Effect of External or Internal Fecal Contamination on Numbers of Bacteria on Prechilled Broiler Carcasses

Bacteriophage cocktail application for Campylobacter mitigation - from in vitro to in vivo

BACKGROUND

Effective strategies are urgently needed to control Campylobacteriosis, one of the most important foodborne gastrointestinal diseases worldwide. Administering bacteriophages (phages) is under evaluation as a possible intervention strategy in primary poultry production to reduce the public health risk of human infection. A major challenge is the translation of results from small-scale animal studies to large broiler flocks. In this study, the in vitro lytic activity of 18 Campylobacter-specific group II phages and 19 group III phages were examined singly, and in different combinations from the same group and from both groups using a planktonic killing assay. Based on these results, a combination of phage NCTC 12,673 (group III) and vB_CcM-LmqsCPL1/1 (group II) was selected for in vivo application in a seeder bird model to study its effectiveness under conditions as close as possible to field conditions. One hundred eighty Ross 308 broiler chickens were divided into a control and a treatment group. Ten days post hatch, seeder birds were orally inoculated with the C. jejuni target strain. Phages were administered via drinking water at a total concentration of 107 PFU/mL four, three, and two days before necropsy.

RESULTS

Combining group II and group III phages resulted in significantly higher in vitro growth inhibition against the C. jejuni target strain BfR-CA-14,430 than single application or combinations of phages from the same group. The results of the animal trial showed that the application of the two phages significantly reduced Campylobacter counts in cloacal swabs. At necropsy, Campylobacter counts in colonic content of the treatment group were significantly reduced by 2 log10 units compared to the control group.

CONCLUSIONS

We demonstrated that combining phages of groups II and III results in significantly increased lytic activities. The in vitro results were successfully translated into practical application in a study design close to field conditions, providing new data to apply phages in conventional broiler flocks in the future. Phage application reduced the fecal Campylobacter excretion and Campylobacter concentrations in the colon of broilers.

Antimicrobial effect of a drinking water additive comprising four organic acids on Campylobacter load in broilers and monitoring of bacterial susceptibility

Application of organic acids via feed or drinking water is under discussion as a possible intervention strategy to reduce Campylobacter (C.) load in primary poultry production. A previous in vitro study showed that reduced concentrations of sorbic acid, benzoic acid, propionic acid, and acetic acid were required for antibacterial activity against Campylobacter when using a mixture of these 4 acids compared to when using the single acids. The present study aimed at determining the antibacterial efficiency of this combination in vivo as a drinking water additive for reducing shedding and intestinal C. jejuni colonization in broilers. Furthermore, we assessed whether the inoculated C. jejuni strain BfR-CA-14430 adapted in vivo to the applied organic acids. Results of this study showed that adding the organic acids consistently reduced Campylobacter loads in cloacal swabs. While significant reductions were observed within the entire study period, a maximum 2 log reduction occurred at an age of 18 d. However, after dissection at the end of the trial, no significant differences were detected in Campylobacter loads of cecal and colon contents compared to the control group. Susceptibility testing of re-isolates from cloacal swabs and cecal content revealed equal minimum inhibitory concentration (MIC) values compared to the inoculated test strain, suggesting that C. jejuni remained susceptible throughout the trial.

Influence of pre-slaughter fasting time on weight loss, meat quality and carcass contamination in broilers

Objective

An experiment was conducted to determine the appropriate fasting time prior to slaughter for broilers in floor-feed and scatter-feed mode.

Methods

On 21 d since hatching, 120 Arbor Acres broilers were divided into floor-feed and scatter-feed groups, chicks from each group were further assigned to feed withdrawal treatments for 0, 4, 6, 8, and 10 h. Some resultant indicators such as carcass contamination, body weight loss, meat quality of 54-day-old broilers were measured.

