Profile of selected bacterial counts and Salmonella prevalence on raw poultry in a poultry slaughter establishment.

The USDA Food Safety and Inspection Service determined populations of bacteria on poultry during processing at a slaughter plant in Puerto Rico in November and December 1987. The plant was selected because of its management's willingness to support important changes in equipment and processing procedures. The plant was representative of modern slaughter facilities. Eight-hundred samples were collected over 20 consecutive 8-hour days of operation from 5 sites in the processing plant. Results indicated that slaughter, dressing, and chilling practices significantly decreased the bacterial contamination on poultry carcasses, as determined by counts of aerobic bacteria, Enterobacteriaceae, and Escherichia coli. Salmonella was not enumerated; rather, it was determined to be present or absent by culturing almost the entire rinse. The prevalence of Salmonella in the study decreased during evisceration, then increased during immersion chilling.     

The use of neck skin for microbial process control of fresh poultry meat using the bioluminescence method

In this study comparative investigations of the total viable counts of bacteria and viable counts of Enterobacteriaceae with the ATP content were carried out on 70 poultry carcasses and neck skins thereof. The results revealed a correlation of total viable counts on the neck skin and on the carcass sample. Therefore the examination on total viable counts of neck skin is able to give results on the respective load of the carcass (coefficient of correlation (r) = 0.85 and coefficient of determination (R2) = 0.71). This only applies, however, to a slaughter technology at which the poultry hangs up site down with the neck skin to the bottom. The results of the ATP investigation expressed in Relative Light Units (RLU) in a bioluminescence method and total viable counts of neck skin samples are correlated (r = 0.85; R2 = 0.72). Lower values for r and R2 were estimated for RLU/Enterobacteriaceae on neck skin (r = 0.64; R2 = 0.41), for RLU/total viable counts on the carcass (r = 0.66; R2 = 0.46) and for RLU/Enterobacteriaceae on the carcass (r = 0.33; R2 = 0.11). To estimate the hygiene status in poultry slaughtery, sampling from the neck skin can replace the sampling on the whole carcass The bioluminescence method is suitable to replace the determination of total viable counts in the context of in-house hygiene supervision. However, this method seemed to be less reliable to predict the Enterobacteriaceae counts.     

Effects of chlorination of chill water on the bacteriologic profile of raw chicken carcasses and giblets.

In March 1989, the USDA Food Safety and Inspection Service sampled raw chicken carcasses and giblets at a federally inspected slaughter establishment in Puerto Rico to determine the effects of adding chlorine to carcass and giblet chill water on bacterial contents of raw poultry products. Over four 8-hour workdays, 200 carcass rinse samples were collected at 3 sites in the establishment; 39 giblet rinse samples were collected at 1 site. Analyses of the carcass rinse samples indicated that carcasses had average aerobe plate counts of log10 3.20 before chilling and 2.51 after chilling; Enterobacteriaceae counts of log10 2.57 before chilling and 1.75 after chilling; and Escherichia coli counts of log10 2.04 before chilling and 1.20 after chilling. Salmonellae were found on 43% of the carcasses before chilling and on 46% after chilling. Analyses of the giblet and neck rinse samples indicated that raw giblets and necks after chilling had average aerobe plate count of log10 3.49, Enterobacteriaceae count of log10 2.57, and E coli count of log10 1.06. Salmonellae were found on 12% of the giblets and necks sampled. Results compared favorably with giblet and neck rinse sample results obtained during a baseline sampling study in November and December 1987. The baseline results indicated aerobe plate count of log10 3.72; Enterobacteriaceae count of log10 2.90; E coli count of log10 1.14; and salmonellae on 69% of the giblets and necks sampled. Placing raw chicken carcasses in chlorinated chill water reduced aerobe, Enterobacteriaceae, and E coli plate counts. Prevalence of carcasses with salmonellae remained nearly the same.(ABSTRACT TRUNCATED AT 250 WORDS)     

Comparative Study of Microbiological Quality of Raw Poultry Meat at Various Seasons and for Different Slaughtering Processes in Casablanca (Morocco)

