Enumeration Of Campylobacter Research Articles

Implementation of a national monitoring programme of Campylobacter in Irish broilers to measure progress of on-farm and primary processing control measures.

Campylobacter is the most common food-borne pathogen in the European Union. In 2018, the crude incidence rate in Ireland was 63.6 per 100,000 population. Chicken is considered an important source of infection for humans. In 2015, the Campylobacter Stakeholders' Group (CSG) was established to reduce Campylobacter contamination levels in Irish broiler flocks. This work aimed to describe the Campylobacter monitoring programme that was established by the CSG, to analyse the results of this testing between 2019 and 2022, and to assess progress. This paper describes the monitoring programme that was established by the CSG, which harmonized Campylobacter enumeration testing across all Irish broiler processors and allowed comparability of results for trend analysis. An analysis of the 2019-2022 data is presented here and compared to previous studies of Campylobacter levels in Irish broilers. An analysis of the 2019-2022 data showed a significant reduction in levels in both caeca and neck skin when the results from 2022 were compared to those from 2019 to 2020. Campylobacter spp. were detected in 37% of caecal samples from first depopulation (pre-thin) broilers and 30% of neck skin samples in 2022, with just 4% of carcases (in neck skin samples) with ≥1000 colony-forming units per gram detected in 2022. Campylobacter levels detected in Irish broilers, in the present monitoring programme were less than those reported in previous studies in both caecal and carcase samples, although not directly comparable for statistical significance because of differences in study methods. The cooperation between stakeholders and regulators of the Irish broiler chicken industry over the past decade has facilitated a coordinated approach to monitoring of Campylobacter levels in broilers, and implementation of control measures. This has enabled a steady reduction in the levels of Campylobacter in Irish chicken.

Adaptation of a Commercial Qualitative BAX® Real-Time PCR Assay to Quantify Campylobacter spp. in Whole Bird Carcass Rinses.

Poultry is the primary reservoir of Campylobacter, a leading cause of gastroenteritis in the United States. Currently, the selective plating methodology using selective agars, Campy Cefex and Modified Charcoal Cefoperazone Deoxycholate agar, is preferentially used for the quantification of Campylobacter spp. among poultry products. Due to the specific nature of Campylobacter, this methodology is not sensitive, which can lead to skewed detection and quantification results. Therefore, Campylobacter detection and quantification methods are urgently needed. The objective was to develop a shortened enrichment-based quantification method for Campylobacter (CampyQuant™) in post-chill poultry rinsates using the BAX® System Real-Time PCR assay for Campylobacter. The specificity and sensitivity for the detection of C. jejuni, C. coli, and C. lari in pure culture were determined. The BAX® System Real-Time PCR assay consistently detected and identified each species 100% of the time with an enumeration range of 4.00 to 9.00 Log10 CFU/mL. Enrichment time parameters for low-level concentrations (0.00, 1.00, and 2.00 Log10 CFU/mL) of Campylobacter using the BAX® System Real-Time PCR assay were elucidated. It was determined that an enrichment time of 20 h was needed to detect at least 1.00 Log10 CFU/mL of Campylobacter spp. Using the BAX® System Real-Time PCR assay for Campylobacter. As a result, time of detection, detection limits, and enrichment parameters were used to develop the CampyQuant™ linear standard curve using the detected samples from the BAX® System Real-Time PCR assay to quantify the levels in post-chill poultry rinsates. A linear fit equation was generated for each Campylobacter species using the cycle threshold from the BAX® System Real-Time PCR assay to estimate a pre-enrichment of 1.00 to 4.00 Log10 CFU/mL of rinsates detected. The statistical analyses of each equation yielded an R2 of 0.93, 0.76, and 0.94 with a Log10 RMSE of 0.64, 1.09, and 0.81 from C. jejuni, C. coli, and C. lari, respectively. The study suggests that the BAX® System Real-Time PCR assay for Campylobacter is a more rapid, accurate, and efficient alternative method for Campylobacter enumeration.

Simultaneous Detection of Salmonella spp. and Quantification of Campylobacter spp. in a Real-Time Duplex PCR: Myth or Reality?

