Evaluation of Direct Enrichment at Elevated Temperature for Recovery of Salmonellae from Oysters1

Abstract

A comparison of the recovery of salmonellae from naturally contaminated oysters was made by using either Lactose broth preenrichment at 35°C followed by selective enrichment in Tetrathionate and Selenite Cystine broths at 35, 41 and 43°C, or direct enrichment in Tetrathionate and Selenite Cystine broths with incubation at 35, 41 and 43°C. Direct enrichment in Selenite Cystine broth at both elevated temperatures produced the greatest number of positive samples. Similar results were obtained with artificially contaminated oyster samples (1 Salmonella/5 g of meat). Statistical analysis of the data showed that significantly higher recovery of salmonellae was obtained by using direct enrichment of samples in Selenite Cystine broth at the elevated temperature.