Submitted to: Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 10/18/2007
Publication Date: 12/3/2007
Citation: Anderson, R.C., Ricke, S., Callaway, T.R., Edrington, T.S., Harvey, R.B., Krueger, N.A., Jung, Y., Nisbet, D.J. 2007. Pre-harvest food-safety; strategies to reduce the burden of enterohemorrhagic Escherichia coli and Salmonella in beef cattle on the farm. In: Proceedings of the 1st Simposium Internacional de Ganado Bovino Productor de Carne, May 7-9, 2008, Zacatecas, Mexico. 2008 CDROM.
Interpretive Summary: Foodborne disease infections affect greater than 76,000,000 people in the United States every year. A bacterial pathogen known as Salmonella causes about 1.3 million of these illnesses whereas a pathogen known as Escherichia coli O157 causes more than 62,000 of these infections. Costs associated with foodborne illness caused by these bacteria exceed $2.4 billion for Salmonella and $445 million for E. coli O157. Considerable work has been and continues to be conducted by government agencies around the world and by all involved in livestock and food production to ensure food is safe for human consumption. Food producers recognize that combining on-farm and food processing measures to achieve multiple pathogen control interventions is the most effective way to minimize contamination of foods. Most cattle herds in the U.S. contain at least some cattle colonized by E. coli O157:H7 although the number of animals within each herd can vary considerably. Salmonella is found in about 10% of feedlot cattle and in about 20% of dairy cattle. Within the farm environment, animal waste, feed, drinking water, house flies, and animal-to-animal contact are considered to play major roles in the spread of these bacteria between animals. Results from experimental studies have shown that feed additives containing chemicals known as chlorate or short chain nitrocompounds may be useful in the controlling these bacteria on the farm. Neither of these technologies has so far been approved by the FDA, and thus they are not able to be used by farmers yet. Preparations of beneficial lactic acid bacteria, such as those found in yogurt and cheeses, have been reported to reduce E. coli O157 in cattle when fed as a feed additive, and they are currently being used by some farmers. Vaccines likewise have been reported to reduce shedding of E. coli O157:H7 by cattle but their use is not yet common. This review, which summarizes information pertaining to the natural cycle of pathogenic E. coli, Salmonella infection in cattle, and current and pending methods for controlling these bacteria, will help scientists and producers make judgements on how to best continue development and implementation of strategies to produce safe beef for the American consumer.
Technical Abstract: Foodborne disease infections effect greater than 76,000,000 people in the United States annually. Salmonella cause an estimated 1.3 million human illnesses whereas Escherichia coli O157 and non-O157 shiga toxin-producing E. coli are estimated to cause more than 62,000 and 31,000 cases of foodborne illness annually. Costs associated with foodborne illness caused by these bacteria exceed $2.4 billion for Salmonella and $445,000,000 for E. coli O157. Considerable effort has been and continues to be expended by government agencies around the world and by all involved in livestock and food production to ensure food is safe for human consumption. Food producers recognize that applying pre-harvest interventions with post harvest technologies for a “multi-hurdle” approach is the most effective way to minimize contamination of foods. The United States Department of Agriculture’s Food Safety Inspection Service identified the “Development of improved on-farm, feedlot, and antemortem interventions for reducing the incidence and levels of pathogens in raw products” as one of their research priorities. Most, if not all, cattle herds in the U.S. contain at least some cattle colonized by E. coli O157:H7 although prevalence rates of animals can vary from low to greater than 30%. Salmonella prevalence in fed cattle is typically less than 10% but about 38% of feedlots contain at least one positive animal; prevalence in cull dairy cows approached 20%. Within the farm environment, manure, feed, drinking water, house flies, and animal-to-animal contact are considered to play a role in the dissemination of these organisms. Results from experimental studies have shown that feed additives containing chlorate or short chain nitrocompounds may have application in the pre-harvest control of these enteric pathogens. Because neither of these technologies have yet been approved by the U.S. Food and Drug Administration, they are not at present commercially available for use by beef producers. Probiotic preparations of lactic acid bacteria have been shown to reduce E. coli O157 in cattle and their use is presently employed by some feedlots. Vaccines likewise have been reported to reduce E. coli O157:H7.