking times and temperatures, with the exception of the processing plants that boiled crabs, were usually difficult to establish due to either the lack or the malfunctioning, or both, of temperature and pressure gauges. In most cases, the cooking times for the crabs were not sufficient to sterilize them. Sample results of whole crabs collected immediately after cooking showed that 83% of the 104 samples collected had APC values below 10,000/g. Three samples were over 100,0001g. TABLE 1. Table 1 shows a comparison of bacteriological results of samples collected at various stages of processing for plants observing good and poor sanitary practices. In the plant operating under good sanitary practices, crabs were cooked for 23 min at approximately 121 C, which was sufficient to reduce the population density to less than 300/g. The plant operating under poor sanitary conditions cooked the crabs for 10 min at the same temperature, and the geometric average APC of two samples was 1,800/g; one sample had an APC of 310,000/g. All samples of cooked crabs were free of coliform organisms, E. coli, and coagulase-positive staphylococci. The results for the poor plant show an increase in counts for all four bacteriological indices after backing, washing, and cooling overnight. The results for the good plant showed an increase in APC after overnight cooling and the appearance of low numbers of coliform organisms, but the samples contained no E. coli and only low numbers of coagulase-positive staphylococci after handling by the employees removing the meat. The low level of counts in the good plant was probably due to the expeditious handling of the crabs. The whole claws were grossly mishandled in the poor plant (Table 1). They were left at room temperature for several hours and allowed to touch unsanitized or rusty equipment, or both. Since claws are more difficult to pick than are the bodies, they remained on the picking tables at room temperature for longer periods of time. Comparison of bacteriological results at various stages of processing for plants observing good and poor sanitary practices Good plant Poor plant Coag- Coag- Coli- E. ulase- Coli E ulase- Description of samples" forms coli positive forms coli positive (MPN/ (MPN/ staphy- APC/g (MPN/ (MPN/ staphyg~ g g) ) lococci g lococci g) g (MPN/ (MPN/ APC/g g) g) Whole cooked crab after retorting <3 <3 <3 <300 <3 <3 <3 1,800 Backed cooked crabs after washing <3 < <3 340,000 Backed cooked crabs after cooling overnight (3.3 C).<3 <3 <3 100, ,000,000 Backed cooked crabs from picking table.1.9 <3 <3 5, ,000 Cooked crab bodies from picking employee.1.9 < , < ,000,000 Whole claws after cooling overnight (3.3 C) <3 <3 3,200 > 1, ,000,000 Whole claws from picking table <3 <3 7, <3 <3 750,000 a Results are geometric averages of two samples collected at each site. 5MPN, most-probable-number.

4 VOL 24, 1972 BACTERIOLOGICAL SURVEY OF BLUE CRAB INDUSTRY APC (geometric means) and 99% confidence limits for three geographical areas and three types of meat produced in good and poor plants are shown in Table 2. Significant differences between the New Orleans- area and the other two areas were observed for regular and lump meat in both good and poor plants by Duncan's (2) test. This difference was probably due to the higher mean temperature and humidity in the New Orleans- area, which afforded better incubation conditions. The claw meat did not show significant differences among the New Orleans-, Baltimore, and Atlanta areas for good plants, but did show significant differences between good and poor plants. This was probably due to the differences in operating procedures in the various areas. Some poor plants in the Baltimore area allowed the claws to remain in wooden baskets all day at room temperature and were picked last, whereas in the