Salmonella prevalence in seafood imported into Japan

A total of 353 samples of 29 types of seafood were tested for Salmonella prevalence and total microbial population. Salmonella enterica serotype Weltevreden was isolated from 2 of 47 black tiger prawn samples. The contamination levels of Salmonella were in a range of <30 to 40 most probable number per 100 g. In addition, one sample of black tiger prawns and two samples of white shrimp were positive for Salmonella invA gene on PCR assay. Although the mean aerobic bacterial count was greater than 4 log CFU/g in most of the sample types, those in the two Salmonella-isolated samples of black tiger prawn were 7.48 and 5.18 log CFU/g, respectively. These results indicate the possibility that shrimp and prawns contribute to foodborne infections. The improvement of seafood quality is an important issue, and the information on contamination by pathogens should be provided as feedback to the originating country, with the aim of increasing safety.     

A field study of the microbiological quality of fresh produce

The Centers for Disease Control and Prevention has reported that foodborne disease outbreaks associated with fruits and vegetables increased during the past decade. This study was conducted to characterize the routes of microbial contamination in produce and to identify areas of potential contamination from production through postharvest handling. We report here the levels of bacterial indicator organisms and the prevalence of selected pathogens in produce samples collected from the southern United States. A total of 398 produce samples (leafy greens, herbs, and cantaloupe) were collected through production and the packing shed and assayed by enumerative tests for total aerobic bacteria, total coliforms, total Enterococcus, and Escherichia coli. These samples also were analyzed for Salmonella, Listeria monocytogenes, and E. coli O157:H7. Microbiological methods were based on methods recommended by the U.S. Food and Drug Administration. For all leafy greens and herbs, geometric mean indicator levels ranged from 4.5 to 6.2 log CFU/g (aerobic plate count); less than 1 to 4.3 log CFU/g (coliforms and Enterococcus); and less than 1 to 1.5 log CFU/g (E. coli). In many cases, indicator levels remained relatively constant throughout the packing shed, particularly for mustard greens. However, for cilantro and parsley, total coliform levels increased during the packing process. For cantaloupe, microbial levels significantly increased from field through packing, with ranges of 6.4 to 7.0 log CFU/g (aerobic plate count); 2.1 to 4.3 log CFU/g (coliforms); 3.5 to 5.2 log CFU/g (Enterococcus); and less than 1 to 2.5 log CFU/g (E. coli). The prevalence of pathogens for all samples was 0, 0, and 0.7% (3 of 398) for L. monocytogenes, E. coli O157:H7, and Salmonella, respectively. This study demonstrates that each step from production to consumption may affect the microbial load of produce and reinforces government recommendations for ensuring a high-quality product.     

Bacteriological profile of raw, frozen chicken nuggets

The bacteriological profile of raw, frozen chicken nuggets manufactured at a chicken processing facility in Queensland, Australia, was determined. Chicken nuggets are manufactured by grinding poultry, adding premixes to incorporate spices, forming the meat to the desired size and shape, applying a batter and breading, freezing, and packaging. A total of 300 frozen batches were analyzed for aerobic plate count, Escherichia coli, and Salmonella over a period of 4 years. The mean of the aerobic plate count was 5.4 log CFU/g, and counts at the 90th, 95th, and 99th percentiles were 5.7, 5.9, and 6.5 log CFU/g, respectively. The maximum number of bacteria detected was 6.6 log CFU/g. E. coli prevalence was 47%, and of the positive samples, the mean was 1.9 log CFU/g; counts at the 90th, 95th, and 99th percentiles were 2.3, 2.4, and 2.8 log CFU/g, respectively. The maximum number of E. coli was 2.9 log CFU/g. The Salmonella prevalence was 8.7%, and 57.7% of these isolates were typed as Salmonella subspecies II 4,12,[27]:b:[e,n,x] (Sofia), a low-virulence serotype well adapted to Australian poultry flocks. There was a significant relationship (P < 0.05) between season and both aerobic plate counts and E. coli counts, and no correlation between E. coli counts and Salmonella prevalence. This study provides valuable data on the bacteriological quality of raw, frozen chicken nuggets.     

