Escherichia coli and Enterobacteriaceae counts on poultry carcasses along the slaughterline: A systematic review and meta-analysis

BackgroundThe slaughtering process consists of a highly coordinated system of different operations and is of critical importance for meat hygiene. The evaluation of the impact of different stages on bacterial counts is useful to monitor carcass contamination and to improve the hygiene of different stages. Escherichia coli and Enterobacteriaceae are considered an interesting target for microbiological analysis.ObjectivesThe aim of this review was to summarize literature data about the influence of slaughter stage on E. coli and Enterobacteriaceae counts along the poultry slaughterline.ResultsSystematic review of the available literature and the meta-analysis of the data collected revealed that scalding resulted in a significant reduction of E. coli counts. Washing and chilling were able to decrease E. coli counts in a statistically significant way; however, the observed reductions were of no practical importance. Enterobacteriaceae were reduced only by defeathering and washing but no practical significance was observed. None of the other stages of the slaughterline resulted in significant changes of indicator bacteria counts.Conclusions and implicationsInformation provided would be useful to suggest suitable ways for the implementation of processes hygiene in poultry slaughterhouses in particular GMP (Good Manufacturing Practices) and HACCP through the identification of suitable CCPs.     

Potential of Escherichia coli as a surrogate indicator for postchill broiler carcasses with high Campylobacter counts

Surrogating Campylobacter contamination level in broiler carcasses with other bacterial indicators, used to evaluate the hygienic status of the slaughterline operations, might be stimulation to the broiler meat industry to improve control of Campylobacter during slaughter. Theoretically, Escherichia coli might have some practical merits as a potential indicator for carcasses contaminated with Campylobacter. This study investigates the correlation between the counts of E. coli and Campylobacter in 231 postchill broiler carcasses. The impact of setting a process hygiene target based on E. coli counts on reducing the frequency of carcasses contaminated with Campylobacter at level of ≥3 log₁₀ CFU/g was also investigated. Almost half (48.9% (46/94)) of the carcasses with enumerable Campylobacter (≥1 log₁₀ CFU/g) had E. coli counts between 3 and 4 log₁₀ CFU/g. In addition, 54.8% (17/31) of the carcasses contaminated with Campylobacter of ≥3 log₁₀ CFU/g were correlated with E. coli count range of ≥3 & <4 log₁₀ CFU/g. A theoretical scenario assuming that hygiene and processing measures could allow achieving a target for E. coli that not exceeding 3 log₁₀ CFU/g showed a parallel impact on Campylobacter contamination in broiler carcasses. In such scenario, the overall number of Campylobacter-positive carcasses could be dropped from 40.6% to 12.5%; in addition, 80.6% (25/31) of the carcasses contaminated with Campylobacter of ≥3 log₁₀ CFU/g could be eliminated. Findings from this study reveal that a hygiene target based on E. coli count could be used as an indirect sanitary tool for reducing the level of Campylobacter contamination in postchill broiler carcasses.     

Modeling the transmission of livestock associated methicillin-resistant Staphylococcus aureus along the pig slaughter line

The study introduces a new approach for a qualitative transmission assessment of MRSA throughout the pig slaughter process. Based on prevalence data found in literature the MRSA contamination and elimination rates of each individual slaughter step were estimated. The rates were used to set up a Monte Carlo simulation for modeling the propagation of MRSA along the process chain and to quantify the impact of a variable initial prevalence on the outcome prevalence of the carcasses. Sensitivity analyses for the model as well as three different scenarios were performed to estimate the impact of cross contamination during slaughter and to determine the process stages where hygiene interventions are most effective.Regardless of the initial extent of MRSA contamination low outcome prevalences ranging between 0.15 and 1.15% were achieved among pig carcasses indicating that the pig slaughter chain generally includes process steps with the capacity to limit carcass contamination. Especially scalding and singeing can lead to a significant reduction of superficial MRSA contamination during the first half of the slaughter process. Nevertheless, scenario analyses showed that the low MRSA outcome prevalence can only be guaranteed if recontamination during the ongoing slaughter process is obviated. In order to ensure a low MRSA load on pig carcasses at the end of slaughter the abattoir should primarily concentrate on controlling the process parameters of scalding and singeing and avoiding recontamination at subsequent process steps.     

