UPTAKE AND RETENTION OF SALMONELLA BY BIVALVE SHELLFISH

The sensitivity of detecting Salmonella in seawater by the means of bi valve molluscs has been tested. Mussels were artificially contaminated by seawater inoculated by a Salmonella suspension at five different c oncentrations. Mussel contamination by Salmonella was effective and ra pid. The presence of Salmonella was detected in mussel tissue (25 g) f rom Salmonella concentrations in seawater as low as 3.5 CFU per litre by both a conventional method and the ORGANON ELISA technique. The ELI SA rapid method was in agreement with the conventional technique and i ts sensibility and selectivity were respectively 94.3% and 88.8%. A st udy of Salmonella retention in oysters, artificially contaminated at a low level and stored in air at 12-15-degrees-C has shown that these b acteria were still detectable after a five day-period. The survival of Salmonella in mussels and oysters, air-stored at 10-degrees-C, was fo llowed by a direct Salmonella enumeration from individual bivalves. A storage period as long as twenty days did not produce appreciable chan ges in Salmonella counts in these shellfish.