Enterotoxigenic Escherichia coli and Staphylococcus aureus in fish and seafood from the southern region of Brazil.

An investigation to evaluate the microbiological condition and safety of fish and seafood commonly harvested at the coast of Santa Catarina State and sold in Florianópolis was undertaken. One hundred and seventy-five samples of fish and fish fillets (Cynoscion leiarchus), shrimp tails (Peneaus paulensis), shellfish-meat (Anomalocardia brasiliensis and Metilus edulis), and crab-meat (Callinectes sapidus) were collected from markets and examined within 4 h of purchase. For isolation and enumeration of Escherichia coli the methods used were those of Speck et al. (1975) (Method 1) and Fishbein et al. (1976) (Method 2); for S. aureus, methods recommended by the U.S. Food and Drug Administration were used including biochemical identification of the strains. E. coli was more frequently detected with Method 1 than Method 2. Of 317 E. coli strains tested for STG and LT II toxins, only one (isolated from shellfish-meat) produced ST and none produced LT II toxin. S. aureus was isolated from 20% of 175 samples examined, including 60% of samples of shellfish-meat. Only nine of 109 S. aureus strains produced enterotoxins, including enterotoxin A (4), D (1) and AB (4). It is concluded that greater care must be taken to reduce contamination of fish and seafood during harvesting and post-harvest handling.