Results

It appears that longer feed withdrawal increased weight loss, lightness, drop loss of meat but reduced pH. A significant higher weight loss and lightness for both floor-feed and scatter-feed chicks coincided after 6 to 10 h feed withdrawal (p<0.05). pH for breast muscle at 45 min postmortem reduced when chicks of scatter-feed were fasted 6 and 10 h, while the reduction of floor-feed group occurred only in 10 h (p<0.05). A noticeable effect of feed withdrawal on drop loss occurred after 10 h fasting in scatter-feed of which drop loss were significantly higher than that for other groups including control (p<0.05). The change of contamination propensity revealed that 6 to 10 h fasting significantly reduced the likelihood of carcass contamination under both floor-feed and scatter-feed (p<0.05). Net weights of intestinal contents for gizzard were significantly reduced after feed deprived for 10 h in floor-feed and 6 and 10 h in scatter-feed (p<0.05). The decrease for whole intestine occurred after floor-feed broilers have been without feed for more than 4 h, scatter-feed broilers for more than 8 h (p<0.05).

Conclusion

On the premise that poultry product properties and welfare were not significantly damaged, proper fasting time could reduce carcass contamination. Current data implied that 6 h fasting was recommendable for both floor and scatter feed pre-slaughter broilers.

Comparative efficacy of spray-dried plasma and bacitracin methylene disalicylate in reducing cecal colonization by Salmonella Enteritidis in broiler chickens

Spray-dried plasma (SDP) contains immunoglobulins and glycoproteins that possess antibacterial properties. Two floor-pen trials were conducted to determine the efficacy of dietary SDP and bacitracin methylene disalicylate (BMD) antibiotic in reducing intestinal colonization by Salmonella Enteritidis (SE) in broiler chickens. Experiment 1 was a 2-wk, 3 × 2 factorial design consisting of 6 treatments. Treatment CON consisted of chicks fed unmedicated corn-soybean meal (SBM) basal without SDP. Treatment BMD consisted of chicks given unmedicated corn-SBM basal into which BMD was added at 0.055g/kg diet. Treatment SDP consisted of chicks given unmedicated corn-SBM basal into which SDP was added at 30g/kg diet. Treatments CON-SE, BMD-SE, and SDP-SE consisted of chicks that were given diets similar to CON, BMD, and SDP, respectively, and were each inoculated with 7.46 × 10⁸ CFU SE /mL at 1 day of age. Experiment 2 was a 42-day trial that was similar to Experiment 1 in design, except that chicks were placed on fresh clean litter. On d 3, 7, 14, and 28 post-challenge (PC), ceca SE concentration was enumerated on xylose lysine tergitol-4 (XLT4) agar. Body weight gain (BWG) and feed conversion ratio (FCR) were also recorded. Results for d 3 showed that BMD- and SDP-fed chicks had similar (P > 0.05) cecal SE (3.39 log ₁₀ CFU / g and 3.58 log ₁₀ CFU / g, respectively), but these levels were lower (P < 0.05) than that of CON-fed chicks (5.68 log ₁₀ CFU / g). A similar trend was observed on d 7 and 14 PC. The BMD- and SDP-fed chicks also had higher BWG and FCR (P < 0.05) when compared with CON-fed chicks up to d 14. Thereafter, only BMD treatment sustained this growth-promoting effect till d 42 in SE-challenged birds. In conclusion, BMD and SDP showed similar efficacy in reducing cecal Salmonella and in mitigating consequent growth-depressing effect(s) in broiler chicks up to 2 wk of age.