A national survey of the microbiological quality of beef carcasses and frozen boneless beef in Australia

The third national baseline microbiological survey of Australian beef carcasses and frozen boneless beef was conducted in 2004. Carcasses (n=1155) sampled at 27 slaughter establishments had a mean aerobic plate count (at 25 degrees C) of 1.3 log CFU/cm2. Escherichia coli was isolated from 8.0% of the cacasses, with a mean count of -0.8 log CFU/cm2 for positive samples. On samples from 24 boning (fabrication) plants (n=1082), the mean aerobic plate count for frozen boneless beef was 1.3 log CFU/g, and the mean count for the 1.8% of samples with detectable E. coli was 1.5 log CFU/g. E. coli O157: H7 was isolated from 1 of 1,143 carcasses and from 0 of 1082 boneless samples. Salmonella was isolated from 0 of 1155 carcasses and from 1 of 1082 samples of boneless product. No Campylobacter spp. were isolated from carcasses or boneless beef. Coagulase-positive staphylococci were isolated from 28.7% of beef carcasses and 20.3% of boneless beef samples, and positive samples had a mean count of 0.3 log CFU/cm2 and 0.8 log CFU/g, respectively.     

A survey of the microbiological quality of kangaroo carcasses processed for human consumption in two processing plants in Queensland, Australia

An investigation of the microbiological quality of kangaroo carcasses at two Queensland processing plants was carried out. A total of 836 whole muscle samples were taken, 801 from plant A and 35 from plant B. Samples were analyzed for aerobic bacteria, Escherichia coli, and Salmonella. The mean adjusted aerobic plate count (APC) was 2.8 log CFU/g, and counts at the 90th, 95th, and 99th percentiles were 4.2, 4.9, and 6.4 log CFU/g, respectively. The maximum number of bacteria recovered was 6.5 log CFU/g. E. coli was detected in 13.9% of samples, for which the adjusted mean was 0.7 log CFU/g, and counts at the 90th, 95th, and 99th percentiles were 1.4, 2.0, and 3.0 log CFU/g, respectively. Salmonella was detected in 0.84% of samples. There was no significant relationship (P < 0.05) between season and APC or E. coli count. There was a significant relationship (P < 0.001) between Salmonella prevalence and summer. The microbiological quality of Queensland kangaroo carcasses is similar to that obtained during other excision-based studies of kangaroo, wild boar, and beef carcasses.     

A national survey of the microbiological quality of retail raw meats in Australia

A national survey of the microbiology of meat (ground beef and diced lamb) at the retail level in Australia was undertaken. For ground beef samples (n = 360), the mean aerobic plate count (APC) was 5.79 log CFU/g, and Escherichia coli was detected in 17.8% of samples; the mean population for these positive samples was 1.49 log CFU/g. Enterobacteriaceae were detected in 96.9% of samples (mean for positive samples, 3.01 log CFU/g), and coagulase-positive staphylococci were detected in 28.1% of samples (mean for positive samples, 2.18 log CFU/g). For diced lamb samples (n = 360), the mean APC was 5.71 log CFU/g, and E. coli was detected in 16.7% of samples (mean for positive samples, 1.67 log CFU/g). Enterobacteriaceae were detected in 91.1% of samples (mean for positive samples, 2.85 log CFU/g), and coagulase-positive staphylococci were detected in 22.5% of samples (mean for positive samples, 2.34 log CFU/g). Salmonella was recovered from 4 (1.1%) of the 360 ground beef samples (isolates were Salmonella Typhimurium phage types), and E. coli O157 was recovered from 1 (0.3%) of 357 samples; Campylobacter and Clostridium perfringens were not recovered from any of the 91 and 94 samples tested, respectively. Salmonella was recovered from 2 (0.6%) of the 360 diced lamb samples (serovars were Salmonella Infantis and Salmonella Typhimurium), Campylobacter was recovered from 1 (1.1%) of 95 samples, and C. perfringens was recovered from 1 (1.1%) of 92 samples.     

