Submitted to: Foodborne Pathogens and Disease
Publication Type: Peer reviewed journal
Publication Acceptance Date: 8/23/2009
Publication Date: 9/8/2009
Publication URL: http://handle.nal.usda.gov/10113/35007
Citation: Jacob, M., Callaway, T.R., Nagaraja, T. 2009. Dietary interactions and interventions affecting Escherichia coli 0157 colonization and shedding in cattle. Foodborne Pathogens and Disease. 6:785-792. Interpretive Summary: Escherichia coli O157 is a foodborne pathogenic bacteria often found in the gut of cattle, where it poses a threat to human health and food safety. Carcass and food contamination is correlated to the presence of E. coli O157 in cattle manure at the time of slaughter. Thus, if E. coli O157 populations can be reduced, then human illnesses can be reduced. The diet fed to cattle can impact fecal E. coli O157 populations, yet this has been very controversial, and data are not clear as to which factors affect shedding the most. Understanding what factors influence fecal shedding will allow for the development of the best practices in animal production that will ensure food safety and security.
Technical Abstract: Escherichia coli O157 is an important foodborne pathogen affecting human health and the beef cattle industry. Contamination of carcasses at slaughter is correlated to the prevalence of E. coli O157 in cattle feces. Many associations have been made between dietary factors and E. coli O157 prevalence in cattle feces. Pre-harvest interventions, such as diet management, could reduce the fecal prevalence and diminish the impact of this adulterant. Dietary influences, including grain type, processing method, forage quality, and distillers grains, have all been associated with E. coli O157 prevalence. In addition, several plant compounds, including phenolic acids and essential oils, have been proposed as in-feed intervention strategies. The specific mechanisms responsible for increased or decreased E. coli O157 shedding or survival are not known but are often attributed to changes in hindgut ecology induced by diet types. Some interventions may have a direct bacterial effect. Frequently, results of studies are conflicting or not repeatable, which speaks to the complexity of the hindgut ecosystem, variation in animal feed utilization, and variation within feed products. Still, understanding specific mechanisms driven by diet influences responsible for E. coli O157 shedding will aid in the development and implementation of better and practical pre-harvest intervention strategies.