Quantitative estimation of Campylobacter cross-contamination in carcasses and chicken products at an abattoir

Changes in the Phenotypes of Salmonella spp. in Japanese Broiler Flocks

Salmonella infections represent a leading cause of foodborne illnesses; resistance to third-generation cephalosporins (TGCs), which are a first-choice antimicrobial for treating human Salmonella enteritis, has become a serious public health concern worldwide. Because the consumption of undercooked chicken meat products is a major cause of foodborne salmonellosis in Japan, we conducted three surveys at different periods between 2017 and 2022, with the cooperation of four abattoirs (two in Eastern and two in Western Japan). The first survey was conducted at abattoir A, which is located in Eastern Japan. Salmonella was detected in 84.4% of broiler flocks tested (27/32); among them, all the TGC-resistant isolates obtained from one farm (farm FA) were identified as S. Infantis. Salmonella was recovered from 62.5% of breast meat samples (20/32), with one case suggesting cross-contamination. The second survey was conducted at three other abattoirs to examine the prevalence of TGC-resistant Salmonella, in both Western (abattoirs B and C) and Eastern (abattoir D) Japan. Salmonella was detected in 90.6% of broiler flocks examined (29/32). TGC-resistant S. Infantis was isolated from 2 flocks until 2018 and not thereafter. Subsequently, isolates were identified as TGC-susceptible S. Schwarzengrund in both regions. The third survey was performed at abattoir A to elucidate whether there were changes in the phenotypes. Of the 11 broiler flocks introduced from farm FA, 10 were positive for Salmonella (90.9%); all the isolates were S. Schwarzengrund susceptible to TGC. This study shows that TGC-susceptible S. Schwarzengrund has replaced the resistant phenotypes among broiler flocks in both Eastern and Western Japan. Although chicken meat products could be cross-contaminated with Salmonella during the slaughtering process, reducing the prevalence of Salmonella in broiler flocks remains important to decrease Salmonella enteritis in humans.

[Quantitative Survey of Campylobacter on Chicken Livers in Japan]

Chicken liver is a potential source of campylobacteriosis in humans. Therefore, we determined the number of Campylobacter in chicken liver. In total, 33 vacuum-packed liver products were obtained from retail stores, and found that 27 of the 33 products (81.8%) were contaminated with Campylobacter. Moreover, Campylobacter was isolated from 138 of 149 livers (92.6%) collected from the 27 Campylobacter-positive products. The mean Campylobacter count was 2.3 log10 CFU/g, while Campylobacter count in 22 of the 138 contaminated livers (15.9%) was >3.0 log10 CFU/g. Furthermore, gastrointestinal tract, liver, and bile samples were collected from 35 broilers at chicken processing plants. We isolated Campylobacter from the gastrointestinal tract of 27 broilers (77.1%). Of these 27 broilers, liver of 24 broilers (88.9%) was Campylobacter-positive, with a mean Campylobacter count of 2.8 log10 CFU/g. Of these 24 broilers, bile of 13 broilers (54.2%) was contaminated with Campylobacter (mean Campylobacter count, 3.5 log10 CFU/mL). Among them, bile of 2 broilers had a Campylobacter count of >8.3 log10 CFU/mL. Collectively, these results indicate that livers derived from broilers colonized with Campylobacter are contaminated with Campylobacter at the time of evisceration. Therefore, to prevent foodborne campylobacteriosis in humans, chicken livers should be thoroughly heated before consumption.

Campylobacter spp. prevalence and fluoroquinolone resistance in chicken layer farms

Chicken is a major source of human campylobacteriosis. Chicken meat originates not only from broilers but also from spent layers; however, few reports have documented the prevalence and antimicrobial resistance of Campylobacter spp. in layers in Japan. Therefore, we investigated the prevalence and antimicrobial susceptibility of Campylobacter spp. in 47 layer farms in Japan. Fecal samples were collected from the youngest and oldest flocks on the farm, and Campylobacter spp. was isolated from 46/47 (97.9%) farms. Among the C. jejuni isolates, the resistance rates to ampicillin, tetracycline, and ciprofloxacin were 29.6%, 22.2%, and 19.8%, respectively. The ciprofloxacin resistance rate (7.3%) in C. jejuni isolated from old flocks was significantly (P<0.01) lower than that in young flocks (32.5%).

