Location: Food and Feed Safety Research
2024 Annual Report
Objectives
Objective 1: Determine factors affecting colonization, maintenance, and dissemination of foodborne pathogens and antimicrobial resistant bacteria in the bovine and swine gastrointestinal tract, lymphatic system and their production and processing environments.
Sub-objective 1.A: Identify and characterize factors affecting the infection, colonization, carriage and dissemination of foodborne pathogens and antimicrobial resistant bacteria within the production environment and the resident and transient populations of arthropods in farm and processing environments.
Sub-objective 1.B: Identify and characterize factors affecting colonization and maintenance of Salmonella in the swine proximal alimentary, distal gastrointestinal tract, and associated lymphatics system.
Sub-objective 1.C: Evaluate factors influencing intestinal mucosal integrity of the distal intestinal tract of feedlot cattle and correlation to Salmonella carriage in peripheral lymph nodes.
Objective 2: Identify, develop, and test interventions, including possible synergies of multiple interventions and GRAS (generally regarded as safe) alternatives, to yield effective technologies to control foodborne pathogens or mitigate their virulence and resistance.
Sub-objective 2.A: Determine best-user practices to achieve effective pathogen control for commercially relevant organic acid mixtures and biocides under the varied applications protocols currently used by industry.
Sub-objective 2.B: Overcome the lipophilic limitations of essential oils by chitosan-encapsulation, use of natural or synthetic higher molecular weight carbohydrate-glycosidic conjugates or co-administration with appropriate emulsifiers.
Sub-objective 2.C: Characterize effects of short chain nitrocompounds on hydrogen ecology, redox homeostasis, pathogen competitiveness and gene expression by zoonotic pathogens and resolve uncertainties pertaining to their safe use in animal agriculture.
Approach
The long-term goal of our project is to develop practical, cost-effective, and environmentally compatible strategies to reduce the prevalence and concentration of foodborne pathogens associated with food-producing animals, thus reducing the risk of transmission of foodborne disease and antimicrobial resistance to the American consumer. To accomplish these goals, we need to better understand ecological and biological factors affecting the ability of foodborne pathogens to colonize particular habitats present in animal agriculture and how we can interrupt their ability to survive and persist in these environments. The overall goals of Objective 1 of this project are to determine factors affecting colonization, maintenance, and dissemination of foodborne pathogens and antimicrobial resistant bacteria in the bovine and swine gastrointestinal tract, lymphatic system, and their production and processing environments. The goals of Objective 2 seek to identify, develop, and test interventions, including possible synergies of multiple interventions and GRAS (generally regarded as safe) alternatives, to yield effective technologies to control foodborne pathogens or mitigate their virulence and resistance and apply this knowledge, as well as existing knowledge, to develop interventions to reduce the colonization, carriage, and ultimately the shedding of pathogenic and antimicrobial resistant bacteria in food-producing animals. Ultimately, results obtained from this research will facilitate the development of sound, science-based microflora management strategies to improve gut health and function by reducing the risk of transmission of foodborne disease and antimicrobial resistance in food-producing animals and their production environment.
Progress Report
Work conducted by this project during FY 2024 made significant progress in achieving the goals of Objective 1; establishing factors affecting colonization, maintenance, and dissemination of foodborne pathogens and antimicrobial resistant bacteria in the bovine and porcine gastrointestinal tract, lymphatic system, and in production environments. The work progressed well, and data are being analyzed. Studies also focused on certain food processing and animal waste management practices, and on prospective monitoring technologies, to develop new information on important contributing factors that contribute to the contamination and dissemination of pathogenic and antimicrobial resistant bacteria in animal produced foods and the production environments. Research under Objective 2 made significant progress in identifying, developing, and testing intervention strategies. The focus of this work is on combinations of approaches that will be additive or possibly synergistic and included interventions involving natural or GRAS (generally recognized as safe) alternatives to conventional antibiotic or pathogen control technologies. The goal is to develop effective technologies and protocols to control foodborne pathogens or mitigate their virulence and resistance. These interventions are being designed to contribute to the efficiency and profitability of animal production; industry partners are collaborating to facilitate implementation of these technologies into commercial production environments. Success in this work will help U.S. farmers and ranchers produce safer and more wholesome meat and dairy products, at lower cost, for the consumer.
