Quantification of campylobacter species cross-contamination during handling of contaminated fresh chicken parts in kitchens

Numerous outbreak investigations and case-control studies for campylobacteriosis have provided evidence that handling Campylobacter-contaminated chicken products is a risk factor for infection and illness. There is currently extremely limited quantitative data on the levels of Campylobacter cross-contamination in the kitchen, hindering risk assessments for the pathogen commodity combination of Campylobacter and chicken meat. An exposure assessment needs to quantify the transfer of the bacteria from chicken to hands and the kitchen environment and from there onto ready-to-eat foods. We simulated some typical situations in kitchens and quantified the Campylobacter transfer from naturally contaminated chicken parts most commonly used in Germany. One scenario simulated the seasoning of five chicken legs and the reuse of the same plate for cooked meat. In another, five chicken breast filets were cut into small slices on a wooden board where, without intermediate cleaning, a cucumber was sliced. We also investigated the transfer of the pathogen from chicken via hands to a bread roll. The numbers of Campylobacter present on the surfaces of the chicken parts, hands, utensils, and ready-to-eat foods were detected by using Preston enrichment and colony counting after surface plating on Karmali agar. The mean transfer rates from legs and filets to hands were 2.9 and 3.8%. The transfer from legs to the plate (0.3%) was significantly smaller (P < 0.01) than the percentage transferred from filets to the cutting board and knife (1.1%). Average transfer rates from hands or kitchen utensils to ready-to-eat foods ranged from 2.9 to 27.5%.     

Campylobacter contamination in French chicken production from farm to consumers. Use of a PCR assay for detection and identification of Campylobacter jejuni and Camp. coli

AIMS: Campylobacter contamination in French chicken production from the farm to the consumer was determined using a PCR assay for bacteria detection and identification. METHODS AND RESULTS: Samples were bird droppings from poultry houses, neck skins, livers, hearts, gizzards, wings, legs and escalopes from slaughterhouses and gizzards, legs, drumstick, breast and escalopes from a supermarket. Bacterial DNA extraction was performed after an enrichment step in a broth and was followed by PCR. An internal control (IC) was used for both DNA extraction and PCR. Campylobacter were detected in 79.2% of poultry houses. Of the 303 samples, 201 were Campylobacter-positive (i.e. 66.3%) including 43.2% faecal samples, 5.6% slaughterhouse samples and 17.5% supermarket samples. There was no significant difference between the molecular method and the conventional culture technique for Campylobacter detection whatever the samples. The sensitivity was 5 UFC g(-1) of samples and 1.5 x 10(3) UFC ml(-1) of enrichment broth. The use of IC revealed PCR inhibition in 13 samples and problems in the DNA extraction in five samples. CONCLUSION: Significant Campylobacter contamination affects all stages of French chicken production. SIGNIFICANCE AND IMPACT OF THE STUDY: The understanding of Campylobacter contamination at different levels of chicken production and the determination of the best place(s) for intervention are important for significantly decreasing Campylobacteriosis. Our technique is rapid and can be used on different chicken samples for Campylobacter detection and identification.     

Incidence of Campylobacter and Salmonella isolated from retail chicken and associated packaging in South Wales

AIMS: To investigate the incidence of Campylobacter and Salmonella contamination associated with supermarket and butchers' shop chicken and related packaging. METHOD AND RESULTS: Three hundred raw samples (whole chicken, chicken breast with skin or chicken pieces) were purchased on a monthly basis for seven months. Packaging associated with the chicken was also sampled to provide isolation data for external and whole packaging. Campylobacter and Salmonella were isolated from 68% and 29% of retail chicken, respectively. Campylobacter was isolated from 3% of external and 34% of whole packaging overall. Salmonella was absent from external packaging but was isolated from 11% of whole packaging. No significant trends in isolation rates of the organisms were obtained during the period of sampling. CONCLUSIONS: The food industry and consumers should be made aware of the potential risk of Campylobacter and Salmonella on both the external and internal surfaces of packaging in addition to chicken itself. SIGNIFICANCE AND IMPACT OF THE STUDY: Chicken and chicken packaging is a potential vehicle for the introduction of pathogens in retail and domestic kitchens and in particular for the cross-contamination of Campylobacter and Salmonella.     