A survey of the bacteriological quality of preroasted peanut, almond, cashew, hazelnut, and brazil nut kernels received into three Australian nut-processing facilities over a period of 3 years

There is little information about bacteriological quality of preroasted kernels available in the public domain. An investigation of the bacteriological quality of preroasted peanut, almond, cashew, hazelnut, and Brazil nut kernels received into three Australian nut-processing facilities was performed over a period of 3 years. A total of 836 samples were analyzed for aerobic plate count, and 921 samples for Salmonella and Escherichia coli. The 921 samples included 653 peanut, 100 cashew, 60 almond, 60 Brazil nut, and 48 hazelnut kernels. There was no E. coli detected in any sample. Salmonella subsp. II (Fremantle) was detected in one raw almond sample. The aerobic plate count percentages of positive samples with counts above the detection level of the plating method used (100 CFU/g) for peanuts, almonds, cashews, hazelnuts, and Brazil nuts were 84, 78, 74, 50, and 45%, respectively. Of the samples containing more than this detection limit, the means were 4.5, 4.4, 3.1, 2.5, and 3.8 log CFU/g respectively. Although roasted kernel quality was not within the scope of this survey, raw microbial bioload would be expected to reduce on roasting. The bacteriological quality of preroasted peanut, almond, cashew, hazelnut, and Brazil nut kernels received into nut-processing facilities in Australia does not appear to suggest a public health concern.     

Microbiological and color aspects of cooked sausages made from a standardized porcine blood cell concentrate

The objective of this study was to determine the potential for blood cell concentrates (BCCs) from pigs as an ingredient in food. Sausages were made for this study according to a basic recipe for a type of blood sausage that is common in Germany. First, sausages were produced with rind and kettle broth only, and different amounts (2.5 to 31%) of standardized blood cell concentrate (s-BCC) were added (15% table salt [NaCl] and 25% protein content). Then, sausages were made with whole blood and compared with s-BCC sausages; both the BCC and blood had been pretreated either with NaCl or curing salt (nitrite). The impact of BCC and blood on the color (La*b*) of these rind sausages was determined. Finally, blood sausages were made with 12% s-BCC and either natural spices or spice extracts. These sausages were investigated microbiologically and compared to customary commercial blood sausage products (with whole blood) in terms of aerobic plate count (APC), Enterobacteriaceae, sulfite-reducing anaerobic bacteria, coagulase-positive staphylococci, and spore-forming bacilli. The desired color parameters (L, 34.5; a*, 17.8; and b*, 10.6) were obtained with the addition of about 12% s-BCC. Curing the blood or BCC beforehand had no significant (P > 0.05) influence on the color. The microbial counts of both the blood (APC, 4.4 log CFU/g) and the natural spices (APC, 6.6 log CFU/g) were relatively high. The spices were responsible for the relatively high microbial counts in the sausages, particularly the bacilli (6.4 log CFU/g). However, these counts were comparable to those found in commercial blood sausages. The bacteria introduced into the sausage by the blood had no significant impact on the bacterial counts of the end product. The bacterial loads of the sausages produced with 12% s-BCC and spice extracts were significantly lower (APC and bacilli, 2.0 log CFU/g) than those of the other blood sausages (APC, -4.4 log CFU/g; bacilli, 3.2 to 4.0 log CFU/g).     