Genotypic Characterization of Antimicrobial Resistant Salmonella spp. Strains from Three Poultry Processing Plants in Colombia

The poultry industry in Colombia has implemented several changes and measures in chicken processing to improve sanitary operations and control pathogens’ prevalence. However, there is no official in-plant microbial profile reference data currently available throughout the processing value chains. Hence, this research aimed to study the microbial profiles and the antimicrobial resistance of Salmonella isolates in three plants. In total, 300 samples were collected in seven processing sites. Prevalence of Salmonella spp. and levels of Enterobacteriaceae were assessed. Additionally, whole-genome sequencing was conducted to characterize the isolated strains genotypically. Overall, the prevalence of Salmonella spp. in each establishment was 77%, 58% and 80% for plant A, B, and C. The mean levels of Enterobacteriaceae in the chicken rinsates were 5.03, 5.74, and 6.41 log CFU/mL for plant A, B, and C. Significant reductions were identified in the counts of post-chilling rinsate samples; however, increased levels were found in chicken parts. There were six distinct Salmonella spp. clusters with the predominant sequence types ST32 and ST28. The serotypes Infantis (54%) and Paratyphi B (25%) were the most commonly identified within the processing plants with a high abundance of antimicrobial resistance genes.

Thyme Oil Enhances the Inactivation of Salmonella enterica on Raw Chicken Breast Meat During Marination in Lemon Juice With Added Yucca schidigera Extract

Enteric pathogens such as Salmonella enterica can survive in low pH conditions and pose a food safety threat during marinating of raw poultry meat. A study was conducted to investigate the effectiveness of thyme oil for killing S. enterica on raw chicken during marination in lemon juice containing yucca extract. Samples of raw chicken breast were inoculated with a five-serovar mixture of S. enterica (~10⁸ CFU/mL) and immersed for 2, 4, 6, and 8 h in four lemon-based marinades at 22°C: lemon juice alone (L), L with added 0.5% yucca extract (L + Y), L + Y and 0.5% thyme oil (L + Y + 0.5% TO) and L + Y + 1.0% TO. The L and L + Y served as controls. Survivors were determined by surface plating chicken homogenates on xylose-lysine tergitol-4 (XLT4) agar and XLT4 agar overlaid with non-selective agar (TAL) and counting bacterial colonies after 48 h of incubation (35°C). Marinades containing Y and TO significantly reduced initial viable populations of S. enterica compared to control (L and L + Y) solutions (P < 0.05). Based on S. enterica survivors on TAL medium, the L and L + Y reduced initial populations by 1.12 and 1.42 Log CFU/sample, respectively, after 8 h whereas, Log reductions caused by L + Y + 0.5% TO and L + Y + 1.0% TO, respectively, were 2.62 and 3.91 (P < 0.05). Numbers of survivors were higher on TAL compared to XLT4 agar (P < 0.05); however, the extent of sub-lethal injury caused by the marinades was not statistically significant (P > 0.05). The death rate of S. enterica increased significantly (P < 0.05) in the marinades containing TO (0.5 or 1.0%) compared to control (L + Y). Based on these results, thyme oil has good potential to increase the antimicrobial efficacy of lemon juice marinade against Salmonella on raw chicken breast and enhance the microbial safety of this popular poultry product.

Aerobic plate count, Salmonella and Campylobacter loads of whole bird carcass rinses from pre-chillers with different water management strategies in a commercial poultry processing plant

Salmonella and Campylobacter are significant issues for poultry processors because of increasing regulatory standards as well as public health concerns. The goal of this study is to report the effects of two different pre-chiller systems that utilize different temperatures and water recirculation systems on whole bird carcass rinsates. Both pre-chiller tanks were contained within a single poultry processing facility and operated at different temperatures and water systems. The incidence of Campylobacter spp. and Salmonella spp., as well as the aerobic plate counts on whole bird carcass rinses are reported in this study from each pre-chiller system. The results from this study reveal that there are significant differences in how microbial populations and pathogens change over time in each pre-chiller system. Furthermore, we identify that these patterns are different per system. Such data are impactful as it indicates that measuring carcasses within a plant must consider both temperature and water recirculation as it may prevent comparability of different lines within a single processing facility.