Implications of white striping and wooden breast abnormalities on quality traits of raw and marinated chicken meat

One of the consequences of intense genetic selection for growth of poultry is the recent appearance of abnormalities in chicken breast muscles, such as white striping (characterised by superficial white striations) and wooden breast (characterised by pale and bulged areas with substantial hardness). The aim of this study was to evaluate the quality traits of chicken fillets affected by white striping and wooden breast abnormalities. In two replications, 192 fillets were divided into the following four classes: normal (n=48; absence of any visual defects), white striping (n=48, presence of white striations), wooden breast (n=48; diffusely presence of hardened areas) and white striping/wooden breast (n=48; fillets affected by both abnormalities). Morphology, raw meat texture and technological properties were assessed in both unprocessed (pH, colour, drip loss, cooking loss and cooked meat shear force) and marinated meat (marinade uptake, purge loss, cooking loss and cooked meat shear force). Fillets affected by white striping, wooden breast or both abnormalities exhibited higher breast weights compared with normal fillets (305.5, 298.7, 318.3 and 244.7 g, respectively; P<0.001). Wooden breast, either alone or in combination with white striping, was associated with a significant (P<0.001) increase of fillet thickness in the caudal area and raw meat hardness compared with both normal and the white striping abnormality, for which there was no difference. Overall, the occurrence of the individual and combined white striping and wooden breast abnormalities resulted in substantial reduction in the quality of breast meat, although these abnormalities are associated with distinct characteristics. Wooden breast fillets showed lower marinade uptake and higher cooking losses than white-striped fillets for both unprocessed and marinated meats. On the other hand, white-striped fillets showed a moderate decline in marinade and cooking yield. Fillets affected by both abnormalities had the highest (P<0.001) ultimate pH values. In contrast, the effects on colour of raw and cooked meat, drip loss, purge loss and cooked meat shear force were negligible or relatively low and of little practical importance. Thus, the presence of white striping and wooden breast abnormalities impair not only breast meat appearance but also the quality of both raw and marinated meats mainly by reducing water holding/binding abilities.     

Survival of Campylobacter jejuni in chicken meat at frozen storage temperatures

The aim of this study was to determine the survival of Campylobacter jejuni in chicken meat samples at frozen temperatures and given length of incubation and to determine the impact of aerobic bacteria on the survival of C. jejuni. The chicken meat samples were inoculated with C. jejuni NCTC 11351 suspensions and stored in bags at temperatures of -20°C and -70°C. The mean value of C. jejuni from meat samples decreased from 7.52 log10 CFU/g after 30 minutes of incubation at ambient temperature, to 3.87 log10 CFU/g on the eighth week of incubation at -20°C, and to 3.78 log10 CFU/g at incubation at -70°C after the same incubation period. Both freezing temperatures, -20°C and -70°C, decreased the number of campylobacters. The presence of aerobic mesophilic bacteria did not influence the survival of C. jejuni in chicken meet samples. Keeping poultry meat at freezing temperatures is important for the reduction of C. jejuni, which has a strong influence on the prevention of occurrence of campylobacteriosis in humans.     

Transfer of Campylobacter jejuni from raw to cooked chicken via wood and plastic cutting boards

Aims: We quantified Campylobacter jejuni transferred from naturally contaminated raw chicken fillets and skins to similar cooked chicken parts via standard rubberwood (RW) and polyethylene cutting boards (PE). Methods and Results: RW and PE cutting boards (2·5 × 2·5 cm²) were constructed. RW surfaces were smooth and even, whereas PE was uneven. Scoring with scalpel blades produced crevices on RW and flaked patches on the PE boards. Raw chicken breast fillets or skin pieces (10 g) naturally contaminated with Camp. jejuni were used to contaminate the cutting boards (6·25 cm²). These were then briefly covered with pieces of cooked chicken. Campylobacter jejuni on raw chicken, the boards, and cooked chicken pieces were counted using a combined most‐probable‐number (MPN)‐PCR method. The type of cutting board (RW, PE; unscored and scored) and temperature of cooked chicken fillets and skins were examined. Unscored PE and RW boards were not significantly different in regards to the mean transfer of Camp. jejuni from raw samples to the boards. The mean transfer of Camp. jejuni from scored RW was significantly higher than from scored PE. When the chicken fillets were held at room temperature, the mean transfer of Camp. jejuni from scored RW and PE was found to be 44·9 and 40·3%, respectively. Conclusions: RW and PE cutting boards are potential vehicles for Camp. jejuni to contaminate cooked chicken. Although cooked chicken maintained at high temperatures reduced cross‐contamination via contaminated boards, a risk was still present. Significance and Impact of the Study: Contamination of cooked chicken by Camp. jejuni from raw chicken via a cutting board is influenced by features of the board (material, changes caused by scoring) and chicken (types of chicken parts and temperature of the cooked chicken).     