Accomplishments
1. Antimicrobial activity of anti-methanogenic compounds. Livestock producers need new technologies to maintain optimal health and well-being in their animals while minimizing the risks of growth and spread of antimicrobial-resistant bacteria to humans or other animals. Where possible, these interventions should contribute to the efficiency and profitability of animal production to avoid passing costs on to consumers. ARS researchers at College Station, Texas, working with university collaborators, evaluated the antimicrobial potential of a selection of potential inhibitors of rumen methane production, a digestive inefficiency that results in the loss of up to 12% of the cow's dietary energy intake and contributes nearly 20% of the United States' total emissions of this potent greenhouse gas. Results demonstrated that the compounds studied (ethyl nitroacetate and lipoic acid), effectively decreased methane-producing activity by rumen microbes by 48 to 98%, and also significantly decreased growth rates of the foodborne pathogenic bacteria, Escherichia coli O157:H7 and Salmonella Typhimurium DT104, by as much as 93%. This accomplishment provides livestock producers with a feed strategy to reduce emissions of the potent greenhouse gas, methane, while also improving the gastrointestinal health of their animals. Ultimately, this technology will help livestock producers provide safer meat and milk for the American consumer in a more environmentally sensitive and sustainable manner.
Review Publications
Dittoe, D.K., Anderson, R.C., Krueger, N.A., Harvey, R.B., Poole, T.L., Crippen, T.L., Callaway, T.R., Ricke, S.C. 2023. Campylobacter jejuni response when inoculated in bovine in vitro fecal microbial consortia incubations in the presence of metabolic inhibitors. Pathogens. 12. Article 1391. https://doi.org/10.3390/pathogens12121391.
Levent, G., Bozic, A., Petrujkic, B.T., Callaway, T.R., Poole, T.L., Crippen, T.L., Harvey, R.B., Ochoa-Garcia, P., Corral-Luna, A., Anderson, R.C., Yeater, K.M. 2023. Assessment of potential anti-methanogenic and antimicrobial activity of ethyl nitroacetate, a-lipoic acid, taurine and l-cysteinesulfinic acid in vitro. Microorganisms. 12(1). Article 34. https://doi.org/10.3390/microorganisms12010034.
Dittoe, D.K., Anderson, R.C., Poole, T.L., Crippen, T.L., Harvey, R.B., Ricke, S.C. 2023. Chlortetracycline concentration impact on Salmonella Typhimurium sustainability in the presence of porcine gastrointestinal tract bacteria maintained in continuous culture. Pathogens. 12. Article 1454. https://doi.org/10.3390/pathogens12121454.
Anderson, R.C., Poole, T.L., Crippen, T.L., Harvey, R.B., Ricke, S.C. 2023. Effect of chemostat turnover rate and select antibiotics on Salmonella Typhimurium in the presence of porcine gastrointestinal tract bacteria. Canadian Journal of Animal Science. 104(1):118–122. https://doi.org/10.1139/cjas-2023-0019.
Dittoe, D.K., Anderson, R.C., Krueger, N.A., Harvey, R.B., Poole, T.L., Crippen, T.L., Callaway, T.R., Rickie, S.C. 2023. Survival of Campylobacter jejuni during in vitro culture with mixed bovine ruminal microorganisms in the presence of methanogen inhibitors. Journal of Environmental Science and Health. 58(12):711-717. https://doi.org/10.1080/03601234.2023.2273754.
Crippen, T.L., Kim, D., Poole, T.L., Swiger, S.L., Anderson, R.C. 2024. The bacterial and archaeal communities of flies, manure, lagoons, and troughs at a working dairy. Frontiers in Microbiology. 14. Article 1327841. https://doi.org/10.3389/fmicb.2023.1327841.
Crippen, T.L., Sullivan, J.P., Anderson, R.C. 2024. Bacterial proximity effects on the transfer of antibiotic resistance genes within the alimentary tract of yellow mealworm larvae. Journal of Economic Entomology. 117(2):417-426. https://doi.org/10.1093/jee/toae019.
Swaggerty, C.L., Siegel, P.B., Honacker, C.F., Kogut, M.H., Anderson, R.C., Ashwell, C.M., Taylor, R.L. 2024. Selection for high and low antibody responses to sheep red blood cells influences cytokine and chemokine expression in chicken peripheral blood leukocytes and splenic tissue. Poultry Science. 103(9). Article 103972. https://doi.org/10.1016/j.psj.2024.103972.