Location: Meat Safety and QualityTitle: Ensuring Escherichia coli possessing colibactin genes (clb) linked to colorectal cancer do not become a food safety problem for beef
Submitted to: Journal of Food Protection
Publication Type: Abstract Only
Publication Acceptance Date: 5/1/2021
Publication Date: 7/18/2023
Citation: Guragain, M., Schmidt, J.W., Kalchayanand, N., Bosilevac, J.M. 2023. Ensuring Escherichia coli possessing colibactin genes (clb) linked to colorectal cancer do not become a food safety problem for beef. Journal of Food Protection. 84(Suppl A): P. 134.
Technical Abstract: Introduction: E. coli carrying colibactin genes (clb) induce mutations that lead to colorectal cancer (CRC). Red meat consumption is arguably associated with CRC. Purpose: To establish the prevalence of clb+ E. coli in beef. Methods: A multiplex-PCR that targeted clbA and clbQ genes was used to screen generic E. coli for Clb genes. The E. coli that were previously isolated and archived at USMARC from 72 nine to ten head lots of cattle-at-harvest (n = 1430); 599 retail ground beef products from six different US cities (n = 1074); and 184 fed cattle (3 lots) at seven stages of beef processing feedlot to cuts (n = 232). Prevalences were compared using Fisher’s exact test. Studies are currently underway to evaluate the efficacy of meat processing interventions on reducing numbers of clb+ E. coli. Results: Overall, 11% of E. coli isolated from cattle-at-harvest carried clb in their genome. Fifty of the 72 lots possessed cattle carrying clb+ E. coli, with the lot-to-lot prevalence ranging from 4.5% to 50%. Among ground beef E. coli, clb was detected in 4.1% (44) isolates that came from 28 ground beef samples. clb+ E. coli were detected in samples from all 6 US cities (1% to 12.5% samples/city) representing 3 geographical regions. Finally, prevalence of clb+ E. coli in the beef processing continuum was established to be extremely low (2/232) and clb+ E. coli were present only in early stages of continuum; feedlot feces (1/36) and harvest hide (1/36). Significance: The prevalence level of 4.1% in finished ground beef suggests that it may act as a vehicle of clb+ E. coli. Identifying efficacious processing interventions that reduce clb+ E. coli can improve beef safety and impact CRC.