Antimicrobial resistance of Campylobacter isolates from retail meat in the United States between 2002 and 2007

The emergence of antimicrobial resistance in Campylobacter spp. has been a growing public health concern globally. The objectives of this study were to determine the prevalence, antimicrobial susceptibility, and genetic relatedness of Campylobacter spp. recovered by the National Antimicrobial Resistance Monitoring System (NARMS) retail meat program. Retail meat samples (n = 24,566) from 10 U.S. states collected between 2002 and 2007, consisting of 6,138 chicken breast, 6,109 ground turkey, 6,171 ground beef, and 6,148 pork chop samples, were analyzed. A total of 2,258 Campylobacter jejuni, 925 Campylobacter coli, and 7 Campylobacter lari isolates were identified. Chicken breast samples showed the highest contamination rate (49.9%), followed by ground turkey (1.6%), whereas both pork chops and ground beef had <0.5% contamination. The most common resistance was to doxycycline/tetracycline (46.6%), followed by nalidixic acid (18.5%), ciprofloxacin (17.4%), azithromycin and erythromycin (2.8%), telithromycin (2.4%), clindamycin (2.2%), and gentamicin (<0.1%). In a subset of isolates tested, no resistance to meropenem and florfenicol was seen. C. coli isolates showed higher resistance rates to antimicrobials, with the exception of doxycycline/tetracycline, than those seen for C. jejuni. Pulsed-field gel electrophoresis (PFGE) fingerprinting resulted in 1,226 PFGE profiles among the 2,318 isolates, with many clones being widely dispersed throughout the 6-year sampling period.     

Prevalence of Campylobacter spp., Escherichia coli, and Salmonella serovars in retail chicken, turkey, pork, and beef from the Greater Washington, D.C., area.

A total of 825 samples of retail raw meats (chicken, turkey, pork, and beef) were examined for the presence of Escherichia coli and Salmonella serovars, and 719 of these samples were also tested for Campylobacter spp. The samples were randomly obtained from 59 stores of four supermarket chains during 107 sampling visits in the Greater Washington, D.C., area from June 1999 to July 2000. The majority (70.7%) of chicken samples (n = 184) were contaminated with Campylobacter, and a large percentage of the stores visited (91%) had Campylobacter-contaminated chickens. Approximately 14% of the 172 turkey samples yielded Campylobacter, whereas fewer pork (1.7%) and beef (0.5%) samples were positive for this pathogen. A total of 722 Campylobacter isolates were obtained from 159 meat samples; 53.6% of these isolates were Campylobacter jejuni, 41.3% were Campylobacter coli, and 5.1% were other species. Of the 212 chicken samples, 82 (38.7%) yielded E. coli, while 19.0% of the beef samples, 16.3% of the pork samples, and 11.9% of the turkey samples were positive for E. coli. However, only 25 (3.0%) of the retail meat samples tested were positive for Salmonella. Significant differences in the bacterial contamination rates were observed for the four supermarket chains. This study revealed that retail raw meats are often contaminated with food-borne pathogens; however, there are marked differences in the prevalence of such pathogens in different meats. Raw retail meats are potential vehicles for transmitting food-borne diseases, and our findings stress the need for increased implementation of hazard analysis of critical control point (HACCP) and consumer food safety education efforts.     