Industry-level changes in microbial contamination on market hog and broiler chicken carcasses between two locations in the slaughter process

Pork and poultry products have been implicated in a substantial proportion of microbial foodborne illnesses such as salmonellosis and campylobacteriosis. Understanding the similarities and differences between the effectiveness of interventions applied during slaughter to the two commodities can help identify opportunities to reduce the risk of foodborne illness. This study uses data from two national surveys and censored data techniques to assess the concentrations of microbial contamination on broiler chickens and market hogs at two points in the slaughter process. Statistical distributions are fitted to estimate the average concentrations of microbial contamination, the variability in these concentrations, and the average reduction in contamination between the two locations for pork and chicken produced in the United States. The concentrations of Salmonella and generic Escherichia coli (GEC) are estimated for hog carcasses; the concentrations of Salmonella, GEC, and Campylobacter are estimated for chicken carcasses. These datasets are also used to study the magnitude of seasonal changes in concentrations of microbial contamination and to demonstrate the potential utility of using the reduction in the average aerobic plate count between the pre-evisceration and post-chill stages of the slaughter process as an indicator of the corresponding reduction in other species of bacteria. The study finds interventions for hog carcasses achieve much larger reductions in contamination than those applied to chicken. However, the variability in the concentration of Salmonella contamination on pork is significantly higher, suggesting an opportunity to decrease risk by ensuring more consistent reductions across the industry. The study also finds, for both commodities, that the log₁₀ reductions in the concentrations of GEC are similar to the log₁₀ reductions in Salmonella, while the log reduction in Campylobacter on chicken was substantially greater than for both GEC and Salmonella. Additional analyses demonstrate modest seasonal increases in contamination only on hog carcasses as well as demonstrating that reductions in APC are indicative of reductions in all other organisms, suggesting its potential as an effective indicator organism.     

A risk-based approach for evaluation of hygiene performance at pig slaughter

In Denmark, the pig slaughterhouses have a daily input of pigs infected and/or contaminated with Salmonella, and the slaughter hygiene has major influence on the level of Salmonella contamination on the meat leaving the slaughterhouse. However, the relationship between the effect of improved hygiene performance and the consequential reduction of human health risk has not been estimated so far. In this study, swab samples from 2702 pig carcasses were collected, originally for other purposes, from five large Danish slaughterhouses in a period from 2005 to 2007, covering all seasons of the year. The samples were analysed quantitatively for E. coli and semi-quantitatively for Salmonella. A positive association between the number of E. coli on carcasses and the prevalence of Salmonella positive carcasses was shown. For carcasses positive for Salmonella, a positive association was also shown between the number of E. coli and the number of Salmonella on the carcass. As no biological association has been reported between faecal shedding of E. coli and presence of Salmonella, the relationship was considered to be associated with the level of faecal contamination. The positive association between E. coli and Salmonella was used as basis for developing a quantitative risk assessment model for Salmonella, using the level E. coli as model input. The model output associated the hygiene performance with a relative risk estimate of human salmonellosis. The overall objective was to develop a decision support tool that can be used to support risk-based hygiene interventions in pig slaughterhouses.     

Effect of extending processing plant operating time on the microbiological quality and safety of broiler carcasses

In Australia, increased consumer demand for chicken meat and socioeconomic pressures have forced poultry operations to extend plant operating time with delayed spin-chiller emptying and cleaning to maximise water use efficiency. There are concerns that these measures may compromise the microbiological quality and safety of the product. Therefore, the objective of this trial was to determine the microbiological status of broiler carcasses collected hourly during 24 h and 48 h continuous chiller operation within a three week period (total n = 196). Carcass rinses were analysed for total viable count, Escherichia coli and Campylobacter spp. counts, and Salmonella prevalence. Corresponding spin-chiller parameters (pH, oxidation-reduction potential [ORP], core temperature and HOCl concentration) were recorded. There was no statistically significant difference (P > 0.05) in bacterial populations and spin-chiller parameters when various sized chickens were processed. Therefore, the microbiological data and consequent quality were shown to be statistically equivalent between carcasses sampled from 24 h to 48 h continuous processing using a fully automated (water temperature, pH and chlorine control) spin-chiller. However, improvements to processing, including rehang and scald hygiene, and weight-specific hypochlorous acid concentrations, should be researched in order to further reduce bacterial contamination.     