Effects of different disinfection treatments on the natural microbiota of lettuce

In this study, water and eight sanitizing solutions (vinegar at 6, 25, and 50%; acetic acid at 2 and 4%; peracetic acid at 80 ppm, sodium hypochlorite at 200 ppm, and sodium dichloroisocyanurate at 200 ppm) were compared in terms of their effectiveness against the natural microbiota of lettuce. All of the samples were kept in contact with the sanitizing solutions for 15 min, and the effectiveness of a sanitizing agent was evaluated on the basis of the number of decimal reductions of the total aerobic mesophilic count, the mold and yeast count, the total coliform count, and the Escherichia coli count. The average initial levels of these organisms in the samples were 6.94 log10 CFU/g for aerobic mesophilic microorganisms, 5.62 log10 CFU/g for molds and yeasts, and 3.25 log10 CFU/g for total coliforms. Of 10 samples analyzed, only 4 contained E. coli, and the average initial level of this microorganism in these 4 samples was 1.64 log10 CFU/g. Salmonella was not detected in any of the samples tested. The decimal reductions of the populations of aerobic mesophilic microorganisms, molds and yeasts, total coliforms, and E. coli were 0.78, 0.87, 0.82, and >0.14 log10 CFU/g, respectively, in water; 2.89, >3.41, >2.21, and >0.26 log10 CFU/g, respectively, in 50% vinegar; 2.42, >3.20, >1.99, and >0.26 log10 CFU/g, respectively, in 25% vinegar; 1.83, 2.57, 1.58, and >0.26 log10 CFU/g, respectively, in 6% vinegar; 3.91, >3.58, >2.25, and >0.26 log10 CFU/g, respectively, in 4% acetic acid; 3.37, >3.53, >2.25, and >0.26 log10 CFU/g, respectively, in 2% acetic acid; 1.85, 2.32, 1.44, and >0.20 log10 CFU/g, respectively, in 80 ppm of peracetic acid; 2.63, 2.75, 1.91, and >0.26 log10 CFU/g, respectively, in 200 ppm of sodium hypochlorite; and 3.23, >3.08, >1.95, and >0.26 log10 CFU/g, respectively, in 200 ppm of sodium dichloroisocyanurate. Statistical analysis of the results showed that the effectiveness levels for all of the sanitizing agents tested were equivalent to or higher than that for sodium hypochlorite at 200 ppm.     

Prevalence and antimicrobial susceptibility of major foodborne pathogens in imported seafood

Seafood is a leading commodity implicated in foodborne disease outbreaks in the United States. Seafood importation rose dramatically in the past 3 decades and now contributes to more than 80% of the total U.S. seafood supply. However, limited data are available on the microbiological safety of imported seafood. In this study, we obtained a total of 171 salmon, shrimp, and tilapia samples imported from 12 countries in three retail stores in Baton Rouge, LA. The total microbial population and the prevalence and antimicrobial susceptibilities of six major foodborne-pathogen genera (Campylobacter, Escherichia coli, Listeria, Salmonella, Shigella, and Vibrio) were determined. The aerobic plate counts (APC) for the 171 samples averaged 4.96 log CFU/g, with samples from Chile carrying the highest mean APC of 6.53 log CFU/g and fresh samples having a significantly higher mean APC than frozen ones (P < 0.0001). There were 27 samples (15.8%) with unacceptable microbiological quality (APC > 7 log CFU/g). By culture, no sample tested positive for Campylobacter coli, Shigella, or Vibrio vulnificus. Campylobacter jejuni and Salmonella enterica serovar Typhimurium were each recovered once from farm-raised tilapia from China. By PCR, 17.5 and 32.2% of the samples were positive for Salmonella and Shigella, respectively. The overall prevalence rates of other target bacteria were low, ranging from 4.1% for Listeria monocytogenes to 9.4% for E. coli. All of the Vibrio parahaemolyticus isolates recovered were from shrimp, and 63.3% showed intermediate resistance to ampicillin. Both C. jejuni isolates possessed a rare resistance to gentamicin, while 75% of L. monocytogenes isolates were resistant to nitrofurantoin. Taken together, these findings suggest potential food safety hazards associated with imported seafood and warrant further large-scale studies.     

