1a. Objectives (from AD-416):
Objective 1. Develop reliable and reproducible challenge models with Salmonella and Campylobacter for use in accurately developing, evaluating, and validating processes for reducing pathogen load using various chemical sanitizers. Objective 2. Develop, evaluate, and validate current and novel chemicals, operational protocols, and sampling methodologies used during poultry production and processing of broilers for the reduction and/or control of foodborne pathogens. Sub-objective 2.1. Assess the ability of commercial and novel chemical sanitizers to reduce or eliminate Salmonella, Campylobacter, and Pseudomonas species from inoculated broiler carcasses and parts. Sub-objective 2.2. Examine the effectiveness of chemical sanitizers applied to carcasses before defeathering or before chilling to reduce contamination by Salmonella and Campylobacter carcasses in postchill carcasses. Sub-objective 2.3. Formulate novel microbicidal surfactants from mixtures of medium-chain fatty acids (MCFA) and organic acids (OA) to be used as sanitizers to significantly reduce microbial contamination during poultry processing. Objective 3. Identify and evaluate risk factors in the production, management, transportation, or processing that impact bird/egg contamination with foodborne pathogens and develop intervention strategies to control pathogens in the absence of antibiotics. Sub-objective 3.1. Assess the ability of chemical sanitizers to reduce contamination of inoculated, fertile eggs by Salmonella. Sub-objective 3.2. Identify and evaluate risk factors in the production, management, transportation, or processing that impact broiler contamination with foodborne pathogens and develop intervention strategies to control pathogens in the absence of antibiotics. Objective 4. Determine the extrinsic factors that impact the survival and attachment of microorganisms including evaluating media and growth factors. Develop and validate new improved technologies to isolate and propagate foodborne pathogens. Sub-objective 4.1. Evaluate media and growth factors and use the findings to develop new, improved technologies for the isolation and propagation of Campylobacter. Sub-objective 4.2. Assess accuracy of current laboratory methods in recovering Salmonella from poultry, animal feeds, and dry environmental samples with fermentable substrates available and development of a more efficient pre-enrichment media.
1b. Approach (from AD-416):
Poultry products contaminated by Salmonella and Campylobacter continue to be major sources of human foodborne illnesses. Live poultry are sporadically colonized by these pathogens, and the birds may serve as reservoirs for the bacteria without displaying any signs of illness or declines in performance. Cross contamination of carcasses during processing may spread the bacteria to poultry meat which may cause foodborne infections if the meat is not properly handled. Therefore, the primary goal of our research will be to develop novel interventions that may be used by commercial poultry producers and processors to reduce contamination of poultry by Salmonella, Campylobacter, and indicator microorganisms. Novel chemical sanitizers that may be used during processing to reduce carcass contamination by foodborne pathogens will be formulated or identified. Factors that enhance survival of these pathogens will be identified and used to formulate a novel bacteriological medium that will be utilized in research projects to determine the efficacy of currently available and newly developed interventions. The project outcomes will result in additional control measures that will reduce the levels of Salmonella and Campylobacter in broiler flocks and reduce contamination of processed carcasses by these pathogens. These outcomes will enable the poultry industry to achieve Food Safety Inspection Service (FSIS) performance standard goals and to reduce the number of cases of human foodborne illness associated with contaminated poultry products. Research goals will be achieved by utilizing an interdisciplinary approach that incorporates knowledge and skills of the scientists and other scientists who possess skills and resources required to successfully compete this project.
3. Progress Report:
Also, the effect of acidic conditions on the injury and death of Salmonella was determined. Additionally, researchers collaborated with the Food Safety Inspection Service (FSIS) to develop a neutralizing solution for use in Salmonella verification testing in commercial poultry processing facilities. The neutralizer is now being utilized in testing in commercial processing facilities. Under Objective 3, the potential impact of adding cetylpyridinium chloride (CPC) as a preharvest Salmonella intervention during preslaughter feed withdrawal was evaluated and water and feed consumption monitored. Broilers were challenged with Salmonella and provided water containing CPC or tap water. After feed withdrawal or full-fed there were no significant differences in Salmonella recovery from the crop or ceca between the CPC treatment and control groups, or among the feed and water withdrawal time periods. Trials revealed that water usage and feed consumption of broilers provided varied CPC concentrations was decreased compared to the control value and that the addition of hydrogen peroxide did not improve water or feed consumption. Additionally, under Objective 3, sampling commercial broiler flocks the week prior, the day prior, and the day of catching for transport to the processing plant revealed that initial cecal sampling results fail to predict Salmonella prevalence following feed withdrawal. Respiratory tracts are not significantly increased in contaminated with Salmonella, aerobic, or Enterobacter bacteria following raising the feeders and water lines and catching one truck load of broilers. Under Objective 4, studies were conducted to formulate a novel selective, bacteriological medium for growth of Campylobacter in containers incubated aerobically.