Prevalence,strain identification and antimicrobial resistance of Campylobacter spp. isolated from slaughtered pig carcasses in Brazil

The aim of this study was to investigate the rate of contamination, species identification and antimicrobial resistance of thermophilic Campylobacter spp. in pig carcasses during the slaughter process in a slaughterhouse in Brazil. Two hundred and fifty-nine samples were collected at 7 different stages of the slaughter process for Campylobacter determination by both qualitative and quantitative methods. Typical colonies were subjected to API Campy, real-time polymerase chain reaction (PCR) and antimicrobial resistance testing. Campylobacter was found in 18.9% of the carcasses and 3.5% of the samples. Dehairing was the slaughter stage with the highest Campylobacter contamination (55.6%). All Campylobacter strains were confirmed by real-time PCR and showed multi-drug resistance to cephalothin, nalidixic acid, norfloxacin, tetracycline and trimethoprim. None of the strains were resistant to amoxicillin/clavulanic acid, ampicillin and chloramphenicol. Despite the low occurrence of Campylobacter spp. in pig samples, the antimicrobial resistance of Campylobacter strains represents a considerable risk for the consumption of pork meat and confirms the need for continuous monitoring of Campylobacter in the pig production chain.     

Ratio between carcass-and skin-microflora as an abattoir process hygiene indicator

In two abattoirs, each slaughtering both cattle and pigs, 100 cattle and 100 pigs were randomly selected and sampled. From each animal, two samples were taken: a) immediately after sticking of bovines or stunning of pigs, approximately 2000 cm² hide (cattle) or 1500 cm² skin (pigs) areas were sponge-swabbed; and b) at the end of slaughter line but before chilling, the same areas on corresponding dressed carcasses were sponge-swabbed. In each swab-sample (400 in total), total viable count (TVC) and Enterobacteriaceae count (EC), as well as Escherichia coli O157 (in cattle) or Salmonella (in pigs) occurrence, were determined and used to assess process hygiene in the abattoirs. The results indicated that simply fitting mean TVC and/or EC on final carcasses into an acceptable, marginal or unacceptable process hygiene category (according to current microbiological EU process hygiene criteria) did not enable characterisation of each process with respect to its ability to reduce the transfer of incoming microbial loads (i.e. on skins) onto dressed carcasses. On the other hand, determining the ratio between mean TVC and/or EC on final carcasses and those on corresponding skins enabled more precise assessment of the hygiene of each abattoir process, as well as more reliable differentiation between abattoirs. On the other hand, occurrence of E. coli O157 in cattle or Salmonella in pigs (skins and/or carcasses), being dependant on varying factors including those on-farm/pre-abattoir, did not appear to be very useful for characterisation of the process hygiene but is valuable for the purposes of consumer exposure assessment and pathogen reduction.     

Antibacterial activity of decontamination treatments for pig carcasses

Prevention or reduction of carcass contamination with food-borne pathogens during slaughter is of particular importance. Antimicrobial intervention technologies are therefore gaining increasing interest in the slaughter process. In this review, we screened the available recent literature on the decontamination of pig carcasses and appraised the antibacterial activity of treatments. Compared to poultry and beef carcasses, data on decontamination treatments for pig carcasses are so far limited and mainly physical and chemical interventions were investigated. Physical treatments were on the one hand part of the normal pig slaughter process. Dependent on time and temperature conditions, the bactericidal effect of scalding was shown in several studies, whereas the effect of singeing or chilling differed widely. On the other hand, interventions as hot water spraying, steam treatment or ultraviolet light were additionally applied with the specific objective of carcass decontamination. Hot water spraying and steam treatment thereby yielded bacterial reductions ranging from 1.0 to 2.1 orders of magnitude. Chemical interventions primary included lactic and acetic acid. Under commercial conditions, lactic acid treatment yielded bacterial reductions ranging from 0.2 to 1.0 orders of magnitude.     

