Enrichment of injuredSalmonellain poultry products for detection by polymyxin–cloth enzyme immunoassay

Abstract

Because injuredSalmonellacells have the potential to cause salmonellosis, their detection in foods is important to food safety testing programs. In pure cultures, a small number of heat-injuredSalmonella enteritidiscells were detected by the polymyxin–cloth enzyme immunoassay after 2-h static pre-enrichment in brain–heart infusion (BHI) medium supplemented with 0.05% yeast extract and 0.05% cholate (BYC), followed by overnight static enrichment in the presence of 0.3% selenite. However, in chicken carcass rinse, heat-injuredS. enteritidiscells (400 cfu ml–1) could not be detected even after 6-h pre-enrichment in BYC, while uninjured cells were detectable. Prolonged (20 h) pre-enrichment in BYC, followed by 20-h incubation of a 10-fold dilution with BYC with addition of 0.03% selenite, permitted the detection of heat-injuredS. enteritidis(less than 7 cfu ml–1) in the chicken carcass rinse.