ATP bioluminescence assay for estimation of microbial populations of fresh-cut melon

Estimation of microbial numbers in foods by conventional microbiological techniques takes days, so there is a need for faster methods that can give results in minutes. Research was undertaken to investigate the use of bioluminescent ATP determination and a firefly luciferase assay to estimate the initial population of aerobic mesophilic bacteria on fresh-cut melons immediately after preparation and during storage at 5 or 15 degrees C for up to 12 days. Populations of aerobic mesophilic bacteria on fresh-cut cantaloupe prepared immediately from unsanitized whole melons averaged 3.42 log CFU/g, corresponding to an ATP value of 5.40 log fg/g. Populations for fresh-cut honeydew prepared from unsanitized whole melon averaged 1.97 log CFU/g, corresponding an ATP value of 3.94 log fg/g. Fresh-cut pieces prepared from cantaloupe or honeydew melons sanitized with either chlorine (200 ppm free chlorine) or hydrogen peroxide (2.5%) had similar ATP values: 3.1 log fg/g (corresponding to bacterial counts 1.7 log CFU/g) for cantaloupes and 2.6 log fg/g (corresponding to bacterial counts of 0.48 CFU/g) for fresh-cut honeydew. Positive linear correlations for ATP concentrations and microbial populations were found for fresh-cut cantaloupe (R2 = 0.99) and honeydew R2 = 0.95) during storage at 5 degrees C for up to 12 days. ATP values in fresh-cut melons inoculated with either aerobic mesophilic bacteria or yeast and mold were significantly higher (P < 0.05) than control values and parallel total plate counts on plate count agar. Results of this study indicate that the bioluminescent ATP assay can be used to monitor total microbial populations on fresh-cut melon after preparation and during storage for quality control purposes to establish specific sell-by or consume-by dates.     

Microbiological quality and safety of ready-to-eat street-vended foods in Johannesburg, South Africa

Fifty-one ready-to-eat street foods, 18 dishwater, and 18 surface swab samples were collected from six vendors in Johannesburg, South Africa. Food temperatures were recorded at the time of sampling. Standard methods were used to determine aerobic plate counts (APCs), spore counts (SCs), and Enterobacteriaceae counts (ECs) for food samples as well as coliform counts (CCs) for water and swab samples. In addition, Petrifilm Escherichia coli count (PC) plates were used for the enumeration of coliforms in food, water, and swab samples. The presence of selected foodborne pathogens in the food samples as well as the presence of nonpathogenic E. coli 1 (in food and water samples) was also tested for. Predominant colonies isolated from APC plates were characterized to the genus level. Holding temperatures for cooked meats and gravies ranged from 42.0 to 94.0 degrees C, and those for uncooked salads ranged from 29.0 to 39.0 degrees C. Mean APC values of 3.4 (+/-0.4) log CFU/g, 4.0 (+/-1.2) log CFU/ml, and 2.1 (+/-0.4) log CFU/25 cm2 were obtained for food, water, and swab samples, respectively. Mean SC values of 1.6 (+/-0.2) log CFU/g and 1.5 (+/-0.3) log CFU/25 cm2 were obtained for food and swab samples, respectively. A mean EC value of 2.0 (+/-0.4) log CFU/g for food samples and mean CC values of 2.5 (+/-0.3) log CFU/ml and 1.3 (+/-0.3) log CFU/25 cm2 for water and swab samples, respectively, were determined. Mean PC values of 1.6 (+/-0.1) log CFU/g, 1.9 (+/-0.6) log CFU/ml, and 1.4 (+/-0.4) log CFU/25 cm2 were determined for food, water, and swab samples, respectively. Bacillus cereus was detected in 22%, Clostridium perfringens in 16%, Salmonella spp. in 2%, and E. coli (non-O157:H+) in 2% of the 51 food samples. E. coli was found in 14 water samples (78%) and in 3 food samples (6%). Campylobacter spp., Listeria monocytogenes, Staphylococcus aureus, Vibrio cholerae, and Yersinia enterocolitica were also tested for in the food samples, but they were not detected. The 340 isolates obtained from APC plates for food, water, and swab samples were predominantly Bacillus spp., Micrococcus spp., and Staphylococcus spp. for all three sample types. It was concluded that the foods analyzed in this study were of acceptable quality and safety.     

