Abstract
Between 1986 and 1996, bacterial contamination of 1, 445 commercial raw fish and shellfish in Tama, Tokyo was investigated. Each year, the median of standard plate counts decreased, whereas that of the coliform group was nearly constant. Vibrio parahaemolyticus was detected in 71 (4.9%) samples, and high contamination was observed in shellfish such as ark shell (25 samples). Staphylococcus aureus was also detected in 77 (5.3%) samples, especially tuna (24 samples). In addition, Bacillus cereus was found in 25 (1.7%) samples, but no Salmonella was detected.
By introducing enriched cultures for S. aureus, the detection ratio markedly increased, and marked contamination in tuna was observed. In the testing of coagulase and enterotoxin on the 105 strains of S. aureus, all isolates were typable to 8 different kinds of coagulase type, but enterotoxigenicity was confirmed in only 29 strains.
