Location: Food and Feed Safety Research
2021 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
This is a new project that replaced the bridging project 3091-32000-036-00D. This new project and the precursor bridging project made significant progress in Fiscal Year (FY) 2021 in achieving the goals of Objective 1. Work to determine 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 progressed well and data are being analyzed. Project work identified a previously unrecognized microbial vector potentially contributing to antimicrobial resistance transfer. Additionally, research focused on Objective 2 made significant progress in identifying, developing, and testing intervention strategies. The focus of the work is on combinations of approaches that will be additive or possibly synergistic and includes the study of interventions involving GRAS (generally recognized as safe) alternatives to conventional antibiotics. 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 for the consumer.
Accomplishments
1. Control of microbes in animal feeds to preserve nutritive value and enhance food safety. Spoilage of fermented feedstuffs during the feed-out phase can result in nutrient loss, and also enrichment of pathogenic as well as antimicrobial resistant microbes. Such pathogens put livestock at risk of infection and subsequent contamination of meat and dairy products reaching the consumer. ARS researchers at College Station, Texas, working with university cooperators, developed and tested novel formulations of naturally occurring medium chain fatty acids, and a short-chain nitro compound, 2-nitropropanol, as potential silage treatments. These formulations exhibited potent antimicrobial activity against the tested pathogenic and antimicrobial resistant bacteria, and also against spoilage-causing yeasts and molds when applied as treatments to air-exposed silage. The formulations were found to be potent inhibitors of methane production in cattle, a beneficial effect that may help reduce economic and environmental costs of this potent greenhouse gas. This accomplishment is important because it has identified new approaches to control problematic microbes associated with livestock production, ensure maintenance of feedstuff nutritional value, and enhance environmental quality by reducing methane generation by cattle and other food-producing animals.