The aim of the present study was to evaluate the bacterial quality of chicken (n = 96) and turkey (n = 96) marketed in Casablanca, Morocco. Poultry samples (n = 192) were collected randomly from traditional shops and supermarkets during 2 sampling periods (hot and cold seasons). The samples were analyzed for the presence and counts of various bacteria. Results indicated that aerobic plate counts and fecal coliforms were particularly high in all the samples analyzed. Escherichia coli, coagulase-positive Staphylococcus, Clostridium perfringens, Salmonella, and Listeria monocytogenes were detected, respectively, in 48.4, 10.4, 7.2, 1.6, and 0.5% of the poultry meat samples. The chicken and turkey samples contained, respectively, 25 and 33.3% of bacteria above the maximum limits established by the Moroccan regulatory standards. The highest bacterial counts in poultry meat product samples were recorded with the traditional slaughtering process during the hot season (P < 0.05). These high levels of microbial contamination and occurrence of pathogenic bacteria reflect the poor hygienic quality of poultry meat under these conditions.     

Bacterial Populations of Broiler Carcasses Washed in Mixtures of Potassium Hydroxide and Lauric Acid

The bactericidal effect of mixtures of KOH and lauric acid (LA) on the microflora of broiler carcasses was examined. Carcasses were washed by shaking in KOH-LA for 1 min on a mechanical shaker. In one set of experiments, the population of bacteria recovered from carcasses following each of 3 successive washes in 1.0% KOH-2.0% LA or in distilled water (control) was enumerated. The number of total plate count bacteria, Campylobacter, and Escherichia coli in aliquots of whole-carcass-rinses of the washed carcasses was determined. Results indicated that fewer bacteria were generally recovered from carcasses after each successive wash in KOH-LA or distilled water, but significantly fewer bacteria were recovered from carcasses washed in KOH-LA than from carcasses washed in distilled water. Bacteria recovered from carcasses after the first and third wash in KOH-LA were identified using the MIDI Sherlock Microbial Identification System. Gram-positive and gram-negative bacteria were identified in the bacterial flora of carcasses washed once in KOH-LA; however, only gram-positive cocci were identified in the bacterial flora of carcasses washed 3 times in KOH-LA. Additional experiments were performed to compare the number of bacteria recovered from carcasses washed 2 times in 0.25% KOH-0.5% LA, 0.5% KOH-1.0% LA, or 1.0% KOH-2.0% LA or in distilled water (control). Results indicated that significantly fewer bacteria were recovered from carcasses washed in higher concentrations of KOH-LA than from carcasses washed in lower concentrations of KOH-LA. Findings from these experiments show that washing carcasses in KOH-LA can reduce carcass contamination by bacteria responsible for human foodborne diseases and spoilage of fresh poultry.     

Effect of ultrasonic treatment during cleaning on the microbiological condition of poultry transport crates

1. Small sections cut from commercial crates used to transport live poultry to the processing plant were artificially contaminated with effluent taken from a commercial crate-cleaning system. 2. Laboratory trials, involving the immersion of these sections in an ultrasonic water bath (4 kW energy) showed that aerobic plate counts (APC) and counts of Enterobacteriaceae were progressively reduced as the immersion time was increased from 0 to 120 s and the water temperature raised from 35 to 58 degrees C. 3. In subsequent trials at a processing plant, using commercially cleaned crates, there was relatively little effect of ultrasound (or pressure washing) on the biofilm present. However, ultrasonic treatment in combination with an immersion temperature of 60 degrees C reduced counts of Enterobacteriaceae to below the detection limit (log(10) 2.3 cfu) within 1 to 3 min, while APC were reduced by >2 log(10) units after 3 min. 4. It was concluded that ultrasonic treatment has a possible role in the crate-cleaning process, when used in conjunction with higher immersion temperatures. In this way, it could contribute significantly to hygiene control.     

