[Significance of the detection of staphylococcal enterotoxin A gene in low fat milk which caused a serious outbreak of food XXXX ].

@entity1 @entity794 @entity7885 @entity4968
In June 2000, there was a large-scale outbreak of food @entity4968 after consumption of Snow Brand low fat milk. In the evening of a day the incident made public, some cartons of low fat milk were brought to our laboratory for examination. Next day, we detected only @entity7885 gene among SE (A-E) genes by PCR in left-over milk samples or samples from the same lots that @entity1 had consumed. We presumed that the outbreak was caused by the intake of SEA. We subsequently confirmed the presence of SEA in these samples. To investigate the existence of SE (A-E) genes in milk, we examined 100 samples of commercial low fat milk and milk by PCR, but none of the genes was detected. We estimated the detection limit of SEA gene in low fat milk by PCR. Four strains of SEA-producing @entity794 cultures were serially diluted in low fat milk. The SEA gene was detected at levels of 5.5 x 10(2) to 1.6 x 10(4) cfu/mL of @entity794 . These amounts of @entity794 are higher than the values in raw milk reported previously. Therefore we consider that SE genes in low fat milk should usually be undetectable by our PCR. This study shows that quick detection of SE genes by PCR is very helpful to analyze outbreaks, especially if no significant bacterium can be cultured.