A molecular survey of farmed and edible snails for the presence of human enteric viruses: Tracking of the possible environmental sources of microbial mollusc contamination

Snails have been grown or harvested for human consumption for centuries. Similarly to tissues or meat of other food animals, snail meat should be free from microbiological hazards including viruses. The aim of the study was to investigate the presence of human enteric viruses (hepatitis A and E virus, norovirus genogroup I, II and human adenovirus) in farmed and free-living snails intended for human consumption. In order to find the possible sources of snail contamination with viruses, the quality management system operating in the most widely-adopted snail farming system in Poland was reviewed. Additionally, the process hygiene criteria were checked through testing of snail meat and soil samples for bacterial contamination. Snails of genus Cornu and Helix were collected from two heliciculture farms and a purchase point. They were subjected to bacteriological (n = 180) and viral examination (n = 60). In the case of soil samples (n = 8) they were taken from different areas along the breeding cycle of the snails. For virus detection several real-time PCR protocols with an incorporated target-specific internal amplification control (IAC) were used. Determinations of the total aerobic bacteria count (TBC), number of Enterobacteriaceae (ENC) and enterococci (ECC) were performed using the international reference methods. Human enteric viruses were not detected in any of the tested snail samples. TBC for raw snail meat ranged from 5.1 up to 6.6 log cfu/g and ENC values did not exceed 4.8 log cfu/g. The ECC counts were below 2.0 log cfu/g. The overall microbiological status of snail meat indicated good hygiene and appropriate environmental conditions being maintained during snail breeding. TBC for soil samples was in the range of 6.0–7.7 log cfu/g indicating a low or moderate level of contamination. Only the soil samples from the plots used at the fattening stage were characterised by high ECC content increasing the risk of virus occurrence. In contrary to the sporadic finding of ECC, the ubiquitous presence of bacteria from the Enterobacteriaceae family in all types of soil samples was shown. A good microbial quality of snail meat resulted from the implemented GMP/GHP programmes and food safety management practices. This strategy appeared sufficient in reduction of microbiological risk and in prevention of virus contamination in snails. The study showed that the risk of foodborne virus infection due to consumption of snails and related products is considered negligible.     

Determination of microbiological contamination sources during frozen snail meat processing stages

This study has been conducted to determine the major contamination sources during frozen snail meat processing. Seventeen different control points and/or sample types (live snail, and snail meats after steaming, after shell removal, after first boiling, after gutting, after second boiling, after packaging and as frozen snail meat; air samples from gutting room, boiling room and packaging room; samples from gutting counter tops, package surfaces, scissors used during processing, forks used during processing, personnel hands, and potable water) have been examined for the enumeration of total aerobic mesophilic bacteria, coliforms, Escherichia coli, Enterobacteriaceae, coagulase positive staphylococci, Salmonella spp., Listeria spp., and yeast and molds. From the control points examined, raw material and environmental air were found as the primary contamination sources. Personnel hands and equipment used were determined as the secondary contamination sources. Second boiling and freezing stages during processing were determined to reduce the overall contamination rate, and therefore had positive effects on the microbiological quality of the final product. Programs approving the acceptance of snails only with low initial microbial counts to the plant, giving emphasis to processing in proper hygiene conditions with sufficient sanitary applications is strongly recommended.     