Treatment of fresh poultry carcases with emulsions of glycerol monocaprate (monocaprin) to reduce contamination with Campylobacter and psychrotrophic bacteria

1. A previous study has shown that emulsions of monocaprin in citrate lactate buffer at pH 4·1-4·3 are highly active in killing Campylobacter in water, where they reduce viable bacterial counts by more than 6 log(10) colony forming units (cfu) in 1 min at a concentration of 1·25 mM (0·03%). 2. The present study was carried out to evaluate whether monocaprin emulsions could be used to kill Campylobacter on raw poultry. 3. It was shown that immersion of naturally contaminated chicken legs in 20 mM (0·5%) monocaprin emulsion at pH 4·1 for 1 min at 20°C reduced the number of Campylobacter by 2·0 to 2·7 log(10) cfu. Pre-chill dipping of whole carcases into 20 mM monocaprin emulsion in the slaughterhouse also caused a significant reduction in Campylobacter contamination. 4. Immersion in monocaprin emulsions at pH 4·1 was also assessed as a means to reduce the number of psychrotrophic spoilage bacteria. There were lower psychrotrophic bacteria counts on treated chicken parts than on untreated controls after storage at 3°C for up to 14 d. 5. Immersion in emulsions of monocaprin, which is a natural lipid classified as GRAS, may be a feasible method to reduce the number of Campylobacter and spoilage bacteria on raw poultry. This method could reduce the risk of human exposure to Campylobacter, and at the same time increase the shelf-life of poultry products.     

Effect of Sand and Shaking Duration on the Recovery of Aerobic Bacteria,Coliforms, and Escherichia coli from Prechill Broiler Whole Carcass Rinsates

Broilers entering a processing facility can be contaminated with bacteria internally, externally, or both, and additional contamination may occur during processing. Although processing generally reduces the bacterial load on a carcass, it does not eliminate all carcass bacterial contaminants. Processing plant personnel sample carcasses daily to determine overall carcass contamination using the whole carcass rinse procedure. The objective of this study was to evaluate the potential benefit of adding sand to the whole carcass rinse and extending shaking (rinsing) duration on the recovery of bacteria from broiler carcasses. Eviscerated broiler carcasses were obtained from a commercial processing plant before the prechill final wash. Carcasses were rinsed in peptone or peptone with sand for 1 and 4 min. Rinsates were analyzed for aerobic plate count, coliforms, and Escherichia coli. Bacterial levels recovered from rinsates with sand were significantly higher than levels recovered from the peptone-only rinsates, but the increase in recovery was relatively small at 0.6 log₁₀ cfu/mL of rinsate. There was no significant improvement in bacterial recovery when shaking duration was increased from 1 to 4 min for either rinse treatment.     

Microbiological baseline study of poultry slaughtered in provincially inspected abattoirs in Alberta, Canada

Studies to determine baseline levels of microbial contaminants and foodborne bacterial pathogens are needed to evaluate the effectiveness of Hazard Analysis Critical Control Point (HACCP) programs, Good Manufacturing/Production Practices, and various interventions. In 2004 and 2005 poultry carcass rinses from provincially inspected abattoirs in Alberta, Canada, were tested to determine the levels of aerobic plate count bacteria, coliform bacteria, and generic Escherichia coli, the prevalence and levels of Campylobacter spp., and the prevalence of Salmonella spp. and Shiga toxin-producing E. coli (STEC). Samples were collected from 3 high volume and 62 low volume abbatoirs. All samples (1296) were positive for aerobic plate count bacteria, with 98.8% of samples having counts of 100 000 or less colony forming units (CFU)/cm². Coliform bacteria were isolated from 99.7% of the 1296 carcasses and were recovered at levels of ≤ 1000 CFU/cm² for 98.3% of the samples. Generic E. coli were recovered from 99.1% of the 1296 carcasses at levels of ≤ 1000 CFU/cm² for 98.6% of the samples. Seventy five percent of 1234 samples that were tested for Campylobacter were positive; 37.5% of 1295 samples that were tested for Salmonella were positive; and only 2 of 1296 samples tested for STEC were positive (0.15%).     

