Bacteria recovery from genetically feathered and featherless broiler carcasses after immersion chilling

The Prevalence of Salmonella and Campylobacter on Broiler Meat at Different Stages of Commercial Poultry Processing

In poultry processing, Salmonella and Campylobacter contaminations are major food safety concerns. Peracetic acid (PAA) is an antimicrobial commonly used in commercial poultry processing to reduce pathogen prevalence so as to meet the USDA-FSIS performance standards. The objective of this study was to determine the prevalence of Salmonella and Campylobacter on broiler meat in various steps of commercial poultry processing in plants that use PAA. Post-pick, pre-chill, post-chill, and drumstick chicken samples were collected from three processing plants and mechanically deboned meat (MDM) was collected from two of the three plants. Each plant was sampled thrice, and 10 samples were collected from each processing step during each visit. Among the 420 samples, 79 were contaminated with Salmonella and 155 were contaminated with Campylobacter. Salmonella and Campylobacter contamination on the post-pick samples averaged 32.2%. Significant reductions in Salmonella and Campylobacter were observed in pre-chill to post-chill samples, where the prevalence was reduced from 34% and 64.4% to nondetectable limits and 1.1%, respectively (p < 0.001). Salmonella and Campylobacter remained undetectable on the drumstick samples in all three processing plants. However, the prevalence of Salmonella and Campylobacter on MDM was similar to the post-pick prevalence, which suggests substantial cross-contamination from post-chill to MDM.

Inhibitory effect of ethanol and thiamine dilaurylsulfate against loosely, intermediately, and tightly attached mesophilic aerobic bacteria, coliforms, and Salmonella Typhimurium in chicken skin

The effects of 3 ethanol levels (30, 50, and 70%) with and without thiamine dilaurylsulfate (TDS; 1,000 ppm) were evaluated for the reduction of natural mesophilic aerobic bacteria (MAB), coliforms, and inoculated Salmonella Typhimurium (S. Typhimurium) in chicken skin. The chicken skin was inoculated with a 7 log cfu/mL suspension of S. Typhimurium. Loosely, intermediately, and tightly attached cells were recovered from chicken skin through shaking at 200 rpm for 5 min, stomaching for 1 min, and blending for 1 min, respectively. Increasing the ethanol concentration reduced the number of MAB, coliforms, and S. Typhimurium on the chicken skin, whereas TDS treatment without ethanol was not effective. Intermediately and tightly attached microorganisms (total MAB, coliforms, and S. Typhimurium) were more resistant to chemical disinfectants than loosely attached microorganisms. The combination of 70% ethanol with TDS was most effective than the combination of TDS with lower concentrations of ethanol in reducing populations of loosely, intermediately, and tightly attached MAB (by 1.88 log cfu/g, 1.21 log cfu/g, and 0.84 log cfu/g, respectively), coliforms (by 1.14 log cfu/g, 1.04 log cfu/g, and 0.67 log cfu/g, respectively), and S. Typhimurium (by 1.62 log cfu/g, 1.72 log cfu/g, and 1.27 log cfu/g, respectively). However, the chicken skin treated with higher concentrations of ethanol was tougher (P < 0.05) and more yellow and less red (P < 0.05) than that treated with lower concentrations of ethanol or with water (control). On the other hand, a combination of 30% ethanol and TDS yielded the best results, showing the reduction greater than 0.5 log cfu/g in S. Typhimurium, with no negative effect on chicken skin color or texture. Thus, a combination of 30% ethanol and TDS appears to be the optimal treatment for reducing microbial contamination of skin-on chicken products to enhance poultry safety without decreasing food quality, and this treatment could be applied in the poultry industry.

