Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: 12/23/2004
Publication Date: 8/1/2005
Citation: Fratamico, P.M., Gehring, A.G., Karns, J.S., Van Kessel, J.S. 2005. Detecting pathogens in cattle and meat. Book Chapter. Improving the Safety of Fresh Meat, Woodhead Publishing Ltd., Cambridge, UK pg:25-55 Interpretive Summary:
Technical Abstract: Detection, isolation, and identification of microorganisms in food, animals, and environmental samples have historically relied on traditional culture techniques that utilize specialized microbiological media. Although culture techniques have long been regarded as the 'gold standard', they are labor intensive and yield results after several days of repeated culture and confirmation steps. Over recent years, advances in biotechnology have led to the development of 'rapid methods', including immunologic- and genetic-based assays that expedite the detection process. Traditional culture techniques, as well as rapid assays, including the polymerase chain reaction (PCR) and enzyme immunoassays, have been used to detect pathogens such as Salmonella spp., Escherichia coli O157:H7, Campylobacter spp., Listeria monocytogenes, and Yersinia enterocolitica in cattle, other food animals, and foods of animal origin. Currently, there is a zero tolerance policy for E. coli O157:H7 in non-intact fresh beef products such as ground beef; therefore, methods should have the ability to detect one colony forming unit (CFU) in samples under analysis. Food analysis, however, is not free of limitations. Problems that complicate pathogen detection include (1) non-homogenous distribution of pathogens; (2) pathogens present at levels much lower than that of the indigenous microflora; (3) interference of sample matrix components with growth or detection of the target organism; and (4) failure of recovery of injured pathogens using selective enrichment media. Testing for zoonotic bacterial pathogens in animal production farms requires the analysis of a variety of sample types, including feces, manure, feed, water, insects, and wildlife, such as rodents, raccoons, deer, and birds, and no 'standard' methods for detection of particular pathogens currently exist. Before the use of novel technologies, such as DNA or antibody microarrays, for routine screening of meat and carcasses for the presence of pathogenic organisms becomes a reality, additional research in the development of rapid, sensitive, and inexpensive assay systems for high-throughput automated sample processing and detection is critical. Ideally, detection systems should have the capability to screen for pathogens in real-time on the production line, and if progress in methods development continues at the current pace, this may soon become a reality.