Radiation processing for elimination of Salmonella typhimurium from inoculated seeds used for sprout making in India and effect of irradiation on germination of seeds

The effect of radiation processing on the germination of the sprout seeds mung (Phaseolus aureus), matki (Phaseolus aconitifolius), chana (Cicer arietinum), and vatana (Pisum sativum) in terms of percent germination, germination yield, sprout length, vitamin C content, and texture was investigated. Gradual decreases in the percent germination, germination yield, and sprout length with increases in radiation dose (0.5 to 2.0 kGy) were observed. Vitamin C content and texture remained unaffected for the seeds treated with doses of up to 2 kGy. To determine the efficacy of radiation treatment in elimination of foodborne pathogens, seeds inoculated with 4 log CFU/g of Salmonella Typhimurium were treated with radiation doses of 1 and 2 kGy. A reduction in counts of Salmonella Typhimurium in inoculated seeds after radiation treatment was observed. A radiation dose of 2 kGy resulted in the complete elimination of 4 log CFU/g of Salmonella Typhimurium from the inoculated seeds. However, on sprouting for 48 h, the count of Salmonella Typhimurium reached 8 log CFU/g for the control seeds and the seeds treated with a 1-kGy radiation dose. The aerobic plate counts for seeds were 2.0 to 2.6 log CFU/g, which were reduced to 0.9 to 1.2 log CFU/g on treatment with a 2-kGy radiation dose. On sprouting for 48 h, the aerobic plate count reached 8 log CFU/g for both the control and radiation-treated seeds. The study demonstrates that irradiation can control bacterial levels on seeds but not contamination introduced during posttreatment handling. Therefore, radiation processing of the final product (sprouts) is recommended, rather than of the seeds.     

Impacts of broadband and selected infrared wavelength treatments on inactivation of microbes on rough rice

This study investigated the effects of broadband and selected infrared (IR) wavelength treatments of rough rice on microbial inactivation. Rough rice was treated at different IR wavelengths and product-to-emitter distances (110, 275, and 440 mm) followed by tempering at 60°C for 4 hr. The total mold and aerobic plate counts (APC) on non-treated and treated samples were determined. Significant total mold reductions of 1.14 and 3.11 log CFU/g were obtained after IR heating using broadband and selected wavelengths, respectively (p < .05). The most significant reduction of APC using selected IR wavelength was 1.09 log CFU/g; the broadband IR wavelength had no effect on the mean APC. The IR treatments followed by tempering step resulted in greater reductions of total mold counts and APC (4.03 and 3.50 log CFU/g) in comparison to IR treatments without tempering (3.11 and 1.09 log CFU/g). Overall, bacteria showed more resistance to IR treatments than molds.     