Impact of ethanol and ultrasound treatment on mesophilic aerobic bacteria, coliforms, and Salmonella Typhimurium on chicken skin

The present study evaluated the efficacy of ethanol treatment (0, 30, 50, or 70%) alone or in combination with ultrasound (37 kHz, 380 W) for the reduction of natural indigenous mesophilic aerobic bacteria (MAB), coliforms, and inoculated Salmonella Typhimurium on chicken skin. Bacterial cells with loose, intermediate, or tight attachment to chicken skin were recovered by shaking in an incubator (200 rpm) for 5 min, stomaching for 1 min, or blending for 1 min, respectively. Chicken skins were inoculated with a suspension (7 log CFU/mL) of S. Typhimurium. Ethanol reduced the number of MAB, coliforms, and S. Typhimurium on the chicken skin in a concentration-dependent manner, whereas ultrasound treatment without ethanol was ineffective. A combination of 70% ethanol with ultrasound treatment was the most effective in reducing S. Typhimurium populations with loose, intermediate, and tight attachment (reduction by 2.86 log CFU/g, 2.49 log CFU/g, and 1.63 log CFU/g, respectively). However, chicken skin treated with 50% ethanol alone or with a combination of >50% ethanol and ultrasound showed significant changes in Hunter color values (a* and b*) and texture (shear force) (P > 0.05). On the other hand, a combination of 30% ethanol and ultrasound yielded the best results, leading to a reduction of S. Typhimurium by a >1.0 log CFU/g, but did not alter the color or texture of chicken skin. Thus, a combination of 30% ethanol and ultrasound appears to be the optimum treatment for reduction of microbial contamination in production and distribution of skin-on chicken products, and enhance poultry safety without decreasing food quality.

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.

The effect of high-level chlorine carcass drench on the recovery of Salmonella and enumeration of bacteria from broiler carcasses

A study was conducted to determine the bacteriological effect of exposing processed broiler carcasses to a high (10-fold increase) concentration chlorinated drench. During each of 6 replicate trials, eviscerated prechill carcasses were obtained from a commercial processing plant and chlorine-treated carcasses were subjected to a 1-min drench in 500 mL of a 500 mg/kg chlorine solution (sodium hypochlorite). Water-drenched carcasses were treated the same way except water was used in place of chlorinated water drench. Control carcasses were not drenched. All carcasses were then subjected to a whole carcass rinse (WCR) in 450 mL of buffered peptone water, from which 50 mL of the rinsate was removed for enumeration of total aerobic bacteria (APC), Escherichia coli, and total coliforms (TC). The entire carcass was then incubated 24 h at 37°C (whole carcass enrichment, WCE) for recovery of Salmonella. Levels of bacteria recovered from WCR were lower by 0.6 log10 cfu/mL for APC, 0.8 for E. coli, and 0.9 for TC when carcasses were drenched with water compared with undrenched control levels. Similarly, the levels of bacteria recovered from WCR were further lower by 1.0 log10 cfu/mL for APC, 0.5 for E. coli, and 0.5 for TC, when carcasses were drenched with 500 mg/kg of chlorine compared with water. However, there was no significant difference (P > 0.05) in prevalence of Salmonella among the treatments (29% positive for control, 26% positive for water, 38% positive for chlorinated). These results indicate that drenching eviscerated carcasses with water or chlorinated water at 500 mg/kg significantly, but minimally, reduces the numbers of APC, E. coli, and TC bacteria recovered compared with undrenched carcasses. However, neither drenching carcasses with water or high chlorine had an effect on the prevalence of Salmonella that remain with the carcass as determined by WCE. The results of this study confirms the importance of maintaining and replenishing free chlorine for optimal antimicrobial activity, because chlorine at 500 mg/kg was rapidly used within 1 min of exposure to the carcass to <10 mg/kg.