Simulation model for Campylobacter cross-contamination during poultry processing at slaughterhouses

Broiler meat is regarded as the most common source of Campylobacter infection and risk management measures are required to reduce broiler meat contamination. Among the quantitative risk assessments for Campylobacter in broiler meat, evaluation of the poultry processing stage is particularly important for predicting the contamination level of broiler meat and the effects of control measures. In this study, we built a simulation model for cross‐contamination during poultry processing focusing on Campylobacter contamination at the individual carcass level. Using this model, we examined changes in the prevalence of contaminated carcasses and the number of Campylobacter per carcass after processing. As a result, it was found that the prevalence and number of Campylobacter after processing were largely influenced by the number of Campylobacter on the contaminated carcasses before processing. In the baseline model, where it was assumed that the mean number of Campylobacter on contaminated carcasses before processing was 4.7 log₁₀ cfu per carcass, the prevalence after processing was less than that before processing. Although the median value of Campylobacter on contaminated carcasses was reduced after processing, the distributions after processing became wider and the upper limit of the 95% credible interval of Campylobacter on contaminated carcasses remained elevated. The individual‐based simulation model can trace individual level changes considering discrete interactions, while models tracing mean values cannot handle these interactions in detail. The individual‐based approach is considered useful for modelling cross‐contamination among individual carcasses during poultry processing.     

Effect of spray-chilling on quality of beef from lean and fatter carcasses

Carcasses from five trim cows and five choice steers were used to study the effects of spray-chilling on cooler shrink, chill rate, purge loss from vacuum-packaged cuts, cook loss, shear values and bacterial growth. Spray-chilling reduced cooler shrink but had no effect on chill rate, purge loss from vacuum-packaged cuts, cook loss or shear values. Aerobes, facultative anaerobes, aerobic psychrotrophs, facultative anaerobic psychrotrophs and lactic acid bacteria all tended to be higher on rounds from spray-chilled sides. Leaner (and lighter) cow carcasses chilled faster and had lost a higher percentage of their weight at 24 h than fatter and heavier steer carcasses. The leaner carcasses had higher bacterial counts initially and throughout storage. This difference may have been due to differences in the level of initial contamination during dressing and not due to the carcasses' leanness. Purge-weight loss for each carcass increased and cooking weight loss decreased with increased storage times, making the total weight loss from meat aged 5 vs 10 wk similar.     

Microbiological evaluation of groups of beef carcasses: heifers and steers.

Numbers of mesophilic bacteria were estimated on carcasses of 25 heifers and 25 steers of beef breeds in a modern, high-line-speed abattoir. One side of each carcass from each sex was sampled at the end of the kill-floor, before the carcass wash, on each of 25 visits. Two adjacent excision samples (5 x 5 x 0.5 cm) were taken from each of ten sites and processed for automatic enumeration of aerobic bacteria on hydrophobic grid membrane filters. The effects of sex and carcass weight on bacterial counts were examined. Groups of carcasses were examined to determine the sample size required for future assessments of kill-floor hygiene. The log10 of the most probable number of growth units (MPNGU)/cm2 did not differ significantly between heifers and steers (average over the ten sites of 2.2) and there was no effect of carcass weight on bacterial counts for nine of the ten sites. There were, however, highly significant (p < 0.001) differences in the counts between sites and the counts from the ten sites clustered into five homogenous groups. The between-carcass component of variation at a site was generally larger than the within-carcass component. We conclude that, to estimate the mean log10 MPNGU/cm2 at a site to within +/- 0.5 units, future group-carcass evaluations require about 200 samples from 10 (two adjacent samples/site) or 20 carcasses (one sample/site).     

Bacterial contamination of processed poultry

Results from the bacteriological examination of uneviscerated, cooled eviscerated, and frozen eviscerated poultry carcasses from six different processing plants are presented. Eighty‐three per cent of the uneviscerated carcasses had total bacterial counts (on nutrient agar incubated at 22° C for 3 d) of less than 250,000 on a 16 cm² area of breast skin. The relative percentages for cooled and frozen eviscerated carcasses were 65.4 and 64.7 respectively. Over 90 per cent of the uneviscerated and frozen eviscerated carcasses had coli‐aerogenes counts of less than 1000 per 16 cm². Only 59.6 per cent of the cooled eviscerated carcasses were in this category. The cooled eviscerated carcasses carried more faecal streptococci than the uneviscerated and frozen eviscerated (79.8, 92.4 and 93.0 per cent respectively had less than 10,000 streptococci per 16 cm²). Of all carcasses, 66.8 per cent carried less than 100 Staphylococcus aureus per 16 cm² while 3.2 per cent carried more than 1000. A regression of total count on nutrient agar on the counts on the selective media showed that none of the regression or correlation coefficients for the uneviscerated carcasses was significant; for the cooled eviscerated carcasses (all plants) and the frozen eviscerated carcasses (plant F), both the coli‐aerogenes and faecal streptococcal counts were significantly correlated.     