In Europe, there is a process hygiene criterion for Salmonella and Campylobacter on broiler carcasses after chilling. The criterion gives indicative contamination values above which corrective actions are required by food business operators. The reference methods for verifying compliance with the criterion for Salmonella and Campylobacter are international standards EN ISO 6579-1 (2017) and EN ISO 10272-2 (2017), respectively. These methods are time-consuming and expensive for food business operators. Therefore, it would be advantageous to simultaneously detect Salmonella spp. and quantify Campylobacter in the same analysis, using the same sample after the pre-enrichment step for Salmonella recovery. A duplex PCR for Salmonella detection and Campylobacter spp. enumeration was developed. Considering the method as a whole, the LOD and LOQ for Campylobacter enumeration were slightly over the limit of 3 log CFU/g set by the process hygiene criterion. A comparison of the duplex PCR method developed with the ISO method on artificially contaminated bacterial suspensions and on naturally contaminated samples demonstrated a good correlation of the results for Campylobacter enumeration when the duplex PCR was performed on samples taken before or after the pre-enrichment step, but revealed a slight bias with a large standard deviation resulting in widely spaced limits of agreement.

Quantification of Campylobacter contamination on chicken carcasses sold in retail markets in the United Arab Emirates

BackgroundCampylobacter is among the leading causes of foodborne zoonotic disease worldwide, with chicken meat accounting for the majority of human illnesses. This baseline study generates the first quantitative data for Campylobacter contamination in the United Arab Emirates chicken meat. Such data will help inform risk analysis and develop evidence-based food safety management.MethodsFor a year, chilled whole chicken carcasses (n = 315) belonging to seven different companies were collected from retail supermarkets. According to standard methods, Campylobacter enumeration was achieved by a direct plating in all chicken samples, and isolates were confirmed using multiplex PCR.ResultsCampylobacter spp. were recovered from 28.6% (90/315) of the samples. Campylobacter enumeration results indicated that 71.4% of the tested samples were contaminated with < 1 log10 CFU (colony-forming units)/g, and 7% were contaminated with ≥3 log10 CFU/g. The mean Campylobacter concentration was 2.70 log10 CFU/g, with a standard deviation of 0.41 log10 CFU/g. Campylobacter counts varied significantly in relation to the sourcing chicken processing companies. Six out of the seven surveyed companies provided Campylobacter positive samples. Moreover, significantly higher (p-value< 0.0001) counts were found to be associated with smaller size chicken carcasses (weighted 600–700 g; compared to the other categories, 800 g and 900–1000 g). Interestingly, C. coli was present in 83% of the positive samples, while C. jejuni was only detected in 6.4% of the samples. Compared with studies from other countries utilizing the same enumeration method, the UAE chicken appears to have a lower prevalence but a higher Campylobacter count per gram of carcasses. Higher Campylobacter counts were significantly associated with smaller carcasses, and C. coli was the dominant species detected in this study’s samples.ConclusionThese results add to our understanding of the local, regional and global epidemiology of Campylobacter in chicken meat. Outputs of the current study may aid in developing a risk assessment of Campylobacter in the UAE, a country among the biggest per capita consumption markets for chicken meat worldwide.

Rapid Oxford Nanopore Technologies MinION Sequencing Workflow for Campylobacter jejuni Identification in Broilers on Site—A Proof-of-Concept Study

Simple SummaryCurrent culture methods for Campylobacter enumeration in poultry meat require at least five days. To improve this outcome, we have assembled a portable sequencing kit consisting of the Bento Lab and the MinION and developed a workflow for on-farm use that can detect and report the presence of Campylobacter in less than five hours from sampling to data. In addition, this workflow allows for the determination of microbiota profiles within those five hours. Overall, this workflow and approach can be helpful in the control of zoonotic agents, with a particular focus on poultry meat, where it takes less than 24 h from the time the animals arrive at the slaughterhouse to the time the carcasses are available on the supermarket shelves.Campylobacter is recognised as one of the most important foodborne bacteria, with a worldwide health and socioeconomic impact. This bacterium is one of the most important zoonotic players in poultry, where efficient and fast detection methods are required. Current official culture methods for Campylobacter enumeration in poultry usually include >44 h of culture and >72 h for identification, thus requiring at least five working shifts (ISO/TS 10272-2:2017). Here, we have assembled a portable sequencing kit composed of the Bento Lab and the MinION and developed a workflow for on-site farm use that is able to detect and report the presence of Campylobacter from caecal samples in less than five hours from sampling time, as well as the relationship of Campylobacter with other caecal microbes. Beyond that, our workflow may offer a cost-effective and practical method of microbiologically monitoring poultry at the farm. These results would demonstrate the possibility of carrying out rapid on-site screening to monitor the health status of the poultry farm/flock during the production chain.