Antibacterial activity of decontamination treatments for cattle hides and beef carcasses

There is increasing interest in effective decontamination treatments because healthy food-producing animals can harbor food-borne pathogens and complete prevention of contamination during slaughter can hardly be warranted. Thus we reviewed the available literature and appraised the antibacterial activity of physical, chemical and biological interventions applied on cattle hides and beef carcasses. Based on the evaluated studies, the efficacy of water sprayings, organic acids and their combinations was most frequently investigated for the decontamination of cattle hides and beef carcasses. Most data originated from laboratory-based studies using inoculated samples and extrapolation of these results to commercial practices is restricted. Application of interventions at slaughter plants reduced the bacterial loads on hides and carcasses to some extent, but reductions were clearly lower than those obtained under laboratory conditions. Thus hot water, steam, acetic acid or lactic acid treatment mainly yielded bacterial reductions below two orders of magnitude on carcasses. Under commercial conditions, the use of multiple sequential interventions at different points during slaughter must also be considered in order to enhance the microbiological safety of carcasses. On the other hand, decontamination treatments always must be considered part of an integral food safety system.     

Microbiological quality of hygienically processed buffalo carcasses

Studies were conducted to assess the microbiological quality of buffalo carcasses processed hygienically in a modern abattoir as against those processed in traditional slaughter units of different sites. The hygienic measures followed include abattoir clean up operation, processing on overhead rail, careful removal of skin and viscera, closure of oesophagus and rectum and washing the carcasses with a spray of clean water. The carcasses, meat cuts and minced meat obtained from both the sources were examined for microbial load. A significant (P⩽0.001) difference in microbial load was seen in carcasses obtained from two sources, with carcass from traditional slaughter units showing 1.0–2.50 log higher microbial load. The reduction in microbial load in carcasses processed in a modern abattoir was attributed to the hygienic measures followed. The microbial load was high in shoulder portion and lower in leg portion and the data indicated that samples of shoulder, neck and rib surfaces provide a more realistic estimate of microbial load on buffalo carcasses. The meat cuts obtained from hygienically processed carcass had a shelf-life of six days as against three days for those obtained from traditional slaughter unit. The minced meat from hygienically prepared carcass had a shelf-life of four days as against one day for those obtained from local slaughter unit. The study indicated that by adopting proper hygienic and sanitary practices during processing of buffalo meat would yield meat with acceptable microbiological quality with extended shelf-life.     

A risk assessment of salmonellosis linked to chicken meals prepared in households of China

A quantitative microbiological risk assessment model was used to quantify the risk of salmonellosis caused by bacterial growth and cross-contamination of chicken meals prepared in households of China. Chinese data on initial loads of Salmonella in chicken carcasses sold at retail, storage time and handling of raw chicken meat in household kitchens and confirmatory transfer rates of Salmonella among different kitchen objects were collected. Only one third of Chinese families in our sample separated the cutting board between raw and ready-to-eat foods. The cross-contamination of ready-to-eat foods from chicken meals via the cutting board, the knife and cooks’ hands increased the frequency of pathogen ingestion and the risk of salmonellosis. A significant decrease in the risk of salmonellosis could be achieved by reducing the cross-contamination when handling raw chicken meat and ready-to-eat foods. Decreasing the prevalence of Salmonella contamination to 8.8% or removing chicken carcasses with contamination densities higher than 100 MPN/100 g at retail was less effective. Using transfer rates of Salmonella from raw chicken meat to the wooden cutting board instead of that from references, a statistically higher risk of salmonellosis per serve due to the cross-contamination in households was observed. The present study validated values of hygiene practices in China to reduce the risk of salmonellosis from contaminated raw chicken meat at retail. Deliberate surveys for cooking behaviors and transfer rates of Salmonella from and to different objects including wooden cutting boards were needed.     

Food Safety Management System validation and verification in meat industry: Carcass sampling methods for microbiological hygiene criteria – A review

During validation and verification of the system for the proper implementation of HACCP principles, it is essential to rely on microbiological data. Considerable science research has been carried out during the last twenty years on sampling and testing of carcasses for hygiene criteria. This includes the preferable indicator microorganisms to be used, in order to indicate the general hygiene of slaughtering procedures, the evaluation of microbiological data gathered and the sampling methods. Furthermore, European Union (EU) and the United States have adopted the procedures for HACCP validation and verification in their legislation. The aim of this review is to demonstrate the relevant modern trends in this field of food science. In conclusion, microbiological data based on the indicators should be interpreted only to assess general trends in the hygiene process of the operator in order to take corrective action. Microbiological results, obtained only at the end of the slaughtering process, do not provide information on the cause of the problem. Therefore, ‘process-based’ microbiological criteria which are based on values measured at various stages of the process, including final carcass values, should be used. Finally, in order to implement an adequate monitoring system, non-destructive techniques of carcass sampling could be used instead of excision. The microbial recovery may be lower, but it is proportional to the excision recovery and therefore, non-destructive techniques, like swabbing with sponges, could be a practical sampling method for the estimation of indicators during the slaughtering procedure and hygiene evaluation.     