The effect of lactic acid sprays on Campylobacter jejuni inoculated onto poultry carcasses.

Spraying poultry carcasses with 1% lactic acid 10 min after inoculation with Campylobacter jejuni, resulted in a significant reduction in the number of the bacteria after 4 h at 4 degrees C. Some of the inoculated cells, however, survived for at least 144 h. Spraying 10 min after inoculation with 2% lactic acid, totally eliminated all inoculated C. jejuni within 24 h. On the other hand, spraying 24 h after inoculation, with either 1% or 2% lactic acid did not eliminate all the bacteria. Inoculated C. jejuni on poultry carcasses not sprayed with lactic acid, survived at 4 degrees C throughout the sampling period (up to 144 h) and showed little tendency to decrease in number even when the carcasses started to deteriorate. Resident campylobacters on poultry carcasses were significantly reduced by the lactic acid treatment. Frozen and thawed chickens appeared to show a graying of the skins immediately after spraying with lactic acid, slightly stronger with 2% lactic acid, but the colour reverted to normal after 24 h. We were not able to observe any colour change on the fresh broiler chickens after lactic acid treatment. Our results indicated that lactic acid had a significant bactericidal effect on C. jejuni on both naturally and artificially contaminated poultry carcasses. This effect, however, became manifest only several hours after acid treatment.     

Effects of countercurrent scalding and postscald spray on the bacteriologic profile of raw chicken carcasses.

In June and September 1988, the USDA Food Safety and Inspection Service sampled raw chicken carcasses at a federally inspected slaughter establishment in Puerto Rico to determine the effects of changing the scalding equipment on bacterial contents of raw poultry products. The scalding equipment was changed to a countercurrent configuration, with a postscald hot-water rinse cabinet that sprayed carcasses as they exited the scalder. Analysis of 250 carcass-rinse samples collected at preevisceration, prechill, and postchill sites over 7 days indicated that carcasses had mean aerobe plate counts of log(10)3.73 before evisceration, 3.18 before chilling, and 2.87 after chilling; Enterobacteriaceae counts of log(10)2.70 before evisceration, 2.25 before chilling, and 1.56 after chilling; and Escherichia coli counts of log(10)2.09 before evisceration, 1.61 before chilling, and 0.89 after chilling. Salmonellae were found on 24% of the carcasses before evisceration, on 28% before chilling, and on 49% after chilling. Although bacterial count reductions were significant at all 3 sites, the proportion of carcasses contaminated with salmonellae in this study was higher at the postchill than prechill site (49 vs 28%). This no doubt was caused by cross-contamination in the chiller. These percentages indicated that although simple scalder changes contributed substantially to the improvement of the bacterial quality of chicken carcasses, additional interventions in the chilling process (such as chlorination of chill water) are important to control cross-contamination and to preserve the positive effects obtained by the scalder changes.     

The effect of different on-line dressing practices on microbiological and visible contamination of lamb carcasses

Three dressing practices were assessed in traditional lamb carcass dressing systems for their ability to improve control of microbiological and visible contamination. The routine removal of a piece of skin from the perineal area reduced total aerobic plate counts and Escherichia coli counts on carcasses derived from both woolly and shorn groups of lambs. Similar results were found when the "Y-cut" was delayed in the dressing sequence, but E. coli counts increased slightly in one group. The use of a wide-blow shear prior to the opening cut on the hindleg of carcasses derived from woolly lambs resulted in a slight increase in the microbiological contamination on the leg. The removal of a piece of skin from the perineal area reduced scores for faecal contamination despite a small increase in contamination with wool. Changes in visible contamination in response to the two other dressing procedures were principally effected through changes in levels of contamination with wool. Irrespective of dressing procedures, levels of microbiological and visible contamination were lower on carcasses derived from shorn compared with woolly lambs. These studies demonstrated that, although they are reasonable indicators, the use of parameters of visible contamination as a measure of carcass hygiene must be treated with caution. This is especially the case if a genuine HACCP-based system for the control of dressing hygiene for a particular class of slaughtered livestock is to be implemented.     