other areas the claws were picked simultaneously with the crab bodies. When the claws were handled expeditiously and kept cool, the counts remained at a low level all through the process. As further evidence of the differences between good and poor plants, the overall APC geometric mean per gram was: for regular meat, 18,000 for good plants and 190,000 for poor plants; for claw meat, 15,000 for good plants and 170,000 for poor plants; for lump meat, 7,900 for good plants and 75,000 for poor plants. The overall within-lot variance in log,0 units was about the same for all three types of meat. Values for regular, claw, and lump meat were , , and , with 465, 436, and 444 degrees of freedom. Tables 3 and 4 summarize the results of the TABLE 2. bacteriological examinations of regular meat retail units from plants operating under good and poor sanitary conditions, respectively. Most of the samples from good plants contained coliform organisms and coagulase-positive staphylococci, but the geometric averages were very low because most of the retail units were negative (Table 3). The APC geometric averages were below 50,000/g with the exception of plant no. 4. The higher APC average in this sample could not be explained, since the claw and lump meat collected the same day had much lower counts. None of the retail units from the good plants contained E. coli. Table 5 shows the percentage of good and poor plants with aerobic plate counts in seven count ranges for the three types of crabmeat. Regular meat from good plants had APC values (geometric means) below 100,000/g 93% of the time; all samples of claw and lump meat were below this level. This compares with 41, 34, and 51% for regular claw and lump meat (poor plants), respectively, which were below 100,000/g. The regular meat APC values (geometric means) from poor plants were above 1,100,000/g 23% of the time, with the claw and lump meat each above this level 5% of the time. Table 6 summarizes the results for coliform organisms, E. coli, and coagulase-positive staphylococci by the percentage and number of plants having geometric averages in four count ranges. All coliform counts (geometric means) for all three types of crabmeat from good plants were below 20/g (most-probable number [MPN D. Coliform counts (geometric means) for regular, claw, and lump meat were below 10/g (MPN) in 39, 42, and 49% of the poor plants, respectively, while the counts were above 50/g (MPN) in 36, 21, and 23% of the poor plants. All values (geometric means) for E. coli, good, and poor plants, were below 10/g (MPN). Coagulase-positive staphylococci values (geometric means ) for regular, claw, and lump meat were below 10/g in 79, 69, and 77% of the good plants, respectively. The counts were below Aerobic plate count per gram geometric means for three geographical areas and three types of crabmeat produced in good and poor plants Reagular T Claw Lump Source Mean 99% Confi- Mean 99% Confi- Mean 99% Confidence limits dence limits dence limits Good plants Baltimore... 16,000 (70)a 10,000-26,000 10,000 (57) 6,000-19,000 9,000 (57) 5,400-15,000 Atlanta... 18,000 (58) 11, ,000 (50) 14,000-32,000 5,800 (49) 4,000-8,400 New Orleans ,000 (10) 39,000-53,000 21,000 (10) 8,200-51,000 18,000 (10) 6,100-51,000 Poor plants Baltimore ,000 (85) 95, , ,000 (85) 140, ,000 53,000 (85) 37,000-77,000 Atlanta ,000 (160) 100, , ,000 (150) 140, ,000 66,000 (160) 49,000-90,000 New Orleans ,000 (135) 230, , ,000 (135) 99, , ,000 (140) 77, ,000 a Number of observations per mean. 961