Systematic-review and meta-analysis on effect of decontamination interventions on prevalence and concentration of Campylobacter spp. during primary processing of broiler chickens

Scientific advances in pathogen decontamination offer great potential to reduce Campylobacter spp. during primary processing. The aim of this study was to collate data from eligible studies using systematic review, meta-analysis followed by meta-regression. Random effect meta-analysis revealed heterogenous (τ² = 0.6, I² = 98 %) pooled reduction in Campylobacter concentration of 0.6 log₁₀ CFU/carcass and a decrease in relative risk of Campylobacter spp. prevalence in broiler carcasses by 57.2 %. Decontamination interventions during Inside-Outside-Carcass-Wash were most effective on concentration (0.8 log₁₀ CFU/carcass) while those during evisceration were most effective on prevalence (78.0 % decrease in relative risk). Physical decontamination was more effective on Campylobacter prevalence (68.7 % decrease in relative risk) compared chemical treatment (30.3 %). Application through immersion was superior on Campylobacter concentration (0.9 log₁₀ CFU/carcass odds reduction) to spraying (0.5 log₁₀ CFU/carcass odds reduction). Publication bias and small study effect were observed in trials on Campylobacter prevalence but not for concentration. The meta-regression revealed four and seven potential modifier variables for concentration and prevalence respectively. This meta-analysis provides an overview of the expected magnitude in Campylobacter spp. concentration and prevalence with application of decontamination interventions on broiler carcasses along the slaughter process and forms a basis of quantitative microbial risk assessment and derivation of intervention measures. Even though modest microbial concentration reduction is reported there was a large decrease in contamination prevalence during processing interventions.

Highly Prevalent Multidrug-Resistant Campylobacter spp. Isolated From a Yellow-Feathered Broiler Slaughterhouse in South China

The purpose of this study was to investigate the prevalence, antimicrobial resistance, virulence genes, and genetic diversity of Campylobacter spp. along the yellow-feathered broiler slaughtering line in Southern China from December 2018 to June 2019. A total of 157 Campylobacter spp. isolates were identified from 1,102 samples (including 53.6% (75/140) of live chicken anal swab samples, 27.5% (44/160) of defeathering samples, 18.1% (29/160) of evisceration samples, 2.1% (3/140) of washing samples, 1.4% (2/140) of chilling samples, and 1.1% (4/362) of environmental samples). The prevalence of Campylobacter spp. was 14.2%, including 43.9% Campylobacter jejuni, 53.5% Campylobacter coli, and 2.5% other Campylobacter species. The highest antimicrobial resistance rate was found to be against sulfamethoxazole (138/157, 87.9%), and 90.4% (142/157) of the isolates were multidrug resistant (MDR). Examination of resistance-related genes revealed the double base mutated Thr-86-Ile, which informed ACA-TTA, with an Arg-79-Lys substitution in gyrA. Eleven virulence-associated genes (cadF, cdtA, cdtB, ciaB, flaA, imaA, dnaJ, plaA, virB11, racR, and cdtC) were also detected by a polymerase chain reaction (PCR) analysis, and cadF (81.5%) was the most prevalent. Based on an analysis of pulsed-field gel electrophoresis (PFGE) results, we found that Campylobacter spp. could be cross-contaminated throughout the entire slaughtering line. These results show that it is imperative to study the Campylobacter spp. from the yellow-feathered broiler along the slaughtering line in China to develop preventative and treatment measures for the poultry industry, as well as food safety and public health.

Management Strategies for Prevention of Campylobacter Infections Through the Poultry Food Chain: A European Perspective

Numerous studies point out that at present, a complete elimination of Campylobacter species in the poultry food chain is not feasible. Thus, the current aim should be to establish control measures and intervention strategies to minimize the occurrence of Campylobacter spp. in livestock (esp. poultry flocks) and to reduce the quantitative Campylobacter burden along the food chain in animals and subsequently in foods. The most effective measures to mitigate Campylobacter focus on the primary production stage. Nevertheless, measures applied during slaughter and processing complement the general meat hygiene approaches by reducing fecal contamination during slaughtering and processing and as a consequence help to reduce Campylobacter in poultry meat. Such intervention measures at slaughter and processing level would include general hygienic improvements, technological innovations and/or decontamination measures that are applied at single slaughter or processing steps. In particular, approaches that do not focus on a single intervention measure would need to be based on a thorough process of evaluation, and potential combinatory effects have to be modeled and tested. Finally, the education of all stakeholders (including retailers, food handlers and consumers) is required and will help to increase awareness for the presence of foodborne pathogens in raw meat and meat products and can thus aid in the development of the required good kitchen hygiene.