Microbiological quality of rabbit meat

World rabbit meat production is estimated to be over 1 million tons, and Spain is the third largest producer. Although rabbit meat is marketed and consumed worldwide, information on microbiological quality is very scarce. Here, we report indicator organisms, spoilage flora, sensory quality, and some physicochemical traits of 24 h postmortem chilled rabbit carcasses and prepackaged rabbit meat stored chilled in air for 0 to 3 days at the retail level. The mean total bacterial count (4.01 +/- 0.48 log CFU/g) for carcasses dressed at a small abattoir by a manual process was significantly lower (P < 0.05) than that (4.96 +/- 0.90 log CFU/g) for carcasses dressed at a large abattoir in automated slaughter lines. Both groups of carcasses had mean pH values of 5.98. The dominant contaminants on carcasses from the small abattoir were Pseudomonas, lactic acid bacteria, and yeasts. These microorganisms and Brochothrix thermosphacta were dominant on carcasses from the large abattoir. On prepacked hind legs (pH 6.26 +/- 0.18) stored at -1 to +1 degree C (supermarket 1), mean aerobic mesophilic count was 5.87 +/- 1.03 log CFU/g, and the major microbial groups were Pseudomonas, yeasts, lactic acid bacteria, and B. thermosphacta. On prepacked whole carcasses (pH 6.37 +/- 0.18) displayed at -1 to +5 degrees C (supermarket 2), mean aerobic mesophilic count was 6.60 +/- 1.18 and the same microbial groups were dominant. Relative Escherichia coli incidence was supermarket 2 > large abattoir > supermarket 1 > small abattoir. Overall, low numbers of coliforms, Enterobacteriaceae, psychrotrophic clostridia, coagulase-positive staphylococci, and molds were found. Sensory scores, pH values, and L-lactic acid content differentiated fresh carcasses from retail samples. Data obtained suggest that the microflora of chilled rabbit meat are different from those found on the meat of other animals.     

Microbiological status of fresh beef cuts

Fresh beef samples (n = 1,022) obtained from two processing plants in the Midwest (July to December 2003) were analyzed for levels of microbial populations (total aerobic plate count, total coliform count, and Escherichia coli count) and for the presence or absence of E. coli O157:H7 and Salmonella. A fresh beef cut sample was a 360-g composite of 6-g portions excised from the surface of 60 individual representative cuts in a production lot. Samples of fresh beef cuts yielded levels of 4.0 to 6.2, 1.1 to 1.8, and 0.8 to 1.0 log CFU/g for total aerobic plate count, total coliform count, and E. coli count, respectively. There did not appear to be substantial differences or obvious trends in bacterial populations on different cuts. These data may be useful in establishing a baseline or a benchmark of microbiological levels of contamination of beef cuts. Mean incidence rates of E. coli O157:H7 and Salmonella on raw beef cuts were 0.3 and 2.2%, respectively. Of the 1,022 samples analyzed, cuts testing positive for E. coli O157:H7 included top sirloin butt (0.9%) and butt, ball tip (2.1%) and for Salmonella included short loins (3.4%), strip loins (9.6%), rib eye roll (0.8%), shoulder clod (3.4%), and clod, top blade (1.8%). These data provide evidence of noticeable incidence of pathogens on whole muscle beef and raise the importance of such contamination on product that may be mechanically tenderized. Levels of total aerobic plate count, total coliform count, and E. coli count did not (P > or = 0.05) appear to be associated with the presence of E. coli O157:H7 and Salmonella on fresh beef cuts. E. O157:H7 was exclusively isolated from cuts derived from the sirloin area of the carcass. Salmonella was exclusively isolated from cuts derived from the chuck, rib, and loin areas of the carcass. Results of this study suggest that contamination of beef cuts may be influenced by the region of the carcass from which they are derived.     

Distribution and prevalence of airborne microorganisms in three commercial poultry processing plants

Airborne microbial contaminants and indicator organisms were monitored within three poultry processing plants (plants A, B, and C). In total, 15 cubic feet (c.f.) of air was sampled per location during 15 visits to each plant and quantitatively analyzed for total mesophilic and psychrophilic aerobic counts, thermophilic campylobacters, Escherichia coli, and Enterobacteriaceae. The prevalence of Salmonella spp. in air samples was also evaluated. Significant reductions in total aerobic counts were observed between defeathering and evisceration areas of the three plants (P < 0.05). Mesophilic plate counts were highest in the defeathering areas of all plants compared to equivalent psychrophilic plate counts. Enterobacteriaceae counts were highest in the defeathering areas of all three plants with counts of log10 1.63, 1.53, and 1.18 CFU/15 c.f. recovered in plants A, B, and C, respectively. E. coli enumerated from air samples in the defeathering areas exhibited a similar trend to those obtained for Enterobacteriaceae with log10 1.67, 1.58, and 1.18 CFU for plants A, B, and C, respectively. Thermophilic campylobacters were most frequently isolated from samples in the defeathering areas followed by the evisceration areas. The highest mean counts of the organism were observed in plant A at 21 CFU/15 c.f. sample with plants B and C at 9 and 8 CFU/sample, respectively. With the exception of low levels of Enterobacteriaceae recovered from samples in the on-line air chill in plant A, E. coli, Enterobacteriaceae, or Campylobacter spp. were not isolated from samples in postevisceration sites in any of the plants examined. Salmonella spp. were not recovered from any samples during the course of the investigation.     