5 962 TABLE 3. Plant PHILLIPS AND PEELER APPL. MICROBIOL. Results of analysis of regular crabmeat collected from plants operating under good sanitary conditions Area MPN of MPN of MPN of coagulase- No. o' coiform E. clilg positive APC/g units' organismslg. cometic/ staphylo- (geometric Range of APC/g (geometric (emetric cocci/g mean) memean) ean (geometric mean) 1 BLTc d (3)e <3 2.8 (4)e 25,000 2,700-18,000,000 2 BLT (2) < (4) 19,000 6,500-67,000 3 BLT (6) <3 <3 4,300 1,300-19,000 4 BLT 10 < 3 < 3 < 3 150,000 2, ,000 5 BLT 10 <3 <3 1.8 (3) 8,900 4,300-42,000 3 BLT (4) <3 6.6 (9) 11,000 5,000-26,000 6 BLT 10 <3 <3 7.4 (8) 9,500 3,400-39,000 7 ATL (7) <3 1.1 (1) 17,000 5, ,000 8 ATL (3) < (2) 18,000 5,500-68,000 9 ATL (5) < (8) 17,000 6, , ATL (3) < (8) 17,000 5, ,000 9 ATL (7) <3 3.4 (6) 17,000 3, ,000 8 ATL (3) <3 1.2 (1) 16,000 3, , NOL-DAL (7) < (9) 45,000 20, ,000 a A unit, 1-lb retail package. " MPN, most-probable-number. C BLT, Baltimore; ATL, Atlanta; NOL-DAL, New Orleans-. d Indicates that one or more unit(s) had an MPN of >1,100/g. In these cases, the value of 1,100/g was used to calculate the geometric mean. e Number in parentheses indicates number of units positive. 10/g (MPN) in 54, 55, and 62% of the poor plants, and above 50/g (MPN) in 21, 24, and 15% of the poor plants. Since coagulase-positive staphylococci are normally found on the human skin and crabmeat is picked by hand, it was expected that these organisms would be present in the finished product. In some cases, coagulase-positive staphylococci counts from finished product units within a lot varied greatly, even when collected from good plants. This could be due, in part, to the difference in the microflora of each employee's hands, since most retail units of finished product represented crabmeat picked by one employee. This difference was demonstrated by Puncochar and Pottinger (4). However, where the product was handled expeditiously and under good sanitary conditions, the finished product counts were usually low. Tables 7 and 8 show the percentage of retail units positive for coliform organisms, E. coli, and coagulase-positive staphylococci for good and poor plants, respectively, and compare products from the three geographical areas. In all three analytical categories and all types of crabmeat, except the coliform results of claw meat from the Atlanta area poor plants, the percentage of units positive was significantly higher in the New Orleans- area than in the Baltimore and Atlanta areas, regardless of whether the retail units were from good or poor plants. There was very little difference among the types of meat for all geographical areas and all analytical categories. Some differences were noted between good and poor plants in the percentage of units positive for coliform organisms. The percentage of units positive for E. coli in the Baltimore and Atlanta area poor plants was relatively low compared with the New Orleans- area, and, as stated before, the products of the good plants had no E. coli. Coagulase-positive staphylococci results did not vary significantly, although the poor plants had a slightly higher percentage of units positive for most of the types of meat in the Baltimore and Atlanta areas. The retail units from the New Orleans- area good plants, however, were higher than the units from the poor plants. This could be due to the fact that fewer units were examined from good plants, since coagulase-positive staphylococci results were shown to vary considerably between lots, regardless of whether the samples were from good or poor plants. Tests were performed on geometric means observed on retail units packed the day of the inspection and units packed on a date prior to the inspection. The APC results in Table 9

