|
KMID : 0380620100420030361
|
|
Korean Journal of Food Science and Technology
2010 Volume.42 No. 3 p.361 ~ p.367
|
|
|
Toxin Gene Analysis of Bacillus cereus and Bacillus thuringiensis Isolated from Cooked Rice
|
|
Jeon Jong-Hyuk
Park Jong-Hyun
|
|
|
Abstract
|
|
|
|
Bacterial contamination of cooked rice was analyzed to evaluate the microbial safety. Thirty raw rice samples were collected in Korea and cooked in an electric rice cooker. Mesophilic aerobe, food-poisoning Bacillus cereus group, and their toxin genes were determined on cooked rice. The percentage of total mesophilic aerobe based on 1-3 log CFU/g was 27% among the samples. Bacillus spp. in MYP selective medium was similar to the number of mesophilic aerobe, whileas Bacillus spp. was detected in most samples after enrichment. Thirty-seven isolates from 30 cooked rices were identified as B. thuringiensis, B. cereus, B. valismortis, B. pumilus, B. coagulans, B. licheniformis, Geobacillus stearothermophilus, and Brevibacillus laterosporus. Twenty isolates (54%), more than half of the isolates, were B. thuringiensis while nine (27%) were identified as B. cereus. All B. thuringiensis isolates possessed non-hemolytic toxin genes and interestingly, seven B. cereus among nine isolates possessed emetic toxin genes. More B. thuringiensis was present on the cooked rice than B. cereus and most B. cereus possessed emetic toxin genes rather than diarrheal toxin genes. Therefore, food-borne outbreak due to B.cereus on the cooked rice kept at room temperature might be examples of emetic food-poisoning.
|
|
|
KEYWORD
|
|
|
cooked rice, mesophilic aerobe, B. thuringiensis, B. cereus, emetic toxin gene
|
|
|
FullTexts / Linksout information
|
|
|
|
|
|
Listed journal information
|
|
|
|