Correlation between microbial flora, sensory changes and biogenic amines formation in fresh chicken meat stored aerobically or under modified atmosphere packaging at 4 °C: possible role of biogenic amines as spoilage indicators

This study evaluated the formation of biogenic amines (BAs) in breast chicken meat during storage under aerobic and modified atmospheric packaging (MAP) conditions at 4 °C, the correlation of microbial and sensory changes in chicken meat with formation of BAs and the possible role of BAs as indicators of poultry meat spoilage. Poultry breast fillets were stored aerobically or under MAP (30%, CO₂, 70% N₂) at 4 °C for up to 17 days. Quality evaluation was carried out using microbiological, chemical and sensory analyses. Total viable counts, Pseudomonads and Enterobacteriaceae, were in general higher for chicken samples packaged in air whereas lactic acid bacteria (LAB) and Enterobacteriaceae were among the dominant species for samples under MAP. Levels of putrescine and cadaverine increased linearly with storage time and were higher in aerobically stored chicken samples. Spermine and spermidine levels were also detected in both aerobically and MAP stored chicken meat. Levels of tyramine in both chicken samples stored aerobically and or under MAP were low (< 10 mg kg⁻¹) whereas the formation of histamine was only observed after day 11 of storage when Enterobacteriaceae had reached a population of ca. 10⁷ CFU g⁻¹. Based on sensory and microbiological analyses and also taking into account a biogenic amines index (BAI, sum of putrescine, cadaverine and tyramine), BAI values between 96 and 101 mg kg⁻¹ may be proposed as a quality index of MAP and aerobically-packaged fresh chicken meat. Spermine and spermidine decreased steadily throughout the entire storage period of chicken meat under aerobic and MAP packaging, and thus these two amines cannot be used as indicators of fresh chicken meat quality.     

Survival of Campylobacter jejuni in different gas mixtures

Campylobacter jejuni in fresh chilled chicken meat is known to be a major risk factor for human gastrointestinal disease. In the present study, the survival under chilled conditions of different C. jejuni strains exposed to different gas mixtures usually used for gas packaging of food was examined. Bolton broth and fresh, skinless chicken fillets were inoculated with six and four strains, respectively, and exposed to the gas mixtures 70/30% O(2)/CO(2), 70/30% N(2)/CO(2), and 100% N(2) (the latter only investigated in broth) at refrigeration temperature (4-5 degrees C). In broth culture, the strains survived significantly longer when exposed to 100% N(2) and 70/30% N(2)/CO(2) than in the oxygen-containing gas mixture, 70/30% O(2)/CO(2) (P<0.0001). For the two anaerobic gas mixtures, the reductions only reached 0.3-0.8 log(10) CFU mL(-1) within the same period. In the presence of oxygen, the numbers of C. jejuni were reduced by a minimum of 4.6 log(10) CFU mL(-1) over 21 days. When inoculated onto chicken fillets, the C. jejuni strains also died significantly faster in the oxygen-containing gas mixture, 70/30% O(2)/CO(2) (P<0.0001), reaching reductions of 2.0-2.6 log(10) CFU g(-1) after 8 days. In the gas mixture without oxygen (70/30% N(2)/CO(2)), no reductions were observed.     

Rapid detection of salmonellae in poultry with the magnetic immuno-polymerase chain reaction assay.

Rapid detection of salmonellae in chicken meat was accomplished by using the magnetic immuno-polymerase chain reaction assay (MIPA). A direct polymerase chain reaction assay performed with chicken meat spiked with Salmonella typhimurium resulted in poor sensitivity (approximately 10(7) CFU/g of meat). The use of immunoseparation with a Salmonella serogroup B-specific monoclonal antibody improved the sensitivity, but enrichment was required for the detection of low levels of contamination. Enrichment for 6 h in either buffered peptone water, lactose broth containing tergitol-7, or selenite-cystine broth resulted in the detection of an initial inoculum of 100 CFU per g of meat. Enrichment of the salmonellae present on 25 g of spiked chicken meat for 24 h in either buffered peptone water or selenite-cystine broth before detection by the MIPA yielded a detection limit of approximately 0.1 CFU/g of meat. A detection limit of approximately 1 CFU/g of meat was obtained when the spiked meat was stored at -20 degrees C before enrichment for 24 h and analysis with the MIPA. Although the MIPA was developed for S. typhimurium, a MIPA in which a panel of six monoclonal antibodies specific for Salmonella serogroups A through E was used detected the presence of 0.1 CFU of Salmonella enteritidis per g of chicken meat. These data indicate that the method is applicable to other commonly isolated serotypes.     

