A total of 1, 019 samples of milk, meat and fish and their products were examined for the incidence of Staphylococcus aureus and the production of staphylococcal enterotoxin from strains isolated between 1995 and 1998 in China. Overall, 381 samples (37.4%) were contaminated with S. aureus. The rate of isolation was 46.7% for raw milk, 6.3% for dairy products, 73.6% for chicken meat, 29.5% for pork, 25.0% for beef, 19.5% for meat products and 30.9% for fish and shellfish. None of S. aureus was found in yoghurt and dry milk. Fortyeight (33.1%) of the 145 isolates from milk and dairy products, 61 (29.5%) of 207 isolates from meat and meat products, and 6 (20.7%) of 29 isolates from fish and shellfish produced staphylococcal enterotoxin, types A to E, respectively. The most predominant type was C, followed by A and B.
Lactic acid bacteria belonging to the human normal flora of the mouth and intestine were used for fermented food as starter cultures. In salted vegetables fermented by lactic acid bacteria, the fermentation of lactic acid bacteria was markedly affected by salt concentration. A sample of 23 salted vegetables were purchased from a retail shop in Tokyo, and 2 homemade samples were also used. A total of 164 strains of lactic acid bacteria were isolated from 19 samples. For the fermentation test, API 50 CH galley and CHL medium were used according to the manufacture's instructions, and identification of species of lactic acid bacteria was performed using API 50 kit and Bergey's manual. Lactic acid bacteria levels ranged between 104 cfu/g and 108 cfu/g widely. The isolated lactic acid bacteria were Lactobacillus, Lactococcus, Leuconostoc and Pediococcus. The predominant species were Leuconostoc mesenteroides and Lactococcus lactis.