Assessment of Microbiological Quality of Some Gamma Irradiated Indian Spices

Irradiated (10 kGy) and unirradiated pre-packed whole and ground spices including black pepper, red chilli, and turmeric were examined by six different laboratories for microbiological quality. No colony forming units (CFU) were reported in the largest quantity of irradiated spices used in the study by three out of six laboratories. The other three laboratories reported counts ranging between 0–90 CFU/g in irradiated samples. None of the six laboratories reported the presence of E. coli or B. cereus in the spices exposed to gamma irradiation. These data suggest that a standard plate count of 0–100 CFU/g and a count of zero CFU/g for E. coli and B. cereus be fixed for spices exposed to a 10 kGy dose of gamma rays.     

Inhibitory effect of mixture herbs/spices on formation of heterocyclic amines and mutagenic activity of grilled beef

ABSTRACT

Natural antioxidants in spices and herbs have attracted considerable attention as potential inhibitors against the formation of mutagenic heterocyclic amines (HCAs) in heat-processed meat. In this study, the inhibitory activity of four spices/herbs and their mixtures on HCAs formation in grilled beef were examined. A simplex centroid mixture design with four components comprising turmeric, curry leaf, torch ginger and lemon grass in 19 different proportions were applied on beef samples before grilling at 240 ºC for 10 min. The HCAs were extracted from the samples using solid phase extraction (SPE) method and analysed using Liquid chromatography mass spectrometry LC-MS/MS. All spices/herbs in single or mixture forms were found to reduce total HCA concentrations in marinated grilled beef ranging from 21.2% for beef marinated with curry leaf to 94.7% for the combination of turmeric and lemon grass (50:50 w/w). At the optimum marinade formula (turmeric: lemon grass 52.4%: 47.6%), concentration of 2-amino-3-methylimidazo[4,5-f]quinolone (IQ), 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), Harman, Norharman and AαC were 2.2, 1.4, 0.5, 2.8 and 1.2 ng/g, respectively. The results of the mutagenic activity demonstrated that this optimised marinade formula significantly (p < 0.05) diminished mutagenicity of marinated grilled beef in bacterial Ames test.     

Microbiological survey of retail herbs and spices from Mexican markets

In the present study, 304 samples of herbs and spices (garlic powder, cumin seeds, black pepper, oregano, and bay leaves) widely used in Mexico were analyzed for the presence of Bacillus cereus, Salmonella Typhi, Shigella dysenteriae, Escherichia coli, total and fecal coliforms, total mesophilic aerobic organisms, and fungi. Samples were nonpackaged or packaged in polyethylene bags or glass containers. High levels (10(5) to 10(7) CFU/g) of mesophilic aerobic microorganisms were found in most of the samples of garlic powder, cumin seed, and black pepper. Lower levels (<102 CFU/g) were found in oregano and bay leaves. Total and fecal coliforms counts were dependent on the type of packaging. More than 70% of the polyethylene-packaged samples had less than 10(3) CFU/g of microorganisms. Glass and nonpackaged spices showed lower levels of these microorganisms. B. cereus was present in 32 samples of which most were polyethylene packaged. The other pathogenic bacteria were not detected. Aspergillus niger was detected in 29% of the samples, Rhizopus sp. in 19%, and Penicillum sp. and Cunninghamella in 8%.