Current Status of Campylobacter Food Poisoning in Japan

According to the annual food poisoning statistics compiled by the Ministry of Health, Labour and Welfare (MHLW) in Japan, Campylobacter replaced Salmonella and Vibrio parahaemolyticus as the leading bacterium responsible for food poisoning in 2003. Although in 2006 the number of cases of Campylobacter food poisoning was 3,439 on the basis of the MHLW statistics, it was estimated to be 1,545,363 on the basis of active surveillance, suggesting that passive surveillance yields an incidence about 450 times lower than that revealed by active surveillance. Epidemiological investigations of Campylobacter food poisoning in Japan have shown that chicken meat and its products are the most important sources of infection, as is the case in other industrialized nations. Over the last two decades, the consumption of fresh raw chicken meat and liver has been increasing in Japan. Although the MHLW recommends that chicken meat should only be eaten after thorough cooking, it is likely to account for much of the increased incidence of human campylobacteriosis. In response to this situation, the Expert Committee on Microorganisms/Viruses, Food Safety Commission of Japan, Cabinet Office, Government of Japan (FSCJ) has revised the previous risk profile of C. jejuni/coli in chicken meat by adding new findings for 2018. Moreover, the MHLW revised the Poultry Slaughtering Business Control and Poultry Meat Inspection Act in 2014 aiming at stepwise introduction of the Hazard Analysis Critical Control Point (HACCP) system into poultry processing plants. Subsequently, the Japanese government amended the Food Sanitation Act in 2018, requiring all food business operators to implement hygiene control based on HACCP principles as a general rule. This paper reviews the current status of Campylobacter food poisoning due to consumption of chicken meat in Japan and extracts the issues underlying each step of the food supply chain in order to examine the implementation of effective measures for risk management.

Prevalence and Characteristics of Campylobacter Throughout the Slaughter Process of Different Broiler Batches

Handling and consumption of chicken meat are risk factors for human campylobacteriosis. This study was performed to describe the Campylobacter population in broiler carcasses and environmental samples throughout the slaughter process. Moreover, the genetic diversity and antimicrobial resistance of the Campylobacter strains were evaluated. Cloacal swabs, samples from carcasses at different stages, and environmental samples were collected thrice from the different flocks at the same abattoir located in Central Jiangsu, China. Campylobacter isolated from the three batches (n = 348) were identified as Campylobacter jejuni (n = 117) and Campylobacter coli (n = 151) by multiplex PCR. Characterization by multilocus sequence typing revealed a specific genotype of Campylobacter for each batch. Antimicrobial sensitivity to 18 antibiotics were analyzed for all selected strains according to the agar diffusion method recommended by the Clinical and Laboratory Standards Institute. Antibiotic susceptibility tests indicated that the majority of the tested isolates were resistant to quinolones (>89.7%). Less resistance to macrolide (59.8%), gentamicin (42.7%), amikacin (36.8%) was observed. Results showed that 94.0% of the tested strains demonstrated multidrug resistance.

Variation in Campylobacter Multilocus Sequence Typing Subtypes from Chickens as Detected on Three Plating Media

The objective of this study was to compare subtypes of Campylobacter jejuni and Campylobacter coli detected on three selective Campylobacter plating media to determine whether each medium selected for different subtypes. Fifty ceca and 50 carcasses (representing 50 flocks) were collected from the evisceration line in a commercial broiler processing plant. Campylobacter was cultured and isolated from cecal contents and carcass rinses on Campy-Cefex, Campy Line, and RF Campylobacter jejuni/coli agars. When a positive result was obtained with all three media, one colony of the most prevalent morphology on each medium was selected for further analysis by full genome sequencing and multilocus sequence typing. Sequence types were assigned according to PubMLST. A total of 49 samples were positive for Campylobacter on all three media. Forty samples contained only C. jejuni , three had only C. coli , and both species were detected in six samples. From 71% of samples, Campylobacter isolates of the same sequence type were recovered on all three media. From 81.6% of samples, isolates were all from the same clonal complex. From significantly fewer samples (26%, P < 0.01), one medium recovered an isolate with a sequence type different from the type recovered on the other two media. When multiple sequence types were detected, six times the medium with the odd sequence type was Campy-Cefex, four times it was Campy-Line, and six times it was RF Campylobacter jejuni/coli . From one sample, three sequence types were detected. In most cases, all three plating media allowed detection of the same type of Campylobacter from complex naturally contaminated chicken samples.

Campylobacter growth rates in four different matrices: broiler caecal material, live birds, Bolton broth, and brain heart infusion broth

Background

The objective of this study was to characterise Campylobacter growth in enrichment broths (Bolton broth, brain heart infusion broth), caecal material (in vitro), and in the naturally infected live broilers (in vivo) in terms of mean lag periods and generation times as well as maximum growth rates and population (cell concentration) achieved.

