Change of thermal inactivation of Clostridium botulinum spores during rice cooking
| Autor: | Atsushi Kobayashi, Yukifumi Konagaya, Akira Yamazaki, Hiroshi Urakami, Shunji Kozaki, Nobumasa Tanaka, Jun Hoshino, Akihiko Sasagawa |
|---|---|
| Rok vydání: | 2009 |
| Předmět: |
Botulinum Toxins
Hot Temperature Food Handling Colony Count Microbial Food Contamination medicine.disease_cause Microbiology Endospore medicine Clostridium botulinum Food microbiology Humans Clostridiaceae Food science Cooking Incubation Spores Bacterial biology Inoculation fungi food and beverages Oryza biology.organism_classification Spore Consumer Product Safety Food Microbiology Bacteria Food Science |
| Zdroj: | Journal of food protection. 72(11) |
| ISSN: | 0362-028X |
| Popis: | Cooked and packed rice (CaPR), a popular rice product in Japan, is distributed with oxygen-absorbing agents and without refrigeration. When the final product was inoculated with spores of several strains of proteolytic Clostridium botulinum at a dose of 10(3) spores per g (2 x 10(5) spores per package) and incubated at 30 degrees C, the bacteria grew and produced neurotoxins in 40 days. To simulate more realistic cases of contamination, the same dose of spores was inoculated before the cooking process. When cooked at 100 degrees C for 30 min, a small number of spores survived and the toxins were detected in some of the samples after incubation for 180 days. However, when cooked at 100 degrees C for 15 min immediately followed by 105 degrees C for 15 min, neither survivors nor the toxins were detected during incubation for 270 days after cooking. Even when inoculated with 10(5) spores per g of one of the most heat-resistant strains, 213B, viable spores were not detected after cooking. The inactivation by these heating conditions in different media indicated that the spores were inactivated >1,000-fold more in rice suspension than in cooked meat medium or phosphate buffer. It was therefore suggested that rice contains component(s) that facilitates thermal inactivation of C. botulinum. |
| Databáze: | OpenAIRE |
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