Rapid detection of Escherichia coli O157:H7 in food using enrichment and real-time polymerase chain reaction

Escherichia coli O157:H7 may contaminate various types of meat products and cause diarrhea and vomiting, and also more serious complications such as haemorrhagic colitis and haemolytic-uremic syndrome (HUS) in humans. Traditional microbiological analyses to detect this pathogen are labour-intensive and time-consuming. The objective of this study was to evaluate a real-time polymerase chain reaction (PCR) for detection of E. coli O157:H7 in raw and ready-to-eat meat products. The detection limit of real-time PCR determined on pure culture was 1.1 x 10(2) CFU.ml(-1) when DNA was obtained by lysing cells and 30.6 pg.mu l(-1) when DNA was isolated and purified. Following a 20 h enrichment of a food sample in universal enrichment broth (UPB), the real-time PCR assay could detect 1.6 CFU.per 10 g of E. coli O157:H7 in chicken juice, raw beef, minced beef, beefsteak tartare, brunch beef and beefburger with background flora in the range of <10(2) CFU.g(-1) to 2.1 x 10(6) CF.mu g(-1). The applied method could be a useful tool for rapid detection of E. coli O157:H7 in raw meat and ready-to-eat meat products.