Research Note: Effect of a phlorotannin extract of the brown seaweed Ascophyllum nodosum as a potential control strategy against Campylobacter in broilers

Poultry is generally recognized as the main source of human campylobacteriosis and Campylobacter is highly prevalent at the farm level. To reduce the relative risk of human campylobacteriosis attributable to broiler meat, it is necessary to reduce Campylobacter loads in broiler ceca but to date, no effective, reliable and practical strategy is available. The marine environment is a rich source of original natural compounds exhibiting different biological activities. The objective of this study was to test a phlorotannin extract of the brown seaweed Ascophyllum nodosum as a potential control strategy against Campylobacter in broilers. Bactericidal activity has been demonstrated in vitro, on several Campylobacter spp. strains at a range of 0.06 to 0.47 mg/mL. Therefore, an in vivo trial in experimental facilities was performed to evaluate addition of 0.2% (w/w) of an A. nodosum extract to feed distributed at the end of rearing from day 31 to day 35, and to assess the effect on artificial Campylobacter jejuni colonization. No statistical differences in Campylobacter enumeration were observed between the treated and control groups. Another trial was performed in a commercial broiler flock. Feed containing the extract at 0.2% (w/w) (2 kg/t) was distributed during the last 5 days of rearing (day 33–day 38). No significant effects on Campylobacter colonization and on growth parameters were observed compared to the control group. Additional studies are needed to assess whether active polyphenols are found in the cecum.

On-site generated peroxy acetic acid (PAA) technology reduces Salmonella and Campylobacter on chicken wings

Peroxyacetic acid (PAA) is a widely used antimicrobial during poultry processing that requires to be shipped in a concentrated solution, stored under hazardous conditions and diluted for use. On-site PAA generation using nonhazardous ingredients can help eliminate transportation and storage issues at the processing plant and reduce the risk of occupational hazards. The objective of the proposed research was to 1) evaluate the efficacy of on-site generated PAA in reducing Salmonella and Campylobacter populations compared to the commercially available PAA stock solutions and 2) to perform color measurements to evaluate any deviations between treatments. PAA solutions at 50 and 100 ppm were used for treating the chicken wings. Fresh chicken wings (0.45 kg) were inoculated with a cocktail of nalidixic acid resistant Salmonella Typhimurium (STNR) and gentamicin resistant Campylobacter coli (CCGR) and immersed in PAA solutions (50 and 100 ppm) adjusted to pH 8.5 and 10.0 or 10.5, for either 10 s or 60 min. Treated chicken wings were rinsed for 1 min in chilled BPW (100 mL), serially diluted and plated on APC Petrifilm for Salmonella, spread plated on Campy-cefex agar supplemented with gentamicin (200 ppm) for Campylobacter enumeration. Immersion of chicken wings in 100 ppm PAA for 60 min irrespective of pH levels and PAA solutions resulted in greater microbial reductions (P < 0.05) of Salmonella by 1.68 and 1.42 log CFU/mL for SaniDate, 1.82 and 1.83 log CFU/mL for OxyFusion (on-site generated). For the same treatments, Campylobacter reductions of 1.59 and 1.36 log CFU/mL for SaniDate, 1.63 and 1.71 log CFU/mL for OxyFusion were achieved. The antimicrobial efficiency of PAA was not affected by pH and type of PAA solution. No significant differences (P > 0.05) in color were observed between treatments and controls. On-site generated PAA provides poultry processors an effective, safer, and less hazardous alternative to commercially available PAA solutions, ensuring poultry workers’ health and safety.