6 VOL. 24, 1972 BACTERIOLOGICAL SURVEY OF BLUE CRAB INDUSTRY 963 TABLE 4. Results of analysis of regular crabmeat collected from plants operating under poor sanitary conditions * ~. MPN of MPN of MPN of coagulase- No. of coliform E. coliljg positive APC/g Plant Area organisms/g (geome ticstaphylo- (geometric Range ofapc/g (geometric ) Cocci/g mean) mean)' mean (geometric mean) 12 BLTc (6)d < (9)d 36,000 12, , BLT 5 <3 < (5) 50,000 33,000-71, BLT (7) 2.4 (4)d <3 1,000,000 1,300-18,000, BLT (8) <3 1.3 (1) 35,000 5, , BLT Oe (10) 1.4 (2) 11.0 (8) 2,200, ,000-8,800, BLT (9) 2.5 (4) (9) 1,100, ,000-3,600, BLT (3) 1.2 (1) 2.4 (3) 7,100 5,000-11, BLT (6) < (10) 150,000 19,000-3,000, BLT (2) < (9) 96,000 2, , ATL Oe (10) 1.1 (1) 1.2 (1) 190,000 34,000-2,000, ATL (4) <3 6.9 (7) 22,000 6, , ATL (5) <3 4.5 (6) 94,000 6, , ATL (8) <3 4.1 (4) 69,000 9, , ATL (8) < (3) 1,200, ,000-6,900, ATL (10) (1) 16.0 (9) 120,000 33,000-1,200, ATL (2) < (9) 38,000 4, , ATL (4) < (8) 89,000 30, , ATL (6) (1) 2.1 (3) 360,000 14,000-11,000, ATL e (7) <3 7.0 (5) 33,000 11,000-75, ATL (3) <3 4.5 (5) 14,000 2, , ATL Oe (10) < (4) 140,000 7,000-2,400, ATL Oe (10) (1) 6.2 (8) 2,100, ,000-9,500, ATL Oe (7) <3 1.5 (2) 1,200, ,000-5,600, ATL (10) < (8) 380,000 36,000-2,700, ATL (10) 1.5 (3) 36.0 (9) 47,000 12, , NOL-DAL (9) 2.6 (5) 4.9 (7) 360, ,000-12,000, NOL-DAL Oe (10) 2.8 (4) 2.3 (4) 620,000 55,000-3,300, NOL-DAL (10) 2.5 (4) 24.0 (8) 17,000 8,800-40, NOL-DAL Oe (10) 3.5 (4) 43.0 (8) 120,000 12, , NOL-DAL (5) 3.8 (3) (5) 2,000, ,000-16,000, NOL-DAL (3) 1.1 (1) (10) 38,000 30,000-61, NOL-DAL (6) < (10) 74,000 9, , NOL-DAL (10) 1.1 (1) (10) 270, , , NOL-DAL (10) 1.6 (3) 1.3 (2) 420,000 94,000-4,000, NOL-DAL (10) 1.4 (2) 21.0 (10) 700,000 57,000-3,500, NOL-DAL (10) 1.4 (1) 1,070.0 (9) 1,500,000 65,000-16,000, NOL-DAL e (9) 6.4 (4) 74.3 (10) 3,800,000 50,000-97,000, NOL-DAL (9) 1.4 (2) 9.5 (8) 110,000 27,000-1,400, NOL-DAL e (10) 10.5 (7) 7.3 (9) 2,500, ,000-5,800,000 I I I I I aa unit, 1-lb retail package. MPN, most-probable-number. c BLT, Baltimore; ATL, Atlanta; NOL-DAL, New Orleans-. d Number in parentheses indicates number of units positive. eindicates that one or more units had an MPN of >1,100/g. In these cases, the MPN value of 1,100/g was used to calculate the geometric mean. indicate that the previous day's samples tend to have a higher mean count per gram. This difference was significant for all three types of meat. APC geometric means from a previous day's production were higher than those obtained on the day of inspection in 14 of 21 instances for the plants packing regular meat, 11 of 12 instances for plants packing claw meat, and 5 of 8 instances for plants packing lump meat. This difference has been observed previously with other food samples analyzed by FDA, and seems to indicate that most firms are

7 964 PHILLIPS AND PEELER APPL. MICROBIOL. TABLE 5. Percentage of plants with aerobic plate counts (geometric means) in severs count ranges Count ranges of APC/g Good plants Poor plants (geometric mean) Regular Claw Lump Regular Claw Lump 0-100, , , , , , , , , ,000-1,000, ,100,000-up TABLE 6. No. of plants Percentage and number of plants having geometric means in four count ranges for coliform organisms, E. coli, and coagulase-positive staphylococci Count Regular Claw Lump conditions range No of No. of No. of o (emti)plants plants plants Coliform organisms Good plants Poor plants up E. coli Good plants Poor plants Coagulase-positive Good plants staphylococci up Poor plants up on their best behavior during inspection and are aware of certain good manufacturing practices. Although the possibility exists that the higher mean counts of the previous day's production could have been due to the additional 24-hr incubation period, even though the product was stored in ice, the probability of significant bacterial growth during this period is not likely. DISCUSSION Tobin and McCleskey (10) showed that the steaming process destroyed all coliform organisms and greatly reduced the numbers of other bacteria in the whole crabs. The results from the few samples of cooked crabs analyzed in our survey confirmed their findings. Furthermore, our survey detected no