The bacteriological condition of eviscerated chickens processed under controlled conditions in a spin-chilling system and sampled by two different methods

Quantitative changes have been determined in the flora of chicken carcasses after passage through a series of three separate spin‐chillers. The majority of organisms were eliminated from the chill‐water during processing by using 1.7 1 of water per carcass and 45 to 50 ppm of total residual chlorine in the first two chillers and 1.0 1 of water per carcass and 25 to 30 ppm of residual chlorine in the third chiller.

Total viable counts at 20 and 37 °C and levels of coli‐aerogenes bacteria obtained from the rinsing of whole carcasses were reduced by more than 90% during chilling. Results obtained both with and without the use of chlorination compared favourably with those claimed for other chilling systems. It was concluded that the main effect of chlorination in the chillers was to destroy organisms washed from the carcasses, thus avoiding recontamination.

A comparison of two different sampling methods showed that maceration of neck‐skin usually gave higher counts of both faecal and spoilage bacteria after chilling than the rinsing of whole carcasses.     

Campylobacter control in poultry by current intervention measures ineffective: urgent need for intensified fundamental research

Campylobacter-contaminated poultry meat is an important source of foodborne gastroenteritis and poses a serious health burden in industrialized countries. Broiler chickens are commonly regarded as a natural host for this pathogen and infected birds carry a very high Campylobacter load in their gastrointestinal tract, especially the ceca. This results in contaminated carcasses during processing. While hygienic measures at the farm and control measures during carcass processing can have some effect on the reduction of Campylobacter numbers on the retail product, intervention at the farm level by reducing colonization of the ceca should be taken into account in the overall control policy. This review gives an up-to-date overview of suggested on-farm control measures to reduce the prevalence and colonization of Campylobacter in poultry.     

Campylobacter fetus subsp. jejuni in poultry reared under different management systems in Nigeria

Cloacal swabs from 487 live birds in 36 flocks and 70 poultry carcasses were cultured for Campylobacter fetus subsp. jejuni. It was isolated from 12.3% of the birds in 19 flocks. Chickens, turkeys, and guinea fowl differed from one another in isolation rates of the organism. Management system affected its occurrence, and only 7.1% of eviscerated carcasses yielded it. It was concluded that bird species, management system, and immersing slaughtered poultry in boiling water before dressing affect recovery of C. fetus subsp. jejuni from live birds and carcasses.     

Elimination of Salmonella spp. by lactic acid

The aim of the present study was to determine the elimination of Salmonella by different lactic acid concentrations in microbiological media and on turkey carcass elements. The average bacteria counts in the control samples without lactic acid were: 1.8 x 10(8), 1.1 x 10(8) and 2.3 x 10(8), for S. Enteritidis, S. Anatum and S. Typhimurium, respectively. The concentration of lactic acid of 0.1% in the agar media completely inhibited the growth of all Salmonella strains. At 0.05% lactic acid concentration, the bacteria count was 2 log cycles lower and at a 0.03% solution it was 1 log cycle lower than that in the respective control samples. However, the examined bacteria developed in the presence of 0.02% and 0.01% lactic acid concentrations and their counts fell into the same log brackets. An analysis of the experimental results obtained from turkey carcass elements immersed in the lactic acid solution showed that the Salmonella identification rate was determined by the bacteria inoculum spread over the turkey carcass surface. The contamination of 10(1) CFU of Salmonella spread onto the turkey carcass was completely eliminated by immersing the carcasses in 1% or 2% lactic acid solutions. The contamination of turkey carcass elements with 10(2) CFU of S. Enteritidis and their immersion in 2% lactic acid solution for 15 min resulted in the reduction of the number of samples with Salmonella compared to the number of control samples with Salmonella. At contaminations of 10(3) CFU on the carcass surfaces, the immersions in 1% and 2% lactic acid solutions did not reduce Salmonella counts.