Microbiological examination of ready-to-eat cold sliced meats and pâté from catering and retail premises in the UK

AIMS: To establish the microbiological quality of cold ready-to-eat sliced meats and paté from catering and retail premises, and investigate links hypothesized between foodborne Campylobacter infection and the consumption of cold sliced meats. METHODS AND RESULTS: A total of 4078 cold meat and paté samples were collected and examined according to a standardized protocol. Comparison with published microbiological guidelines revealed that most ready-to-eat meat and paté samples (75%) were of satisfactory/acceptable microbiological quality and 25% were of unsatisfactory/unacceptable quality. Two cold meat samples (<1%) were of unacceptable microbiological quality because of the presence of Campylobacter jejuni in 25 g and Listeria monocytogenes at 3.4 x 104 CFU g-1. CONCLUSIONS: Acceptable microbiological quality was associated with premises where the management was trained in food hygiene and those that had hazard analysis in place. Poor microbiological quality was associated with storage above 8 degrees C, presliced meats, infrequent cleaning of slicing equipment and poor control of practices that may lead to cross contamination. SIGNIFICANCE AND IMPACT OF THE STUDY: This study provides important information about the microbiological quality of cold ready-to-eat meats and paté. It also assists caterers, retailers, enforcement officers and policy makers to understand how different food safety practices affect microbiological quality.     

Determination of toxicity of Campylobacter jejuni isolated from humans and from poultry carcasses acquired at various stages of production

AIM: The research focused on the determination of the toxicity variation associated with Campylobacter jejuni isolated from humans and chickens. METHODS AND RESULTS: Campylobacter jejuni isolates were obtained from chicken carcasses and from humans exhibiting symptoms of campylobacteriosis. Using HeLa cells as the in vitro model, toxicity was determined for each isolate. The mean toxicity level of the chicken isolates was significantly lower than that of the human isolates (P < 0.001). There was a wide range of toxicity in C. jejuni isolated from chickens and the percentage of isolates exhibiting low toxicity remaining relatively constant. All C. jejuni isolates from humans possessed either medium or high levels of toxicity. CONCLUSIONS: All wildtype C. jejuni isolates obtained from poultry carcasses may not be equally important as a human foodborne pathogen. SIGNIFICANCE AND IMPACT OF STUDY: Campylobacter jejuni remains a primary foodborne pathogen and increased efforts are needed to determine the impact of wildtype isolates in causing human illness. The present research indicates that all isolates may not be equally important in regards to disease potential. The information found should be included in efforts to develop C. jejuni detection, control and infection modelling.     

The incidence of Campylobacter spp. on processed turkey from processing plants in the midwestern United States

AIM: The primary aim of this study was to determine the incidence of Campylobacter spp. on turkey, presented for processing at participating production plants located in the midwest region of the United States. METHODS AND RESULTS: The two participating plants were visited on a monthly basis for a period of 1 year. Sampling of carcasses was carried out using a surface swab technique. Swabs were obtained from carcasses at two points on the production line - prechill and postchill. In addition, samples of chill water were also obtained for examination. Isolation and detection of Campylobacter was carried out using enrichment in Preston broth with recovery of the organism on blood free Campylobacter selective agar (CCDA). Isolates recovered were screened and identified using the API Campy identification system. The study found that 34.9% of all samples tested were positive for Campylobacter spp. The overall, contamination rates observed for both plants were relatively similar (39.2% for plant A and 30.6% for plant B). Differences were observed in the incidence of Campylobacter spp. on prechill vs postchill carcasses (i.e. 40.8% prechill vs 37.6% postchill for plant A and 41.8% prechill vs 19.8% postchill for plant B). Campylobacter species most often isolated included Camp. jejuni and Camp. coli. Other species recovered were Camp. fetus fetus, Camp. upsaliensis and Camp. lari. CONCLUSIONS: The incidence of Campylobacter spp. on processed poultry was relatively common. Factors such as the processing plant examined, season and the farms presenting birds for processing influenced the incidence of the pathogen. SIGNIFICANCE AND IMPACT OF THE STUDY: Differences were observed in the prevalence of Campylobacter spp. isolated from the two plants examined. The study suggests a seasonal prevalence of Campylobacter in the cooler months with processing conditions also influencing the overall occurrence of the organism. The incidence, isolation and detection of Campylobacter spp. from processed poultry are discussed.     