Variation in the effect of carcass decontamination impacts the risk for consumers

To enhance food safety, whole carcass decontamination during slaughter has been considered as a control measure to reduce pathogen concentrations on meat. The effect of such decontamination is usually measured in terms of the mean log reduction in concentration. However, the variation in this reduction may also contribute to the overall impact of the decontamination measure. Therefore, this study focuses on the relative contribution of mean and variation for the effect of decontamination in the slaughter-line expressed in terms of the effect on human health risk.A stochastic risk model is developed to assess the potential effects of pig carcass decontamination at the end of slaughter on the risk of salmonellosis for Danish consumers. Salmonella concentrations are represented by a lognormal distribution fitted to microbiological data, characteristic for Salmonella numbers on carcasses at the end-point of Danish slaughterhouses. Decontamination scenarios are represented by various gamma distributions with different means and standard deviations. The values chosen for these parameters are based on experimental data of the effect of real decontamination procedures applied to pork.Results show that the variation of decontamination has a relevant effect on risk reduction for the consumer: the higher the variation, the lower the overall risk reduction. This effect is particularly evident for procedures with a lower mean reduction (≤2.5 log₁₀), but less so for highly efficient decontamination procedures (>2.5 log₁₀ mean reduction). This difference is affected by the initial level of carcass contamination with Salmonella. With increasing mean and standard deviation of initial bacterial concentrations, it becomes increasingly relevant to account for the variation of the decontamination action, even if the mean decontamination effect is high.We conclude that for decontamination procedures with an overall mean reduction effect of 1–2 log₁₀, it is important to consider the variation in effect: if the variation is large, the final effect of decontamination can be considerably smaller than expected on the basis of the mean only and efforts should be put in place to reduce the variation of the procedure. However, when a treatment of high mean reduction (>2.5 log₁₀) is used, the impact of variation becomes smaller and may be negligible.     

Reducing microbial counts on chicken and turkey carcasses using lactic acid

A 4% concentration of lactic acid, buffered to pH = 3.7, was applied by spraying directly after the inside-outside washer of a commercial chicken and a turkey production line with the aim of reducing microbial counts on the carcasses. Slight paling of the skin and slight greying of the leaf fat was observed on the carcasses but this was considered to be commercially acceptable. Microbial reductions varied with length of storage after killing, and after treatment with acid. For both chicken and turkey, there was a highly significant difference (p < 0.001) in aerobic plate counts between control and treated carcasses up to Day 9, but no difference on Days 13 and 16. The largest difference between the aerobic plate counts on control and treated carcasses was 2.1 log₁₀ cfu/g on chicken (Day 6) and 1.1 log₁₀ cfu/g on turkey (Day 9). The prevalence of Campylobacter on turkey carcasses on the day after slaughter was reduced significantly (p < 0.001) by the application of the acid. The results indicate that the application of lactic acid offers a method of reducing microbial counts on poultry and may have implications for shelf life and food safety.     

