In cooked-chilled and pasteurized vegetable products, initial numbers of Bacillus cereus were below 10 cfu g(-1). Before the appearance of spoilage, numbers reached 6-8 log cfu g(-1) at 20 degrees C and 4-6 log cfu g(...
详细信息
In cooked-chilled and pasteurized vegetable products, initial numbers of Bacillus cereus were below 10 cfu g(-1). Before the appearance of spoilage, numbers reached 6-8 log cfu g(-1) at 20 degrees C and 4-6 log cfu g(-1) at 10 degrees C. Bacillus cereus was not detected in samples stored at 4 degrees C. Ten percent of strains isolated from the products were able to grow at 5 degrees C and 63% at 10 degrees C. Bacillus cereus strains unable to degrade starch, a feature linked to the production of emetic toxin, did not grow at 10 degrees C and had a higher heat resistance at 90 degrees C. Using immunochemical assays, enterotoxin was detected in the culture supernatant fluid of 97.5% of the strains. All culture supernatant fluids were cytotoxic but important variations in the level of activity were found. Psychrotrophic isolates of B. cereus were unable to grow in courgette broth at 7 degrees C whereas they grew in a rich laboratory medium. At 10 degrees C, these isolates grew in both media but lag time in courgette broth was 20-fold longer than in the rich laboratory medium.
Bacillus cereus has sometimes been implicated in food poisoning and in opportunistic infections of seriously ill patients. This report describes an unusual case of persistent bacteremia and multiple organ failure asso...
详细信息
Bacillus cereus has sometimes been implicated in food poisoning and in opportunistic infections of seriously ill patients. This report describes an unusual case of persistent bacteremia and multiple organ failure associated with B. cereus in a patient admitted to our institution for lung cancer. The patient was undergoing treatment with an antimicrobial agent (imipenem) that was shown to be effective against the micro-organism in vitro. No portal of entry for the strain was detected. After treatment with vancomycin. also shown to be effective in vitro. no clinical improvement was noted and the patient died. Molecular studies showed that the same strain caused an episode of pseudobacteremia in another patient admitted to the same ICU room.
The microbiological quality of 4,162 samples of cooked rice from restaurants and take-away premises in the United Kingdom was examined, including ready-to-eat rice purchased at point-of-sale and rice that was stored p...
详细信息
The microbiological quality of 4,162 samples of cooked rice from restaurants and take-away premises in the United Kingdom was examined, including ready-to-eat rice purchased at point-of-sale and rice that was stored precooked for reheating on demand. The majority of point-of-sale cooked rice samples (1,855 of 1,972;94%) were of acceptable microbiological quality, but 15 (1%) samples were of unacceptable quality (Bacillus spp. and B. cereus, greater than or equal to 10(5) CFU/g;Escherichia coli, greater than or equal to 10(4) CFU/g), indicating a potential risk to health. The prevalence of Bacillus spp., B. cereus, and E. coli was significantly greater in precooked stored rice than in point-of-sale cooked rice (P < 0.005 to 0.0005). Bacillus spp. (greater than or equal to 10(4) CFU/g), B. cereus (greater than or equal to 10(4) CFU/g), and E. coli (greater than or equal to 10(2) CFU/g) were present in 7%, 2%, and 9% of precooked stored samples, respectively, compared to 2%, 0.5%, and 1%, respectively in point-of-sale samples. Although final heating at the point of sale reduces the levels of microorganisms present in rice it will not inactivate the B,. cereus emetic toxin if present. Rice from Indian premises was of poorer microbiological quality than that from Chinese and other premises. Although most point-of-sale cooked rice samples (94%) were of an acceptable microbiological quality, evidence from this study indicates that the microbiological quality of cooked rice sold from certain outlets in the UK is of concern.
暂无评论