ENRICHMENT OF INJURED SALMONELLA IN POULTRY PRODUCTS FOR DETECTION BYPOLYMYXIN-CLOTH ENZYME-IMMUNOASSAY

Because injured Salmonella cells have the potential to cause salmonell osis, their detection in foods is important to food safety testing pro grams, in pure cultures, a small number of heat-injured Salmonella ent eritidis cells were detected by the polymyxin-cloth enzyme immunoassay after 2-h static pre-enrichment in brain-heart infusion (BHI) medium supplemented with 0.5% yeast extract and 0.5% cholate (BYC), followed by overnight static enrichment in the presence of 0.3% selenite. Howev er, in chicken carcass rinse, heat-injured S. enteritidis cells (400 c fu ml(-1)) could not be detected even after 6-h pre-enrichment in BYC, while uninjured cells were detectable. Prolonged (20 h) pre-enrichmen t in BYC, followed by 20-h incubation of a 10-fold dilution with BYC w ith addition of 0.3% selenite, permitted the detection of heat-injured S. enteritidis (less than 7 cfu ml(-1)) in the chicken carcass rinse. (C) 1998 Academic Press.