Hygienic level and surface contamination in fresh-cut vegetable production plants

The number of vegetable processing plants has increased during recent years in many countries. At the same time, fresh vegetable products have been implicated by epidemiologic investigations as sources of infection. Fresh vegetables are susceptible to microbial contamination after harvest due to their high water and nutrient contents. Contamination may occur at all stages during production. The aim of this study was to determine the level of surface contamination after cleaning in several fresh-cut vegetable processing plants, and to identify the critical points in the processes and operating rooms. Surface and environmental samples were taken from the plants after cleaning of the processing devices and surfaces. The levels of surface and air hygiene in the vegetable processing factories were determined with different rapid hygiene monitoring methods. The amounts of total aerobic bacteria, Enterobacteriaceae and β-glucuronidase-positive bacteria, yeasts and moulds on surfaces were measured using Hygicult^® contact plates. ATP bioluminescence was measured luminometrically with an HY-LiTE^®2 equipment. The number of microbes in air was measured with an MAS-100 sampler. The highest levels of total aerobic bacteria, yeasts, Enterobacteriaceae and β-glucuronidase-positive bacteria were detected on machines (cutters, peeling machines etc.). High mean values of ATP were detected e.g. on packaging surfaces (due to high values of wooden boxes) and on cutters. Most of the bacterial counts measured on the surfaces were unacceptable when using the Finnish surface hygiene guidelines as criteria. However, the results should be examined in the context of the type of production and the stage of operation also must be taken into account. Different hygiene areas (FDA, 2008) should be separate enough to allow maintenance of good hygiene in cleaner areas while accepting lower hygiene levels e.g. in primary (early) washing steps. Despite this, the results show that there is a clear need to improve cleaning and hygiene practices in vegetable production. Several practical recommendations were given e.g. concerning cleaning, design of production areas, training of employees and self monitoring of surface hygiene. The information obtained will be used for improvement of practices in the cleaning of vegetable processing factories.     

Integrating statistical process control to monitor and improve carcasses quality in a poultry slaughterhouse implementing a HACCP system

In meat slaughterhouses, the enumeration of certain microorganisms as microbiological quality indicators is very important for verifying effectiveness of the Good Hygiene Practices (GHP) and Hazard Analysis Critical Control Points (HACCP) systems. Microbiological testing of final products as part of the HACCP verifying process may provide information that a process is in control. The aim of this work was to exploit the data from a poultry slaughterhouse implementing HACCP and demonstrate an alternative approach to the conventional statistical analysis using the principles of the Six Sigma quality. The data collected on Total Viable, Total Coliforms and Staphylococcus aureus counts were used to construct control charts (X bar–R control chart) and perform process capability analysis. Based on X bar–R control charts, the process was in a statistical control state but this before its automation was not capable since process capability and process performance indices were below 1.00, indicating the production of poultry carcasses with poor microbiological quality. After process automation, the indices were much higher than 2.00, indicating that the process was capable of producing poultry carcasses within the specification limits.     

Prevalence of Listeria spp. at a poultry processing plant in Brazil and a phage test for rapid confirmation of suspect colonies

Sites and occurrence of Listeria contamination in an industrial poultry processing plant were investigated by sampling carcasses at varying stages of processing and testing the hands and gloves of food handlers as well as the chilling water used in the process. In the course of nine visits to a local processing plant we collected a total of 121 samples: 66 from carcasses, 37 from workers' hands and gloves and 18 from the water used for chilling. Except for the water samples Listeria was isolated at all sampling sites. The species most often isolated was Listeria innocua, which accounted for 28 of the 31 (90.3%) isolates. The frequency of Listeria in the chicken carcasses was similar at bleeding, defeathering and end of evisceration stages (33.3%), reduced during scalding (16.7%), and rose immediately after initial evisceration stage (50%) to peak after packaging (76.2%). The carcasses were contaminated by L. monocytogenes serotypes 1b and 1c only during packaging. The prevalence of Listeria spp. on workers' hands and gloves was 46% mostly with L. innocua (40.5%) followed by L. monocytogenes 1b (11.8%). Chilling water presented more than 100 ppm of chlorine, which could explain why the samples were negative to Listeria. As the contamination by Listeria in the carcasses progressively rose both in number, species and strains during processing it seems reasonable to conclude that those carcasses become contaminated at the processing level. Improvement and innovation measures to control bacteria in general at the processing plant level are necessary to effectively reduce final product contamination by L. monocytogenes. In the course of this work we introduced a bacteriophage susceptibility test to confirm suspected Listeria colonies which was able to reduce the time of analysis to a minimum of 30 h depending on the isolation technique employed.