Prevalence of Campylobacter spp. in Poultry in Three Spanish Farms, A Slaughterhouse and A Further Processing Plant

The present study was conducted to investigate the prevalence of Campylobacter spp. in a selection of poultry flocks and the corresponding broiler carcasses as well as the possible impact of contamination during slaughter and processing. Samples of the same flock at different ages in three farms (A, B and C) were taken for the determination of Campylobacter spp. The same broiler flocks were examined at different stages of one slaughterhouse and at a further processing plant. The slaughterhouse environment and processing equipment were sampled. Campylobacter spp. was not detected in 7 and 14-day-old broilers in any of the three farms studied. However, Campylobacter spp. was detected in 35 and 42-day-old broilers at two farms (Farm A and B). This pathogen was detected in both dirty and clean transport crates, in scalding water, and on the defeathering machine and the working table at the end of the working day, but not at the beginning. After defeathering, Campylobacter spp. was detected in all of the sampled carcasses. Campylobacter spp. was detected in all of the carcasses and the poultry meat portion samples from Farm C, although it was not detected at the farm level. This suggests that Campylobacter spp. infected flocks may be a source of these bacteria in the corresponding carcasses, but a cross-contamination during the transportation and slaughter process is also very important.

Reviewing Interventions against Enterobacteriaceae in Broiler Processing: Using Old Techniques for Meeting the New Challenges of ESBL E. coli?

Extended-spectrum beta-lactamase- (ESBL-) producing Enterobacteriaceae are frequently detected in poultry and fresh chicken meat. Due to the high prevalence, an impact on human colonization and the spread of antibiotic resistance into the environment is assumed. ESBL-producing Enterobacteriaceae can be transmitted along the broiler production chain but also their persistence is reported because of insufficient cleaning and disinfection. Processing of broiler chickens leads to a reduction of microbiological counts on the carcasses. However, processing steps like scalding, defeathering, and evisceration are critical concerning fecal contamination and, therefore, cross-contamination with bacterial strains. Respective intervention measures along the slaughter processing line aim at reducing the microbiological load on broiler carcasses as well as preventing cross-contamination. Published data on the impact of possible intervention measures against ESBL-producing Enterobacteriaceae are missing and, therefore, we focused on processing measures concerning Enterobacteriaceae, in particular E. coli or coliform counts, during processing of broiler chickens to identify possible hints for effective strategies to reduce these resistant bacteria. In total, 73 publications were analyzed and data on the quantitative reductions were extracted. Most investigations concentrated on scalding, postdefeathering washes, and improvements in the chilling process and were already published in and before 2008 (n=42, 58%). Therefore, certain measures may be already installed in slaughterhouse facilities today. The effect on eliminating ESBL-producing Enterobacteriaceae is questionable as there are still positive chicken meat samples found. A huge number of studies dealt with different applications of chlorine substances which are not approved in the European Union and the reduction level did not exceed 3 log10 values. None of the measures was able to totally eradicate Enterobacteriaceae from the broiler carcasses indicating the need to develop intervention measures to prevent contamination with ESBL-producing Enterobacteriaceae and, therefore, the exposure of humans and the further release of antibiotic resistances into the environment.

Occurrence of Campylobacter jejuni and C. coli on broiler carcasses after chilling in southern Brazil

Campylobacter jejuniand C. colihave been associated with gastrointestinal disorders in human beings, due mainly to the consumption of chicken meat. Despite control measures for reducing contamination by these bacteria, the detection of Campylobacter in carcasses after chilling remains high.A total of 105 carcasses were assessed by the horizontal detection method in five federally inspected slaughterhouses in southern Brazil in 2012 and in the first three months of 2013. Campylobacterwas isolated in 37.1% of the carcasses, of which 97.5% contained C. jejuni and 2.5% were infected by C. coli. The rate of positive carcasses across the slaughterhouses ranged from 0 to 71.4%. Determining the occurrence of Campylobacteramong flocks is crucial for estimating the microbial load at specific points along the slaughtering process and for minimizing the risk of contamination of end products by Campylobacter.

