The incidence, intraspecific diversity and toxigenic profile of
Bacillus cereus in the Yellow-Water were investigated. Of 50 samples tested, 17 (34%) were contaminated by
B. cereus with 3.7 × 10
3 − 4.9 × 10
3 CFU/mL. The intraspecific diversity of
B. cereus was observed by repetitive (GTG)
5 sequence polymorphism-PCR, with six subtypes, and were further discriminated into seven subtypes by 16S-23S rRNA intergenic transcribed spacer. 94% of isolates contained at least 2 toxin genes of
nheABC,
hblCDA,
cytK,
entFM and
EM1, but 6.0% carried none of them. The detection rates of
nheABC,
hblCDA,
cytK and
entFM were 94%, 88%, 46% and 70%, respectively. All isolates with
nheABC could produce NHE, but of the isolates harbored
hblCDA, 52% was positive for HBL. Only 6.0% isolates possessed
EM1 and they were positive for emetic toxin assay. The results suggested that Yellow-Water needs stricter microbial standard as a fermented food flavor enhancer.
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