1a. Objectives (from AD-416)
1. Develop, evaluate, and validate alternatives to current antimicrobials and sanitizers for processing poultry carcasses that meet national and international food safety standards. Specifically, alternatives to chlorine and chlorine dioxide, such as GRAS surfactants, ozone, acidified sodium chloride, and peroxyacids should be examined. 2. Characterize and evaluate poultry processing conditions associated with processed broiler carcasses that are heavily contaminated by Salmonella. This objective will include determining microbial recovery/extraction rates for poultry rinse sampling and examining survival characteristics for Salmonella serotypes that survive processing operations. Sampling should include whole carcasses that are high shedders, and mechanically-separated poultry parts. 3. Conduct studies on extrinsic factors that influence the survival and attachment of pathogenic, spoilage, and indicator microorganisms recovered from commercial poultry processing operations. These include water activity, pH, ozone, metal chelators, and organic acids. 4. Collaborate with the QSARU at Athens to develop emerging technologies for process control and correlate molecular and cultural analysis of microbial communities in poultry with process control and pathogen contamination.
1b. Approach (from AD-416)
Technologies will be developed that can be utilized by commercial processors to reduce microbial contamination associated with poultry processing. Formulations for novel sanitizers will be developed, and improved techniques utilizing sanitizers already approved for commercial use in processing will be designed. Surfactant based sanitizers used alone or in combination with non-chlorine based sanitizers will be examined as alternatives to chlorine and chlorine dioxide for decreasing microbial contamination of poultry. Additionally, poultry processing conditions associated with broiler carcasses heavily contaminated by Salmonella will be evaluated and characterized. Cross contamination during processing will be examined by studying the role of these heavily contaminated carcasses in the spread of Salmonella during processing. Furthermore, factors that influence survival and attachment of pathogenic, spoilage, and indicator microorganisms on poultry skin will be examined. Microorganisms on poultry skin will be examined utilizing Benchtop scanning electron microscopy (SEM) with SEM software and with standard microbiological methods. Finally, in collaboration with the Quality Assessment Research Unit (QARU), correlations between molecular and cultural analysis of microbial communities on poultry skin will be examined and emerging technologies for process control will be developed. Technology will be designed for use in the rapid detection and identification of pathogenic bacteria associated with poultry processing and for the characterization of microbial biofilms on broiler skin. All research goals will be achieved through an interdisciplinary team approach utilizing knowledge and skills of Unit scientists and other scientists who possess unique skills and resources that will aid in the successful completion of this project.
3. Progress Report
Although several chemical sanitizers are available for use by poultry processors, contaminated poultry meat continues to be cited as a major source of human foodborne illnesses. Therefore, research was completed on formulations for novel sanitizers that can be used to reduce microbial contamination of processed poultry. Solutions of alkaline salts of fatty acids that possess antimicrobial activity were examined for use in formulations of an effective poultry processing sanitizer. Experiments were conducted to determine the effect of pH on the antibacterial activity of mixtures prepared by dissolving caproic, caprylic, capric, lauric, or myristic acids in solutions of potassium hydroxide (KOH). The high pH of these solutions was produced by KOH, and citric acid was used to reduce the pH of the solutions. Results of experiments indicated that there was little difference in the antibacterial activity of fatty acid mixtures between pH 9.5 to 12.5; however, antibacterial activity of the solutions increased at pH 13.5 or higher. Findings from these experiments demonstrated that the final pH of sanitizers made from fatty acids may influence the ability of the sanitizer to reduce microbial contamination of processed poultry. Pulsed-field gel electrophoresis (PFGE) and repetitive extragenic palindromic sequence-polymerase chain reaction (REP-PCR) were used to identify Salmonella Enteritidis isolates from broiler carcasses and water samples collected in commercial poultry processing facilities. The relatedness of the Salmonella isolates was also determined. These isolates were added to the collection of previously identified Salmonella isolates obtained from commercial poultry processing facilities. Project replaced Project #6612-41420-013-00D and Bridging Project #6612-41420-016-00D.
1. Effect of pH on the antibacterial activity of alkaline salts of fatty acid. In vitro experiments were conducted to determine the effect of pH on the antibacterial activity of caproic, caprylic, capric, lauric, and myristic acids towards bacteria associated with poultry processing. Experiments were conducted to determine the effect of pH on the antibacterial activity of mixtures prepared by dissolving caproic, caprylic, capric, lauric, or myristic acids in solutions of potassium hydroxide (KOH). The high pH of these solutions was produced by KOH, and citric acid was used to reduce the pH of the solutions. Results of experiments indicated that there was little difference in the antibacterial activity of fatty acid mixtures between pH 9.5 to 12.5. However, antibacterial activity of the solutions increased at pH 13.5 or higher. These experiments demonstrated the importance of the pH of formulations. Research will provide data to researchers and commercial processing facilities on the importance of monitoring pH when utilizing these sanitizers to kill harmful microorganisms associated with poultry processing.
Hannah, J.F., Cason Jr, J.A., Richardson, L.J., Cox Jr, N.A., Hinton Jr, A., Buhr, R.J., Smith, D.P. 2011. Effect of stomaching on numbers of bacteria recovered from chicken skin. Poultry Science. 90:491-493.