Prevalence of Campylobacter spp. in Chicken Carcasses in Slaughterhouses from South of Brazil.

Campylobacteriosis has become common cause of diarrhea in humans and is associated with Guillain-Barré Syndrome, Reactive Arthritis and Irritable Bowel Syndrome is caused mainly by contaminated food and water intake in which the majority occurs from manipulation, preparation and consumption of poultry meat. The aim of this study was to estimate the prevalence of Campylobacter in chicken carcasses from slaughterhouses located in the states of Parana, Santa Catarina and Rio Grande do Sul in the South of Brazil. The samples were analyzed for Campylobacter enumeration using the ISO method 10272-2 and the species C. jejuni and C. coli, important for public health, were identified through Maldi-TOF mass spectrometry. From July 2017 to July 2018, 816 samples were analyzed, indicating the prevalence of 35.84%, with higher occurrence of C. jejuni (78.47%). No difference in prevalence was observed in relation to the size of the slaughterhouses. However, significant differences were noted among the three states in the southern region of the country, with the lowest prevalence being observed in Parana. The results reinforce the need to advance in the implementation of strategies to control this pathogen in the country, in order to safeguard consumer's health and contribute for the maintenance of Brazil's position in the international poultry meat market.

Prevalence and Genotyping of Campylobacter jejuni and Campylobacter coli from Ovine Carcasses in New Zealand

A pilot survey was performed to determine the prevalence of Campylobacter jejuni and Campylobacter coli on three age classes (lamb, hogget, and mutton) of ovine carcass trim postdressing and prechill. Sampling of hogget carcasses was undertaken 6 months before sampling of lamb and mutton carcasses. A total of 120 trim samples were collected from 11 processing plants across New Zealand. All samples were enriched and screened using PCR for the presence of C. jejuni and C. coli, and isolation was attempted for all screen-positive samples. Enumeration of Campylobacter from lamb trim samples showed that Campylobacter bacteria were present in very low numbers (<10 CFU/g). The overall prevalence of Campylobacter for ovine trim based on PCR detection was 33% (39 of 120 samples), with prevalences for hogget, lamb, and mutton carcass trim of 56% (28 of 50), 11% (4 of 35), and 20% (7 of 35), respectively. Whole genome sequencing was performed on a selection of C. jejuni and C. coli isolates, and the data were used to subtype using multilocus sequence typing (MLST) and whole genome MLST. Twenty-five MLST sequence types (STs) were identified among 44 isolates, including ST42, ST50, ST3222, and ST3072, which have been previously reported to be associated with ruminant sources. Four novel STs were also identified. Whole genome MLST analysis further discriminated isolates within a single ST type and demonstrated a genetic diversity among the ovine isolates collected. Genes associated with the oxacillinase class of β-lactamase enzymes were identified in 41 of 44 Campylobacter isolates. This study provides preliminary data that can be incorporated into existing source attribution models to assist in determining the potential contribution of ovine sources to the burden of campylobacteriosis in New Zealand.

Proficiency-Testing Scheme for Detection and Enumeration of Campylobacter in Poultry Meat

Proficiency-Testing Scheme for Detection and Enumeration of Campylobacter in Poultry Meat

Can animal welfare have an impact on food safety? A study in the poultry production chain

