New Techniques for Ante-Mortem Control of Pathogens in Broilers

NON-TECHNICAL SUMMARY: Food-borne illness associated with exposure to poultry pathogens is a significant problem in the U.S. Poultry carcass contamination can result during animal processing because of the presence of human illness-causing bacteria in the digestive tract at the time of slaughter. The purpose of this technology development and demonstration project is to integrate a safe, organic disinfectant into poultry drinking water to kill harmful bacteria in the digestive tract of poultry just prior to slaughter. In earlier studies, the new chemical additive supplemented in the drinking water reulted in a significant reduction of Salmonella in the upper digestive tract. Newly planned activities will expand the scope of the pre-slaughter testing, including development of a pilot chemical mixing and delivery system for testing at a commercial facility followed by sampling at the slaughterhouse. We will also develop a comprehensive data package to support a New Animal Drug Application for approval by the FDA. This new product has a high potential for low-cost manufacture and economical sale to the poultry industry.

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APPROACH: The goal of the Phase II project is two-fold: (i) to resolve key technical issues related to the biocidal activity and safe, adequate consumption of the treated drinking water during various time points during poultry growout; and (ii) to design, fabricate, and field test a pilot scale system for plumbing directly into a commercial nipple watering system followed by post slaughter microbiological evaluation. This will be accomplished by small scale (25 birds per group), parametric testing of biocide concentration, stability, palatability, and exposure duration and the subsequent effect pathogen destruciton efficiency. After optimization, a system will be constructed that will be easily integrated into conventional water medication systems (nipple-style drinkers).

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PROGRESS: 2000/09 TO 2005/05<BR>
Gastrointestinal pathogens are the principle cause of human foodborne infections in many countries. There is evidence that poultry serves as a significant reservoir for Salmonella in the food supply. Improvements in processing procedures and sanitary methods within processing plants have allowed for general microbiological improvements in overall carcass quality through the initial stages of processing. However, the intestinal contents of some chickens may harbor large populations of Salmonella, and cross contamination during processing has been observed. The incidence of Salmonella on broiler carcasses has been shown to increase with successive stages of processing, possibly due to Salmonella's ability to firmly attach to poultry tissue. Therefore, to significantly reduce the level of exposure of consumers to contamination on processed birds, pathogen free or near-pathogen free birds must be delivered to the processing plant (Bailey, 1993). Much research has focused on cecal and intestinal content contamination as the primary source of Salmonella within chicken. However, recent reports have shown the crop may potentially serve as an important source of Salmonella contamination on broiler carcasses within some processing plants. A higher incidence of Salmonella in crops than in ceca has been reported, along with a higher incidence of ruptured crops than ruptured ceca during commercial evisceration. In addition, colonization of the crop by Salmonella can increase as chickens near processing age. Consequently, the crop is now implicated as an important cause of broiler carcass contamination. This is the Phase II final report outlining progressive accomplishments toward development, fabrication, evaluation and commercialization of a new pathogen decontamination technology for the live poultry production industry. This technical approach involves treating the crops (upper GI tract) of broilers, which become contaminated with human pathogens (i.e., Salmonella, Campylobacter) during growout, particularly via ingestion of litter and feces during feed withdrawal. Contaminated broiler crops were treated using perlactic acid solutions administered via the nipple style drinking water lines followed by microbiological analysis to determine pathogen destruction. In addition to perlactic acid, other disinfectants were also investigated for use in this capacity, including solid dipercarboxylic acids.
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IMPACT: 2000/09 TO 2005/05<BR>
In a laboratory setting (using clean drinking water lines), perlactic acid (PLA) is a potent oral antimicrobial, reducing Salmonella by >2.5 log10 in the crops of infected birds. After mixing the concentrate and diluting the perlactic acid to the appropriate use concentration, a window between 8 and 28 hours yields the highest concentration of perlactic acid. Although adding a greater percentage of hydrogen peroxide yields a higher concentration of PLA initially, the greater percentage does not sustain the reaction, and degradation of PLA occurs at a much more rapid rate than with a lower concentration. The lower concentrations of peroxide are also in compliance with DOT shipping restrictions. The pH of water used to dilute the PLA has a negligible effect on its rate of degradation. In field demonstration studies analyzing the efficacy of PLA as a crop disinfectant delivered via actual commercial grower house drinking water lines, PLA showed no appreciable kills of either Salmonella or Campylobacter in the crops of infected birds. This unexpected result most likely occurred due to a lack of PLA actually reaching the birds, and instead being consumed by the organic material, biofilm, and sludge present in the commercial drinking lines. Preliminary screenings indicate that dipercarboxylic acid powders could prove to be a viable alternative to liquid perlactic acid as a crop disinfectant for Salmonella and Campylobacter species. It is safer to administer (no mixing of chemicals) and has more oxidant power per mole than perlactic acid.