The evaluation of combined chemical and physical treatments on the reduction of resident microorganisms and Salmonella Typhimurium attached to chicken skin

This study was conducted to evaluate the efficacy of sodium hypochlorite (NaOCl, 0-200 mg/kg), thiamine dilauryl sulfate (TDS, 1,000 mg/kg), and ultrasound (37 kHz, 380 W) on reducing Salmonella Typhimurim, mesophilic aerobic bacteria (MAB), and coliforms on chicken skin. Chemical and physical treatments were applied for 5 min either singly or jointly, and Salmonella previously inoculated on chicken skin were quantitatively assessed using brilliant green agar, and the populations of MAB and coliforms in the native flora were enumerated using plate count agar and violet red bile agar, respectively. In the evaluation of bacterial attachment/detachment, chicken skin was quantitatively assessed for loosely, intermediately, and tightly attached bacteria. The treatment effects on bacteria detachment were also visualized using field emission scanning electron microscopy. In addition, color and textural properties of the skin after treatments were evaluated using a color difference meter and texture analyzer. Antimicrobial activity of NaOCl increased as the NaOCl concentration was increased, especially for loosely attached cells. The combination of 200 mg/kg NaOCl and ultrasound (NaOCl/ultrasound) significant reduced loosely, intermediately, and tightly attached bacteria populations by 0.75 to 0.47, 0.43 to 0.41, and 0.83 to 0.54 log cfu/g for MAB, coliforms, and Salmonella Typhimurium, respectively. However, the combination of NaOCl and TDS (NaOCl/TDS) did not sufficiently reduce those cells on chicken skins, except for loosely attached MAB and coliforms. The NaOCl/ultrasound combination produced a higher reduction in numbers of inoculated and native bacteria flora than any single application, with no negative effect on skin color or texture. Generally, the loosely attached bacteria were less resistant to the chemical and physical treatments than the intermediately and tightly attached bacteria in chicken skin, presumably due to their location in deeper skin layer and crevices. Further research is needed to investigate how the intermediately and tightly attached microorganisms can be effectively eliminated from chicken skin.

Effect of cooled and chlorinated chiller water on Campylobacter and coliform counts on broiler carcasses during chilling at a middle-size poultry processing plant

To evaluate the effect of cooled and chlorinated chill water for Campylobacter and coliforms at a middle-size processing plant which was considered to be difficult for eliminate pathogenic bacteria on carcasses, following three conditions were examined; keeping temperature at < 20, < 10 and < 10°C, and chlorine concentration at < 50, < 50 and 50 to 70 ppm during processing in experiment 1, 2 and 3 respectively. Fifteen prechill and 15 postchill carcasses were examined in each experiment. In lower temperature of experiment 2, decreasing rate (%) of coliforms was significantly higher (P<0.01) than that in experiment 1. In higher chlorination of experiment 3, no Campylobacter was detected from all postchill carcasses.

Reducing the Carriage of Foodborne Pathogens in Livestock and Poultry

Several foodborne pathogens, including Salmonella species and campylobacters, are common contaminants in poultry and livestock. Typically, these pathogens are carried in the animal's intestinal tract asymptomatically; however, they can be shed in feces in large populations and be transmitted by other vectors from feces to animals, produce, or humans. A wide array of interventions has been developed to reduce the carriage of foodborne pathogens in poultry and livestock, including genetic selection of animals resistant to colonization, treatments to prevent vertical transmission of enteric pathogens, sanitation practices to prevent contamination on the farm and during transportation, elimination of pathogens from feed and water, feed and water additives that create an adverse environment for colonization by the pathogen, and biological treatments that directly or indirectly inactivate the pathogen within the host. To successfully reduce the carriage of foodborne pathogens, it is likely that a combination of intervention strategies will be required.

Campylobacter in poultry: filling an ecological niche

Epidemiological studies indicate that Campylobacter species may be responsible for the majority of cases of sporadic gastroenteritis in humans. These studies also suggest that poultry may be one of the most common sources of the bacteria for humans. Campylobacter and related genera in the family Campylobacteraceae are oral and intestinal commensals of vertebrates and some nonvertebrates, a characteristic that complicates rational approaches to controlling Campylobacter contamination of poultry. This review will discuss the phylogeny, genomics, and physiology of campylobacters with the intention of revealing how these organisms have evolved to fill their intestinal ecological niche in poultry and how their physiology must be understood in order to enact effective control strategies.