Abstract Background Animal welfare is a major issue in the production of food of animal origin. A project funded by the Italian Ministry of Health was carried out in order to collect scientific evidence that animal welfare is not only an ethical issue, but should also be related to food safety. Methods The project was carried out along an Italian integrated poultry production chain. Animal welfare was measured at farm in 13 broiler chicken batches, including 2 organic, using Welfare Quality®, an animal- and resource-based internationally recognised protocol. Samples for the detection and enumeration of Campylobacter, Salmonella and Listeria monocytogenes were taken at different levels, from the live animal (faeces at farm and after transport) to the end product (caecal content and carcass skin at slaughterhouse), with a total of 2,080 samples. Strains were deeply characterised (serotyping, PFGE). Results Higher welfare scores were reported in organic batches. Transports to the slaughterhouse longer than 1 hour were associated to increased Campylobacter prevalence. Significantly lower Campylobacter concentrations both in faeces and carcass (P &amp;lt; 0.05) were reported in organic batches. Low-welfare batches showed higher prevalence of Salmonella, with statistically significant difference compared to high-welfare batches (43.6% versus 2.9% in carcass; 19.3% versus 0% in caecal content; P &amp;lt; 0.00001). L. monocytogenes was never found in faeces, in contrast with high prevalence in carcases (up to 72.5%) with undistinguishable genetic profiles recurrent in different batches after long time (up to 18 months). Conclusions Our results support the hypothesis that poultry meat contamination is influenced by the welfare or stress which broilers experience during their life. Longer transports enhance Campylobacter prevalence. L. monocytogenes in poultry meat should not be linked to increased stress but rather to persistent contamination in the slaughterhouse processing environment. Key messages “High-welfare” broiler chicken batches show lower Campylobacter and Salmonella contamination compared to “Low-welfare” batches. Microbiological safety of poultry meat can be improved by the application of high animal welfare standards at farm and during transport.

Campylobacter prevalence and risk factors associated with exceeding allowable limits in poultry slaughterhouses in Spain

BackgroundCampylobacter is the main pathogen involved in zoonotic gastrointestinal diseases. In 2018, European Regulation 2017/1495 on Campylobacter in broiler carcases came into force. In this context, the aim of the...

Effect of a direct-fed microbial and prebiotic on performance and intestinal histomorophology of turkey poults challenged with Salmonella and Campylobacter

Salmonella and Campylobacter are leading human foodborne pathogens commonly associated with poultry and poultry products, and several methods to control these pathogens have been applied to poultry production. This study was conducted to evaluate the effect of CALSPORIN, (CSP), a direct-fed microbial (DFM), and yeast cell wall (Saccharomyces cervisiae, IMW50, a mannanoligosaccharide (MOS)-based prebiotic, on performance, levels of Salmonella and Campylobacter in the feces, and intestinal histomorphometry in turkey poults. A 21-day battery cage study was conducted using 4 dietary treatments, including: an unsupplemented basal diet (corn and soybean-based) as negative control (NC); basal diet supplemented with 0.05% DFM; basal diet supplemented with 0.05% MOS; and basal diet supplemented with 0.05% mixture of DFM and MOS at equal proportions. Female Large White turkey poults (n = 336) were randomly distributed in 6 electrically-heated battery cages with 4 treatments and 12 replicates per treatment (7 poults per replicate pen). The first 16 pens were not inoculated with bacteria, while poults in pens 17 to 32 were orally challenged at day 7 with 105 CFU Salmonella Heidelberg and the poults in pens 33 to 48 were orally challenged at day 7 with 105 CFU Campylobacter jejuni. Feed consumption, body weight, and feed conversion ratio were measured weekly and at the end of the experiment. At day 21, fresh fecal samples from each pen were collected for Salmonella and Campylobacter enumeration and ileal tissue samples were collected from 1 bird per pen for histomorphology examination. DFM and MOS supplementation was accompanied with reduced levels of Salmonella shed by the treated birds compared to the control group, and with increased body weight (P ≤ 0.05). The surface area of villi increased in the MOS-supplemented group compared to the control group (P ≤ 0.05). There was a significant difference in V:C ratio between supplemented groups and control group (P ≤ 0.05). Based on these results, there is potential for CALSPORIN and IMW50 to reduce Salmonella shedding in feces, enhance ileal mucosal health, and improve growth performance of turkey poults.

Animal welfare and microbiological safety of poultry meat: Impact of different at-farm animal welfare levels on at-slaughterhouse Campylobacter and Salmonella contamination