Specific detection and confirmation of Campylobacter jejuni by DNA hybridization and PCR.

Conventional detection and confirmation methods for Campylobacter jejuni are lengthy and tedious. A rapid hybridization protocol in which a 1,475-bp chromogen-labelled DNA probe (pDT1720) and Campylobacter strains filtered and grown on 0.22-micron-pore-size hydrophobic grid membrane filters (HGMFs) are used was developed. Among the environmental and clinical isolates of C. jejuni, Campylobacter coli, Campylobacter jejuni subsp. doylei, Campylobacter lari, and Arcobacter nitrofigilis and a panel of 310 unrelated bacterial strains tested, only C. jejuni and C. jejuni subsp. doylei isolates hybridized with the probe under stringent conditions. The specificity of the probe was confirmed when the protocol was applied to spiked skim milk and chicken rinse samples. Based on the nucleotide sequence of pDT1720, a pair of oligonucleotide primers was designed for PCR amplification of DNA from Campylobacter spp. and other food pathogens grown overnight in selective Mueller-Hinton broth with cefoperazone and growth supplements. All C. jejuni strains tested, including DNase-producing strains and C. jejuni subsp. doylei, produced a specific 402-bp amplicon, as confirmed by restriction and Southern blot analysis. The detection range of the assay was as low as 3 CFU per PCR to as high as 10(5) CFU per PCR for pure cultures. Overnight enrichment of chicken rinse samples spiked initially with as little as approximately 10 CFU/ml produced amplicons after the PCR. No amplicon was detected with any of the other bacterial strains tested or from the chicken background microflora. Since C. jejuni is responsible for 99% of Campylobacter contamination in poultry, PCR and HGMF hybridization were performed on naturally contaminated chicken rinse samples, and the results were compared with the results of conventional cultural isolation on Preston agar. All samples confirmed to be culture positive for C. jejuni were also identified by DNA hybridization and PCR amplification, thus confirming that these DNA-based technologies are suitable alternatives to time-consuming conventional detection methods. DNA hybridization, besides being sensitive, also has the potential to be used in direct enumeration of C. jejuni organisms in chicken samples.     

Campylobacter in chicken livers and their destruction by pan frying

AIM: To enumerate Campylobacter spp. on the external surface and internal portions of chicken livers, and to assess the cooking required to inactivate naturally present cells. METHODS AND RESULTS: Of 30 livers tested all yielded Campylobacter spp. on their surfaces and 90% were found to contain the organism in internal tissue. Four (13%) livers contained >10(4) MPN campylobacters, and an additional seven (23%) contained >10(3) MPN campylobacters per liver. The internal temperature of pan-fried livers under the conditions used reached a maximum of 70-80 degrees C, and maintaining this temperature for 2-3 min was necessary to inactivate naturally occurring Campylobacter spp. All isolates identified were either C. jejuni or C. coli. CONCLUSIONS: Chicken livers represent a potential source of human campylobacteriosis as they contained >10(4) MPN per liver in 13% of the samples tested. Pan-frying can produce an acceptable product that is safe to eat. SIGNIFICANCE AND IMPACT OF THIS STUDY: The data provided can be used in exposure assessments of Campylobacter in poultry products in terms of both quantitative data and assessing pan-frying and its ability to destroy campylobacters.     

