Microbiological profiles of fresh water catfish

Abstract

The bacterial flora of live catfish was influenced by the flora of the pond water. The interaction of water volume and temperature, and the number and size of fish in the pond determined the flora of the water. These interactions influenced the presence of salmonellae as a member of the bacterial flora of the water and the fish. The correlation of aerobic plate count to coliform count (r=0.86) on freshly dressed catfish, and the correlation of the skin flora to the dressed fish flora (r=0.73) indicated that the presence of salmonellae on the skin could result in salmonellae contamination of the dressed carcass. Salmonellae contamination on dressed catfish was more prevalent on the visceral cavity than on the tail area of the carcass. Recovery of salmonellae was enhanced by using 43 C as the preenrichment incubation temperature, while contact sampling (rinse and swab) were inferior to blending and immersion of the whole fish. Salmonellae was not found on imported, frozen catfish at the retail market, but nine percent of the domestic, fresh, dressed catfish samples were positive for salmonellae. An enrichment medium specifically for Edwardsiella detection was developed, and the recovery of Edwardsiella with this medium indicated that Edwardsiella may be more prevalent in the aquatic environment than has been reported.