OCCURRENCE AND CONTROL OF Salmonella IN FRESHWATER CATFISH

Abstract

ABSTRACT The incidence of Salmonella was determined in farm‐raised catfish and in their environment. The effect of the processing procedure on Salmonella contamination also was investigated. In addition, domestic and imported retail samples were also examined for Salmonella. Salmonella was isolated from processed farm catfish and catfish pond water. Its source could not be established in that feed, cattle manure, frogs, turtles and crayfish from the ponds were Salmonella‐negative. The detection of Salmonella in catfish and catfish pond water seemed to be enhanced by high stocking densities and water temperatures approaching 26°C. Cross‐contamination may have occurred between the skin and viscera and the finished dressed fish if Salmonella‐positive fish were not processed properly. By changing the processing procedure, the incidence of Salmonella in the finished product was reduced from 48.6 to 0%. Retail samples exhibited a wide range of total plate and coliform counts with a good correlation (0.86 farm‐raised and 0.80 wild) between the two in fresh fish. This correlation was not noted in frozen imported fish (−0.10 for Mexican and −0.0047 for Brazilian). Salmonella was isolated from only 13 of 153 (8.4%) retail samples. The overall food quality and safety of dressed cattish was good.