Qualitative vs quantitative microbiology

Abstract

Escherichia coli O157 and Salmonella are food-borne pathogens of importance to the Australian beef and dairy industries. Cattle are a significant reservoir for both of these pathogens and beef has been the source of food-borne outbreaks of both E. coli O157 and Salmonella. The presence of pathogens in cattle can lead to contamination of carcasses during slaughter and products produced from these contaminated carcasses pose a risk to consumers. However, the magnitude of the risk is not clear. Until recently, almost all of the information published on E. coli O157 and Salmonella in cattle has consisted of only qualitative information i.e. the prevalence of these organisms in cattle. In order to estimate risk, it is important to understand not only how many cattle shed E. coli O157 and Salmonella but also the number of pathogens shed.