Methods

Bolton and brain heart infusion broths and recovered caecal material were inoculated with 10 poultry strains of Campylobacter (eight Campylobacter jejuni and two Campylobacter coli), incubated under microaerobic conditions, and Campylobacter concentrations determined periodically using the ISO 10272:2006 method. Caeca from 10 flocks, infected at first thinning, were used to characterise Campylobacter growth in the live birds. Mean generation times (G) (early lag to exponential phase) were calculated using the formula: G=t/3.3 logb/B. Mean lag times and µmax were calculated using the Micro Fit^© Software (Version 1.0, Institute of Food Research). Statistical comparison was performed using GENSTAT ver. 14.1 (VSN International Ltd., Hemel, Hempstead, UK).

Results

The mean lag periods in Bolton broth, brain heart infusion broth, caecal material, and in the live bird were estimated to be 6.6, 6.7, 12.6, and 31.3 h, respectively. The corresponding mean generation times were 2.1, 2.2, 3.1, and 6.7 h, respectively; maximum growth rates were 0.7, 0.8, 0.4, and 2 generations h⁻¹ and the maximum populations obtained in each matrix were 9.6, 9.9, 7.8, and 7.4 log₁₀ CFU/g, respectively.

Conclusion

This study provides data on the growth of Campylobacter in a range of laboratory media, caecal contents, and in broilers which may be used to develop predictive models and/or inform science-based control strategies such as the maximum time between flock testing and slaughter, logistical slaughter, and single-stage depopulation of broiler units.

Identification of risk factors for Campylobacter contamination levels on broiler carcasses during the slaughter process

Campylobacter carcass contamination was quantified across the slaughter line during processing of Campylobacter positive batches. These quantitative data were combined together with information describing slaughterhouse and batch related characteristics in order to identify risk factors for Campylobacter contamination levels on broiler carcasses. The results revealed that Campylobacter counts are influenced by the contamination of incoming birds (both the initial external carcass contamination and the colonization level of caeca) and the duration of transport and holding time that can be linked with feed withdrawal period. In addition, technical aspects of the slaughter process such as a dump based unloading system, electrical stunning, lower scalding temperature, incorrect setting of plucking, vent cutter and evisceration machines were identified as risk factors associated with increased Campylobacter counts on processed carcasses. As such the study indicates possible improvements of the slaughter process that can result in better control of Campylobacter numbers under routine processing of Campylobacter positive batches without use of chemical or physical decontamination. Moreover, all investigated factors were existing variations of the routine processing practises and therefore proposed interventions are practically and economically achievable.

Detection of Campylobacter DNA using magnetic nanoparticles coupled with PCR and a colorimetric end-point system

Campylobacter is an important food-borne pathogen causing acute gastroenteritis worldwide. Magnetic nanoparticle-based PCR coupled with streptavidin-horseradish peroxidase and a substrate was used for colorimetric detection. Forward primers conjugated to magnetic nanoparticles facilitated separation and concentration of Campylobacter DNA in a sample matrix. After PCR, a green color developed and was observed using the unaided eye, or detected using a spectrophotometer. High specificity and sensitivity of the 100 fg DNA/PCR reaction were achieved in pure culture experiments. The technique was applied for detection of Campylobacter on naturally contaminated chicken skin. All positive results were in agreement with results achieved using a conventional culture method. The magnetic nanoparticle-PCR-enzyme linked gene assay was practical and useful for detection of Campylobacter in complex matrices with PCR-interfering substances.

Prevalence of Salmonella and Campylobacter on broiler chickens from farm to slaughter and efficiency of methods to remove visible fecal contamination

A study was conducted to investigate the prevalence of Salmonella and Campylobacter from farm to slaughter. The efficiency of trimming and water spray (490 to 588 kPa pressure) on the removal of visible fecal contamination from broiler carcasses before chilling was also investigated. Drag swabs were used to sample litter from the farm houses. Samples of ceca and carcasses without and with visible fecal contamination before and after trimming or spray washing of fecal contamination were taken during slaughter of the flocks previously visited at the farms. There was a low prevalence of Salmonella on the litter from the farms (5%) and cecum and carcasses (0%). However, Campylobacter jejuni and Campylobacter coli were present in farms' litter (100 and 58.8%, respectively), cecum samples (100 and 70.6%, respectively), and carcasses with (58.8 and 11.6%, respectively) and without (17.6 and 9.8%, respectively) visible fecal contamination. There was high prevalence of C. jejuni but at low counts and low prevalence and high counts of C. coli. Campylobacter lari was not detected in any sample. Trimming the visible fecal contamination decreased the prevalence of C. jejuni but increased occurrence of C. coli. Trimming did not reduce the counts of Campylobacter and of hygiene indicator microorganisms on the carcasses. Water shower reduced the counts of hygiene indicator microorganisms by 20%. Therefore, control measures for preventing introduction of Campylobacter and the use of good hygienic conditions are needed to warrant the microbiological quality and safety of broiler carcasses.