Application of real-time PCR for quantitative detection of Campylobacter jejuni in poultry, milk and environmental water

Campylobacter jejuni is a leading human food-borne pathogen. The rapid and sensitive detection of C. jejuni is necessary for the maintenance of a safe food/water supply. In this article, we present a real-time polymerase chain reaction (PCR) assay for quantitative detection of C. jejuni in naturally contaminated poultry, milk and environmental samples without an enrichment step. The whole assay can be completed in 60 min with a detection limit of approximately 1 CFU. The standard curve correlation coefficient for the threshold cycle versus the copy number of initial C. jejuni cells was 0.988. To test the PCR system, a set of 300 frozen chicken meat samples, 300 milk samples and 300 water samples were screened for the presence of C. jejuni. 30.6% (92/300) of chicken meat samples, 27.3% (82/300) of milk samples, and 13.6% (41/300) of water samples tested positive for C. jejuni. This result indicated that the real-time PCR assay provides a specific, sensitive and rapid method for quantitative detection of C. jejuni. Moreover, it is concluded that retail chicken meat, raw milk and environmental water are commonly contaminated with C. jejuni and could serve as a potential risk for consumers in eastern China, especially if proper hygienic and cooking conditions are not maintained.     

Quantification of Campylobacter Species Cross-Contamination during Handling of Contaminated Fresh Chicken Parts in Kitchens

Numerous outbreak investigations and case-control studies for campylobacteriosis have provided evidence that handling Campylobacter-contaminated chicken products is a risk factor for infection and illness. There is currently extremely limited quantitative data on the levels of Campylobacter cross-contamination in the kitchen, hindering risk assessments for the pathogen commodity combination of Campylobacter and chicken meat. An exposure assessment needs to quantify the transfer of the bacteria from chicken to hands and the kitchen environment and from there onto ready-to-eat foods. We simulated some typical situations in kitchens and quantified the Campylobacter transfer from naturally contaminated chicken parts most commonly used in Germany. One scenario simulated the seasoning of five chicken legs and the reuse of the same plate for cooked meat. In another, five chicken breast filets were cut into small slices on a wooden board where, without intermediate cleaning, a cucumber was sliced. We also investigated the transfer of the pathogen from chicken via hands to a bread roll. The numbers of Campylobacter present on the surfaces of the chicken parts, hands, utensils, and ready-to-eat foods were detected by using Preston enrichment and colony counting after surface plating on Karmali agar. The mean transfer rates from legs and filets to hands were 2.9 and 3.8%. The transfer from legs to the plate (0.3%) was significantly smaller (P < 0.01) than the percentage transferred from filets to the cutting board and knife (1.1%). Average transfer rates from hands or kitchen utensils to ready-to-eat foods ranged from 2.9 to 27.5%.     

Genotyping of Campylobacter spp. from retail meats by pulsed-field gel electrophoresis and ribotyping

AIMS: To determine the genetic relatedness of Campylobacter spp. from retail meat products, and compare the discriminatory power of pulsed-field gel electrophoresis (PFGE) and automatic ribotyping. METHODS AND RESULTS: A total of 378 Campylobacter isolates recovered from 159 raw meats (130 chicken, 25 turkey, three pork and one beef) sampled from 50 retail grocery stores of four supermarket chains in the Maryland suburban area from August 1999 to July 2000 were analysed by PFGE with SmaI, 120 isolates of which were also characterized by ribotyping with PstI using RiboPrinter system. A total of 148 unique PFGE patterns were identified, 91 of which were present in multiple Campylobacter isolates and 24 in multiple meat samples. Nineteen Campylobacter clones with identical PFGE patterns recurred frequently (up to nine times) throughout the sampling period. Comparing ribotyping with PFGE, we identified 44 PFGE patterns and 22 RiboGroups among the 120 isolates tested. Multiple PFGE patterns within one RiboGroup were commonly observed, as well as multiple RiboGroups within one PFGE pattern. CONCLUSIONS: Although Campylobacter present in retail meats were genetically diverse, certain clones persisted in poultry meats. PFGE had a greater discriminatory power than ribotyping, and the two methods were complementary in genotyping Campylobacter. SIGNIFICANCE AND IMPACT OF THE STUDY: Genomic DNA fingerprinting of Campylobacter confirmed diverse and recurrent Campylobacter clones in the retail meats, which provides additional data for a better understanding of the epidemiological aspect of Campylobacter infection.