A comparative quantitative assessment of human exposure to various antimicrobial-resistant bacteria among U.S. Ground beef consumers

Consumption of animal-derived meat products is suspected as an important exposure route to antimicrobial resistance, as the presence of antimicrobial-resistant bacteria (ARB) along the beef supply chain is well documented. A retail-to-fork quantitative exposure assessment was established to compare consumers’ exposure to various ARB due to the consumption of ground beef with and without “raised without antibiotics” claims and to inform potential exposure mitigation strategies related to consumer practices. The microbial agents evaluated included Escherichia coli, tetracycline-resistant (TET^r) E. coli, third-generation cephalosporin-resistant E. coli, Salmonella enterica, TET^r S. enterica, third-generation cephalosporin-resistant S. enterica, nalidixic acid–resistant S. enterica, Enterococcus spp., TET^r Enterococcus spp., erythromycin-resistant Enterococcus spp., Staphylococcus aureus, and methicillin-resistant S. aureus. The final model outputs were the probability of exposure to at least 0 to 6 log CFU microorganisms per serving of ground beef at the time of consumption. It was estimated that tetracycline resistance was more prevalent in ground beef compared with other types of resistance, among which the predicted average probability of ingesting TET^r Enterococcus was highest (6.2% of ingesting at least 0 log CFU per serving), followed by TET^r E. coli (3.1%) and TET^r Salmonella (0.0001%), given common product purchase preferences and preparation behaviors among beef consumers in the United States. The effectiveness of consumer-related interventions was estimated by simulating the differences in exposure as a result of changes in consumer practices in purchasing, handling, and preparing ground beef. The results indicated that proper use of recommended safe cooking and food preparation practices mitigates ARB exposure more effectively than choosing raised without antibiotics compared with conventional beef.