Estimating Escherichia coli Contamination Spread in Ground Beef Production Using a Discrete Probability Model

Human illness due to contamination of food by pathogenic strains of Escherichia coli is a serious public health concern and can cause significant economic losses in the food industry. Undercooked ground beef is the primary means of transmission of pathogenic E. coli to humans. In the Western world, most ground beef is produced in large facilities where many carcasses are butchered and various pieces of them are ground together in large batches. Assuming that the source of contamination is a single carcass, the primary determinant of how many batches of ground beef from a particular production cycle are affected is the manner in which pieces of that carcass are spread about in the raw sources that contribute to the ground beef batches. Assuming that ground beef from a particular batch has been identified at the consumer end as contaminated by E. coli, we model the probability that previous and subsequent batches generated in the same production cycle are also contaminated. This model may help the beef industry to identify the likelihood of contamination in other batches and potentially save money by not needing to cook or recall unaffected batches of ground beef.