Stress factors and poor animal welfare can increase the susceptibility of food-producing animals to diseases, posing microbial risks to consumers. Animal welfare levels, objectively measured with the application of the Welfare Quality® protocol, were assessed in thirteen broiler flocks, including organic ones, to evaluate the presence of statistically significant differences in relation to Campylobacter and Salmonella faecal shedding and consequent microbiological contamination of broiler carcases at slaughterhouse. Each flock underwent animal welfare evaluation the day before slaughtering, followed by Campylobacter and Salmonella detection in faeces (caecal content) and neck skin at slaughterhouse. A total of 1040 samples (520 caecal contents; 520 neck skins) were included in the study. Campylobacter enumeration and Salmonella serotyping were also carried out. The highest welfare scores were reported in organic flocks. Significantly lower Campylobacter concentrations both in caecal content and neck skins (P < 0.05) were reported in organic batches, compared to high welfare conventional batches. Low-welfare batches showed higher prevalence of Salmonella both in neck skins and caecal content, with a statistically significant difference compared to high-welfare batches (43.6% versus 2.9% in neck skins; 19.3% versus 0% in caecal content; P < 0.00001). Salmonella Infantis and Salmonella Bredeney were the most common serotypes, while Campylobacter jejuni and Campylobacter coli were the detected species.This study provides new evidence that high animal welfare standards at farms, other than an ethical issue and a value-add for the end product, could also improve the microbiological safety of poultry meat, ultimately contributing to the protection of consumers.

Intestinal colonization and acute immune response in commercial turkeys following inoculation with Campylobacter jejuni constructs encoding antibiotic-resistance markers

Consumption of contaminated poultry products is one of the main sources of human campylobacteriosis, of which Campylobacter jejuni subsp. jejuni (C. jejuni) is responsible for approximately 90% of the cases. At slaughter, the ceca of commercial chickens and turkeys are the main anatomical site where C. jejuni asymptomatically colonizes. We have previously colonized commercial turkey poults with different isolates of C. jejuni and evaluated different media to best enumerate Campylobacter from intestinal samples, but the host-response is unknown in turkeys. Enumeration of Campylobacter (colony forming units (cfu)/gram of intestinal contents) can be challenging, and can be confounded if animals are colonized with multiple species of Campylobacter. In order to precisely enumerate the C. jejuni isolate used to experimentally colonize turkeys, constructs of C. jejuni (NCTC 11,168) were tagged with different antibiotic resistance markers at the CmeF locus (chloramphenicol (CjCm) or kanamycin (CjK)). We sought to examine the kinetics of intestinal colonization using the antibiotic resistant constructs, and characterize the immune response in cecal tissue of turkeys. In vitro analysis of the tagged antibiotic-resistant constructs demonstrated no changes in motility, morphology, or adherence and invasion of INT-407 cells compared to the parent isolate NCTC 11,168. Two animal experiments were completed to evaluate intestinal colonization by the constructs. In experiment 1, three-week old poults were colonized after oral gavage for 14 days, and CjCm and CjK cfu were recovered from cecal, but not ileal contents. In experiment 2, nine-week old poults were orally inoculated with CjCm, and the abundance of CjCm cfu/g of cecal contents significantly decreased beyond 14 days after inoculation. Significant lesions were detected in CjCm colonized poults at day 2 post-colonization. Using immunohistochemistry, Campylobacter antigen was detected in between cecal villi by day 7 of CjCm colonized poults. Quantitative RT-PCR of CjCm-colonized cecal tissue demonstrated significant down-regulation of IL-1β, IL-10 and IL-13 mRNA, and significant up-regulation of IL-6, IL-8, IL-17 A, IL-22 and IFNγ mRNA on day 2, and for some on day 7 post-colonization. All differentially expressed genes were similar to mock-infected poults by day 14. These data suggest that C. jejuni induced a brief inflammatory response in the cecum of poults that quickly resolved. Results from this study provide valuable insight into host-response and persistent colonization of the turkey cecum. These findings will help to develop and test strategies to promote food safety in commercial turkeys.

