美国食品药品局细菌分析手册（BAM）第14章：蜡样芽孢杆菌（2020年10月版）BAM Chapter 14 Bacillus cereus

Bacillus cereus is an aerobic spore-forming bacterium that is commonly found in soil, on vegetables, and in many raw and processed foods. B. cereus food poisoning may occur when foods are prepared and held without adequate refrigeration for several hours before serving, with B. cereus reaching >106 cells/g. Foods incriminated in past outbreaks include cooked meat and vegetables, boiled or fried rice, vanilla sauce, custards, soups, and raw vegetable sprouts. Two types of illness have been attributed to the consumption of foods contaminated with B. cereus. The first and better known is characterized by abdominal pain and non-bloody diarrhea; it has an incubation period of 4-16 h following ingestion with symptoms that last for 12-24 h. The second, which is characterized by an acute attack of nausea and vomiting, occurs within 1-5 h after consumption of contaminated food; diarrhea is not a common feature in this type of illness1. The MYP agar has been the standard media for plating B. cereus, but it has little selectivity so background flora is not inhibited and can mask the presence of B. cereus. Bacara is a chromogenic selective and differential agar that promotes the growth and identification of B. cereus, but inhibits the growth of background flora. The chromogenic agar has been suggested for the enumeration of B. cereus group as a substitute for MYP1,2. Typical colonies will grow as pink-orange uniform colonies surrounded by a zone of precipitation. The identification would include all species from the B. cereus group: B. cereus, B. thuringiensis, B. anthracis,B. mycoides, and B. weihenstephanensis. Biochemical testing will be necessary to delineate to the species level. The Bacara media can be purchased as prepared plates or media in flasks to which two supplied reagents are added. The media has a proprietary formulation and cannot be purchased in a dehydrated form.

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