Abstract: Ochratoxin A (OTA) is an important mycotoxin that contaminates a variety of agricultural products, thus posing a serious threat on the health of humans and animals. To find a new method for the biological detoxification of OTA in vitro, in this study, we attempted to isolate and screen intestinal bacteria from mice for OTA detoxification. Firstly, BALB/c mice were fed on a diet containing 210 μg of OTA per kg of body mass, and their faeces were collected for successive isolation of 12 strains capable of growing well at high OTA concentration using solid Luria-Bertani (LB) medium with a certain concentration of OTA. All these strains were cultivated in liquid LB broth for 20 h and their OTA-detoxifying abilities were then tested by high performance liquid chromatography (HPLC). The results showed that one strain, named YH7, exhibited strong ability to remove OTA with a maximum efficiency of 84.6%. Then YH7 was identified as Escherichia coli by its morphological features and 16s rDNA sequencing. This strain grew best at pH 7.5 and 37 ℃ with shaking at 200 r/min.

Key words: ochratoxin A, intestinal microflora, biological detoxification, screening, identification