Campylobacter contamination level in houseflies after exposure to materials containing Campylobacter

Although houseflies have been found to carry Campylobacter jejuni, little is known about the quantitative campylobacter level in naturally contaminated houseflies and their ability to contaminate surfaces. This study aimed to elucidate how houseflies’ previous exposure to campylobacter-contaminated material (faeces or liquid) for 1 or 4 h affects the acquired campylobacter level in houseflies and their contamination potential. Cups of 250 ml were added 5 g of chicken faeces or 1 ml liquid and spiked with approximately 3, 4, 5 or 7 log10 cfu C. jejuni. Sixteen houseflies were added to each cup. After 1 h of exposure, four houseflies were removed from the cup for enumeration of campylobacter in each fly by plate spreading. Another four houseflies were transferred onto Abeyta-Hunt-Bark (AHB) agar plates (9 cm) to assess possible contamination of surfaces. After 1 h on the AHB plate, each fly was tested for level of campylobacter. This procedure was repeated after approx. 4 h of exposure for the remaining eight houseflies. The C. jejuni acquisition in houseflies increased with exposure dose and was higher after liquid exposure compared with faeces exposure, while there was no significant effect of exposure time (1 vs 4 h). For faeces, 90.0% (n=80), 48.4% (n=64), 6.3% (n=48) and 0% (n=16) of houseflies were campylobacter-positive when exposed to 7, 5, 4, and 3 log10 cfu with a mean (±SE) of 2.0±0.1, 0.8±0.1, 0.3±0.0 and 0 log10 cfu recovered per campylobacter-positive fly, respectively. For liquid, 95.7% (n=47), 91.4% (n=47), 20.8% (n=48) and 6.3% (n=16) of houseflies were campylobacter-positive with a mean of 3.3±0.2, 2.0±0.1, 0.8±0.2 and 0.3±0.0 log10 cfu. The surface of the AHB plates was only contaminated by houseflies previously exposed to &gt;4 log10, but the C. jejuni number found on the AHB surface did not correlate with the number found in the corresponding fly.

Exposure to whole chicken carcasses may present a greater risk of campylobacteriosis compared to exposure to chicken drumsticks.

In New Zealand, the major risk factor for campylobacteriosis has been identified as poultry consumption. New Zealanders consume different types of chicken meat which undergo different processing before entering the retail chain. The manipulations and jointing of chicken carcasses into pieces and the subsequent processing and packaging have the potential to cross-contaminate and reshuffle bacterial pathogens among the different products sold. The aim of this study was to analyse: (a) the differences in the viable count and population genetic structure between Campylobacter isolated from chicken drumsticks and whole carcass meat for retail sale over a 1-year period; and (b) the genetic relatedness of human and chicken isolates collected concurrently. Enumeration of Campylobacter was performed using a spiral plater combined with manual spread plating. Campylobacter isolates were identified by polymerase chain reaction and typed bymultilocus sequence typing (MLST). C.jejuni was the dominant species among both whole carcasses (63.5%) and drumsticks samples (73.8%), followed by C.coli (27% and 23.1%, respectively). After sample weight adjustment, whole carcasses showed significantly higher Campylobacter counts than drumsticks, with a significant difference in the counts between the commercial suppliers in both types of retail meat. MLST revealed 28 different sequence types among the two types of meat. Using permutational multivariate analysis of variance, statistically significant differences in the population genetic structures were observed between different suppliers but were not observed between the two types of chicken retail meat. In conclusion, we found differences in Campylobacter viable counts, suggesting consumption of whole carcasses may determine an exposure to a higher number of Campylobacter bacteria than consumption of chicken drumsticks. The Campylobacter population genetic structure did not differ between the two types of chicken retail meat. Therefore, source attribution studies based on MLST are unlikely to be biased by the selection of these types of retail meat during sampling.

Validation by interlaboratory trials of EN ISO 10272 - Microbiology of the food chain - Horizontal method for detection and enumeration of Campylobacter spp. - Part 1: Detection method