Salmonella contamination risk points in broiler carcasses during slaughter line processing

Salmonella is one of the foodborne pathogens most commonly associated with poultry products. The aim of this work was to identify and analyze key sampling points creating risk of Salmonella contamination in a chicken processing plant in Costa Rica and perform a salmonellosis risk analysis. Accordingly, the following examinations were performed: (i) qualitative testing (presence or absence of Salmonella), (ii) quantitative testing (Salmonella CFU counts), and (iii) salmonellosis risk analysis, assuming consumption of contaminated meat from the processing plant selected. Salmonella was isolated in 26% of the carcasses selected, indicating 60% positive in the flocks sampled. The highest Salmonella counts were observed after bleeding (6.1 log CFU per carcass), followed by a gradual decrease during the subsequent control steps. An increase in the percentage of contamination (10 to 40%) was observed during evisceration and spray washing (after evisceration), with Salmonella counts increasing from 3.9 to 5.1 log CFU per carcass. According to the prevalence of Salmonella -contaminated carcasses released to trade (20%), we estimated a risk of 272 cases of salmonellosis per year as a result of the consumption of contaminated chicken. Our study suggests that the processes of evisceration and spray washing represent a risk of Salmonella cross-contamination and/ or recontamination in broilers during slaughter line processing.

Marinade with thyme and orange oils reduces Salmonella Enteritidis and Campylobacter coli on inoculated broiler breast fillets and whole wings

Essential oils have been reported to possess antimicrobial properties and therefore have potential usage as natural antimicrobials in food. In a previous study, thyme orange essential oil combination (TOC) used at the 0.5% level as a dip application on chicken cut-up parts had a significant antibacterial effect against Salmonella and Campylobacter. A study was designed to evaluate the effect of salt-phosphate marinade solution containing 0.5% TOC to 1) reduce Salmonella Enteritidis and Campylobacter coli numbers on broiler breast fillets and whole wings marinated by vacuum tumbling, and 2) reduce cross-contamination of both pathogens between inoculated and uninoculated parts during marination. A total of 52 skinless breast fillets and 52 whole wings were used for the 2 replications. For each replication, each cut-up part was randomly assigned to 1 of 5 groups: treatment 1: uninoculated parts marinated without TOC; treatment 2: inoculated parts marinated without TOC; treatment 3: uninoculated parts marinated with TOC; treatment 4: inoculated parts marinated with TOC; and control: nonmarinated inoculated parts. Samples were dipped in an inoculum containing a mixture of Salmonella Enteritidis and C. coli. The treatment samples were marinated by vacuum tumbling. All samples were immediately evaluated to determine Salmonella Enteritidis and C. coli numbers. Results indicated that TOC at the 0.5% level in the marinade solution applied by vacuum tumbling significantly reduced (P < 0.05) numbers of viable Salmonella Enteritidis by 2.6 and 2.3 log cfu/mL on broiler breast fillets and C. coli by 3.6 and 3.1 log cfu/mL on whole wings. Cross-contamination was observed as the uninoculated chicken parts marinated with inoculated parts were positive. However, the number of bacterial cells recovered from the TOC treated samples were significantly lower (P < 0.05) than the numbers recovered from the untreated samples. Marination with a salt phosphate formulation containing 0.5% TOC successfully reduced Salmonella and Campylobacter numbers on poultry products.

Enteropathogenic Escherichia coli contamination at different stages of the chicken slaughtering process

Enteropathogenic Escherichia coli is a foodborne pathogen that produces potentially fatal infant diarrhea, noticeably in developing countries. The aim of this study was to detect EPEC contamination by PCR at different stages of the chicken slaughtering process. We collected swabs from chicken cloacae and washed carcasses (external and visceral cavity) during the slaughtering process in 3 sampling occasions. Unwashed eviscerated carcasses were also sampled (at the visceral cavity) in the second and third sampling occasions. Enteropathogenic Escherichia coli was detected in 6 to 28% of cloacal samples, 39 and 56% of unwashed eviscerated carcasses, and 4 to 58% of washed carcasses. None of the samples were positive for bfpA, suggesting contamination with atypical EPEC. The detection of EPEC at different stages of the chicken slaughtering process showed that the proportion of contaminated samples remained or even increased during processing. In addition, the high proportion of contaminated carcasses during chicken processing represents a risk for the consumers and a challenge to improve procedures for those working in the sanitary control service.