coagulase-positive staphylococci after the crabs were cooked either by steam retort or boiling. Thus, the presence of large numbers of either coliform organisms or coagulase-positive staphylococci in the finished product indicates insanitary conditions during processing. As a result of a study of the sanitary requirements for crabmeat processing plants, Puncochar and Pottinger (4) reviewed the state of the industry and also made suggestions for technological improvements. The cooking times they reported ranged from 15 to 22 min at pressures of 12 to 18 psi, and were sufficient to kill all bacteria except for a few heat-resistant sporeformers. However, our survey indicated that the industry is generally cooking for 8 to 12 min at approximately 15 psi and, therefore, is not getting a sterile cook. Their study also showed a marked increase in total counts on cooked crabs cooled overnight. Industry practices have

8 VoL 24, 1972 BACTERIOLOGICAL SURVEY OF BLUE CRAB INDUSTRY changed in that most firms air-cool for only a few hours and then refrigerate, rather than air-cool all night. However, the coolers used now are not of a construction design to insure sanitary conditions, and the crabs contact rusty racks, cooler walls, and sometimes raw fish used as crab bait. Since the crabs are not generally sterile when placed in the coolers, which are usually above 4.4 C, there is the possibility of bacterial growth during the overnight cooldown cycle. This may explain why the samples of cooked, cooled crabs in our survey showed a marked increase in counts over the cooked crabs taken out of the retort. Punochar and Pottinger (4) also studied the microflora of the employee's hands and found that 44% were carriers of E. coli. Washing with soap and water followed by sanitizing in a chlorine solution greatly reduced the microflora of the hands, if done periodically throughout the day. Many of the plants inspected had inadequate toilet facilities. Some had no hand washing facilities in or near the toilets, which meant the employees had to enter the processing area to wash their hands. Doors, faucets, and other objects handled before washing could then become a source of contamination with E. coli and other bacteria. The employees also TABLE 7. Percentage of retail units positive for coliform organisms, E. coli, and coagulase-positive staphylococci in three geographical areas collected from plants operating under good sanitary conditions Aranen 99% Con- Organism Area Regular Claw Lump Aid nte Coliform organisms Baltimore 21.4a (70)b 10.5 (57) 14.0 (57) 25.2 (341) Atlanta 48.3 (58) 36.0 (50) 22.4 (49). New Orleans (10) 90.0 (10) 60.0 (10) 73.3 (30) E. coli Baltimore 0 (70) 0 (57) 0 (57) 0 Atlanta 0 (58) 0 (50) 0 (49) 0 New Orleans- 0 (10) 0 (10) 0 (10) 0 Coagulase-positive Baltimore 40.0 (70) 42.1 (57) 40.4 (57) staphylococci Atlanta 44.8 (58) 56.0 (50) 40.8 (49) 43.7 (341) New Orleans (10) 80.0 (10) (10) 90.0 (30) a Percentage of retail units positive. Number of retail units. TABLE 8. Percentage of retail units positive for coliform organisms, E. coli, and coagulase-positive staphylococci in three geographical areas from plants operating under poor sanitary conditions 99% Con- Aemen Organism Area Regular Claw Lump Area mean fidence %) interval Coliform organisms Baltimore 60.0a (85)" 52.9 (85) 48.4 (85) 65.1 (725) Atlanta 71.3 (160) 79.3 (150) 63.1 (160) New Orleans (135) 90.4 (135) 85.0 (140) 88.5 (410) E. coli Baltimore 12.9 (85) 7.1 (85) 7.1 (85) 6.3 Atlanta 4.4 (160) 6.0 (150) 4.4 (160). (725) 3-8 New Orleans (135) 22.2 (135) 15.0 (140) 22.4 (410) Coagulase-positive Baltimore 64.7 (85) 65.9 (85) 51.8 (85) 55.6 (725) staphylococci Atlanta 56.9 (160) 60.7 (150) 40.6 (160) New Orleans (135) 83.0 (135) 81.4 (410) 82.0 (410) a Percentage of retail units positive. " Number of retail units.