1. Novel selective, bacteriological medium formulated to support growth of Campylobacter. ARS researchers in Athens, Georgia, formulated a new, selective bacterial medium that allows scientists and technicians to grow Campylobacter in containers incubated aerobically. Campylobacter is a major, bacterial foodborne pathogen associated with the consumption of contaminated poultry products and other foods. However, research on the bacterium is limited because the pathogen must be grown under artificial atmospheres on media supplemented with blood. The new medium does not require the utilization of artificial atmospheres or blood. Furthermore, the addition of selective agents to the medium enables researchers to isolate the bacterium from environmental samples that contain other microorganisms. The novel medium will simplify procedures and reduce costs required to grow the pathogen; thereby, increasing the number of laboratories able to conduct research on this bacterium.
2. Isolation and identification of amylase-producing, endospore-forming bacteria for use in defined probiotic cultures. ARS researchers in Athens, Georgia, isolated amylase-producing, endospore-forming bacteria from the intestinal tract of commercially processed broiler carcasses. Probiotics are cultures of beneficial bacteria that are provided to live poultry to reduce the colonization of the birds by foodborne pathogens, such as Salmonella. Including bacteria that produce the enzyme, amylase, in probiotic cultures might improve the efficacy of these products because amylase can breakdown starch in poultry feed to produce simple sugars that can be used by other beneficial bacteria. The amylase-producing bacteria were identified because regulatory agencies only approve the use of probiotics of known bacterial composition. More effective probiotics will reduce the number of human pathogens carried by live poultry; thereby, reducing the number of illnesses associated with the consumption of contaminated poultry.
3. Development of neutralizing Buffered Peptone Water (nBPW) to inactivate chemical sanitizers in Salmonella verification studies. ARS researchers in Athens, Georgia, collaborated with the Food Safety Inspection Service (FSIS) to develop a neutralization solution (nBPW) for use by commercial poultry processors in Salmonella verification testing. Commercial poultry processors use chemical sanitizers during processing to reduce contamination of carcasses by human foodborne pathogens. However, if traces of these sanitizers are carried-over into testing samples used to determine contamination of poultry carcasses and parts by Salmonella, the results of these tests may be inaccurate. The utilization of the nBPW improves the accuracy of Salmonella verification testing by inactivating trace-amounts of the sanitizers in the test samples. On July 1, 2016, the FSIS informed inspectors in commercial poultry processing facilities that nBPW should be used in all verification testing, and the FSIS is currently seeking a commercial vendor to produce nBPW. The utilization of nBPW will improve the accuracy of verification testing and will provide regulatory agencies and food safety researchers with reliable data to develop methods to reduce contamination of processed poultry by foodborne pathogens.
4. Broiler cecal and respiratory tracks Salmonella. ARS researchers in Athens, Georgia, sampled commercial broilers the week prior or the day prior to catching for transport to the processing plant and revealed that initial cecal sampling results fail to accurately predict Salmonella prevalence following feed withdrawal. Respiratory tracts are not significantly contaminated with Salmonella, aerobic, or Enterobacter bacteria following house preparation and catching. These results further complicate the practical implication of logistic slaughter by attempting to process negative and false negative flocks first each processing day.
5. Electrically stunning shackled broilers. ARS researchers in Athens, Georgia, in 2016 demonstrated that electrically stunning shackled broilers using a combination of pulsed DC (salt-water bath for 10 seconds) followed by the application of AC (contact plate for 5 seconds) confirmed 100% efficacy in induction of a non-recoverable stun-to-death. In 2017 ARS researchers in Athens, Georgia, sampled and confirmed that there were no significant differences for broiler whole carcasses (hemorrhages, red wing tips, broken clavicles) and breast or leg meat quality characteristics (meat pH, cook loss, redness and yellowness color values, and instrumental tenderness) between control and the stun-to-death treatment groups (DC+AC combination stunning). These data indicate that these stunning parameters combining DC and AC stunning should be viable protocols when a stun-to-death is desired. Commercial processing plants can utilize this combined DC+AC stun for any customers that may require assurance of an irreversible electrical stun at slaughter.
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