During the last decade Campylobacter has been the most commonly reported gastrointestinal bacterial infection in humans in the European Union. The use of a sensitive detection method based on enrichment of Campylobacter spp. is often needed when examining foods. However, as background flora developed resistance to third generation β-lactams used in selective culture media, the ISO method was adapted. It now consists of three different procedures (A, B, and C) depending on the expected concentration and condition of Campylobacter and the background microflora. As the diagnostic sensitivity of the detection test varies between laboratories, this justifies the validation of the method in an interlaboratory study.The matrices selected for testing in the collaborative trials were frozen spinach (procedure A, Bolton enrichment broth), minced meat (procedure A, Bolton enrichment broth), raw milk (procedure B, Preston enrichment broth), chicken skin (procedure B, Preston enrichment broth), and broiler caecal material (procedure C, direct plating on mCCD agar). Each matrix was artificially inoculated with a different Campylobacter strain at a low and high contamination level, and with sterile diluent for ‘blanks’. Seventeen laboratories participated in the interlaboratory study. The sensitivity and specificity of the methods for the five selected matrices were determined, as well as the level of detection (LOD50). Calculated LOD50 values ranged from 0.84 cfu/test portion in frozen spinach and 2.2 cfu/test portion in minced meat to 14 cfu/test portion in chicken skin and 57 cfu/test portion in raw milk, all based on test portions of 10 g. The test portion size for broiler caecal material was a 10 μl-loop, yielding a LOD50 of 6.1 cfu/test portion. The validation data were incorporated in the newly published ISO standard EN ISO 10272-1:2017 - Microbiology of the food chain - Horizontal method for detection and enumeration of Campylobacter - Part 1: Detection method.

Validation by interlaboratory trials of EN ISO 10272 - Microbiology of the food chain - Horizontal method for detection and enumeration of Campylobacter spp. - Part 2: Colony-count technique

The validation in an interlaboratory study of the International Standards Organization standard method for the enumeration of Campylobacter in foods (ISO 10272-2) was performed after preparation of the revised Standard based on scientifically sound and validated methods of analysis.The matrices selected for testing in the collaborative trial were frozen spinach, minced meat, raw milk, chicken skin, and broiler caecal material. Each matrix was artificially inoculated with a different Campylobacter strain. Fifteen laboratories participated in the interlaboratory study.As a general indication of repeatability limit (r), the following overall values can be used when testing chicken skin samples:r = 0.98 (expressed as a difference between log10-transformed test results), orr = 9.52 (expressed as a ratio between test results).As a general indication of reproducibility limit (R), the following overall values can be used when testing chicken skin samples:R = 1.31 (expressed as a difference between log10-transformed test results), orR = 20.43 (expressed as a ratio between test results).The validation data for all matrices were incorporated in the newly published ISO standard EN ISO 10272-2:2017 - Microbiology of the food chain - Horizontal method for detection and enumeration of Campylobacter - Part 2: colony-count technique.

β-Resorcylic Acid, a Phytophenolic Compound, Reduces Campylobacter jejuni in Postharvest Poultry

Human Campylobacter infections, a leading foodborne illness globally, has been linked with the high prevalence of this bacterium on raw retail chicken products. Reduction of Campylobacter counts on poultry products would greatly reduce the risk of subsequent infections in humans. To this end, this study investigated the potential of the phytophenolic compound β-resorcylic acid (BR) to reduce Campylobacter counts on postharvest poultry (chicken skin or meat). Four trials in total, two each on thigh skin or breast meat, were conducted in which chicken skin or meat samples (2 ± 0.1 g; 10 samples per treatment) were inoculated with 50 μL (∼106 CFU per sample) of a cocktail of four wild strains of C. jejuni. After 30 min of attachment, inoculated samples were dipped in a 0, 0.5, 1, or 2% BR solution for 30 s immediately followed by vigorously vortexing the samples in Butterfield's phosphate diluent and plating the supernatant for Campylobacter enumeration. In addition, the effect of BR on the color of skin and meat samples was studied. Moreover, the change in the expression of survival and virulence genes of C. jejuni exposed to BR was evaluated. Data were analyzed by the PROC MIXED procedure of SAS (P < 0.05; SAS Institute Inc., Cary, NC). All BR treatments significantly reduced Campylobacter populations on both chicken or meat samples by 1 to 3 log CFU/g compared with non-BR-treated washed controls. No significant difference in the lightness, redness, and yellowness of skin and meat samples was observed on exposure to BR wash (P > 0.05). Real-time PCR results revealed that BR treatment down-regulated expression of select genes coding for motility (motA, motB) and attachment (cadF, ciaB) in the majority of C. jejuni strains. Stress response genes (sodB, katA) were upregulated in C. jejuni S-8 (P < 0.05). Overall, our results suggest that BR could be effectively used as antimicrobial dip treatment during poultry processing for reducing Campylobacter on chicken carcasses.