Genotype comparison of sorbitol-negative Escherichia coli isolates from healthy broiler chickens from different commercial farms

Hybridization on arrays was used to assess the presence of virulence-associated genes and to determine the relatedness of 32 non-O157 sorbitol-negative Escherichia coli isolates from healthy broiler chickens. These isolates were from commercial farms that used feed supplemented with different antimicrobial agents (virginiamycin, bacitracin, salinomycin, narasin, nicarbazin, or diclazuril). For each isolate, fluorescent probes were made from genomic DNA and were hybridized on DNA arrays composed of genes associated with general functions, virulence, iron uptake systems, and DNA repair genes (e.g., mut genes). Hybridization on arrays results showed that isolates from the same farm tended to be clustered but actually represented 18 genetically distinct groups of isolates. Results revealed that some isolates showed similarity to human uropathogenic E. coli or avian pathogenic E. coli. Four avian pathogenic E. coli-like isolates were detected. Another isolate possessed the intimin gene (eaeA) and typical genes of the type 3 secretion system associated with enteropathogenic E. coli and enterohemorrhagic E. coli strains. Genes from a second system (secondary type 3 secretion system) homologous to that found in Salmonella Typhimurium were detected in many isolates. Several of the studied isolates also possessed the aerobactin, salmochelin, and yersiniabactin genes involved in iron acquisition in pathogenic bacteria. Our results clearly suggest that commensal E. coli isolates from chickens are reservoirs of virulence-associated genes and may represent colibacillosis and zoonotic risks.

Advances in enteropathogen control in poultry production

Poultry meat has been associated frequently and consistently with the transmission of enteric pathogens, including Salmonella and Campylobacter. This association has resulted in the development of HACCP-based intervention strategies. These strategies (hurdles) begin with elite breeder flocks and filter down the production pyramid. These hurdles include those already established, such as biosecurity, vaccination, competitive exclusion, pre- and probiotics, feed and water control, and those more experimental, such as bacteriophage or immunoglobulin therapy. The reduction in enteropathogens entering the processing plant, which employs critical control points, further reduce the exposure of consumers to these organisms. The synergistic application of hurdles will result in an environment that is restrictive and detrimental to enteropathogen colonization and contamination.

Evolution of resistance in poultry intestinal Escherichia coli during three commonly used antimicrobial therapeutic treatments in poultry

The resistance rates of intestinal Escherichia coli populations from poultry were determined during treatment and withdrawal period with 3 antimicrobial agents commonly used as therapeutics in poultry medicine. A total of 108 chickens were considered: 18 were treated orally with enrofloxacin, 18 with doxycycline, and 18 with sulfonamides, whereas another 18 chickens were maintained as controls for each antimicrobial group. Fecal samples were taken during the treatment and after the withdrawal period, and E. coli were isolated through Fluorocult media plating. A total of 648 E. coli strains (216 per antimicrobial tested) were isolated and identified though biochemical methods. Minimal inhibitory concentrations to the antimicrobials used were also determined using a broth microdilution method. The resistance rates of intestinal E. coli to all of the antimicrobials tested significantly increased during the course of the therapeutic treatment. In addition, significant differences (P = 0.0136) in resistance rates persisted between the intestinal E. coli of the enrofloxacin-treated and control batches until the end of the withdrawal period, but this difference was not observed for the cases of doxycycline or sulfonamides treatments. Antimicrobial use in poultry medicine seems to select for antimicrobial-resistant strains of pathogenic bacterial species such as E. coli. In some cases, the higher frequencies of resistant strains may persist in the avian intestinal tract until the end of the withdrawal period, when it is legal to use these animals for human consumption.