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An Integrated Approach to Evaluating Human Exposure to Antimicrobial Resistance Through Consumption of Beef and Lettuce

Yangjunna Zhang, University of Nebraska - Lincoln


Antimicrobial-resistant bacteria (ARB) persisting in the beef cattle processing and post-processing continuum can be transferred to finished meat products, and ultimately to consumers. In addition, livestock production systems can spread ARB to their associated environments through vehicles such as manure, soil, runoff, and air, and finally contaminate production of leafy greens. However, the potential transfer routes of ARB from livestock production operations to humans have not been fully characterized. The goal of this integrated research is to evaluate the human exposure to ARB through the consumption of one serving beef or leafy greens related to the livestock production environment, and to develop effective mitigation strategies that could be easily practiced in food safety management to control human exposure to ARB via the consumption route. With quantitative exposure assessment modelling, the transmission of ARB was quantified along the beef and fresh-cut leafy greens farm-to-fork continuum. Critical input variables were fit to stochastic distributions by meta-analysis using observed data from primary studies included by systematic review. Results showed that consumption of fresh-cut leafy greens meals might be more likely to expose consumers to ARB, compared to eating of beef; ground beef was estimated to carry more organisms than non-intact and intact beef cuts. Restriction of antimicrobial use in beef cattle production system, or irrigation of field leafy greens with water distal to livestock operations, might be associated with a reduction in ARB exposure, but the magnitude was found to be limited. Although sectors along the supply chain, i.e., producer, processor, retailer, and consumer, were all important for controlling human exposure to ARB, it was worthwhile to focus on consumer-related practices. Besides good hygiene practices at home, integration of sufficient cooking time and temperature for beef, and proper storage time and temperature at retail and home for fresh-cut leafy greens, were of more importance to control the consumers’ ARB exposure through beef consumption.

Subject Area

Food Science|Microbiology

Recommended Citation

Zhang, Yangjunna, "An Integrated Approach to Evaluating Human Exposure to Antimicrobial Resistance Through Consumption of Beef and Lettuce" (2020). ETD collection for University of Nebraska-Lincoln. AAI28085931.