9 waylous aay~~day 966 PHILLIPS AND PEELER APPL. MICROBIOL. TABLE 9. Comparison of APC results from samples time, and an average APC (geometric) of less produced on day of inspection and samples of a than 100,000/g in 93% of the plants, with 85% previous day's production of the plants below 50,000/g. Our findings No. of confirm the premise previously established by plants Surkiewicz et al. (6-9) that insanitary conditions during the processing of food products are Geometric Geomet ric having Source means, same means, pre- t means reflected in the bacteriological results of the test day vious previous finished product. > same day ACKNOWLEDGMENTS Regular ,000 (210)' 340,000(199) 3.82' 14/21 We thank the inspectors and microbiologists in Baltimore, Claw... 76,000 (120) 200,000 (103) 7.71' 11/12 Atlanta, New Orleans, and Districts for their full Lump... 45,000 (63) 120,000 (55)4.03' 5/8 cooperation and professional assistance, which were essential for the conduct of this survey. afinished product units per mean. b Significant at the a = 0.01 level. LITERATURE CITED handled many unsanitized objects during processing and continued picking or packing crabmeat without washing or sanitizing their hands. Picking and packing tables can also be a source of contamination. Puncochar and Pottinger (4) recommended that the tables be cleaned and sanitized each time the supply of crabs is exhausted. This procedure is seldom followed; if it were, two problems could be solved. (i) It would minimize bacterial buildup on the table surface, and (ii) it would allow for the rotation of crabs so that those at the bottom of a pile would not remain at room temperature for long periods of time. Although significant differences were observed between certain geographical areas, results of this survey indicate that crabmeat processors should be able to achieve a product with good microbiological quality by applying simple rules of sanitation. Plants operating under good sanitary conditions produced crabmeat with average MPN values (geometric) of less than 20 coliform organisms per g, no E. coli, coagulase-positive staphylococci average MPN values (geometric) of less than 30/g 93% of the 1. AOAC Official methods of analysis of the Association of Official Analytical Chemists, 11th ed. Washington, D.C. 2. Duncan, D. B Multiple range and multiple F tests. Biometrics 11: Ostle, B Statistics in research, 2nd ed. Iowa State University Press, Ames, Iowa. 4. Puncochar, J. F., and S. R. Pottinger Commercial production of meat from the blue crab (Callinectes sapidus). A study of sanitary requirements of handling operations and suggestions for technological improvement. U.S. Dept. Interior Fish and Wildlife Service, Commercial Fisheries TL8. 5. Slocum, G. G Bacteriology of crabmeat as related to factory sanitation. Ass. Food Drug Officials, U.S. Quart. Bull. 19: Surkiewicz, B. F Bacteriological survey of the frozen prepared foods industry. I. Frozen cream-type pies. Appl. Microbiol. 14: Surkiewicz, B. F., R. J. Groomes and A. P. Padron Bacteriological survey of the frozen prepared foods industry. III. Potato products. Appl. Microbiol. 15: Surkiewicz, B. F., R. J. Groomes, and L. R. Shelton, Jr Bacteriological survey of the frozen prepared foods industry. IV. Frozen breaded fish. Appl. Microbiol. 16: Surkiewicz, B. F., J. B. Hyndman, and M. V. Yancey Bacteriological survey of the frozen prepared foods industry. II. Frozen raw breaded shrimp. Appl. Microbiol. 15: Tobin, L. C., and C. S. McCleskey Bacteriological studies of fresh crabmeat. Food Res. 6: