2018 Volume 69 Issue 7 Pages 496-502
We examined bacteria populations in uncooked rice samples from Korea, the Philippines, Thailand, and Japan using standard plate counts (SPCs), coliform bacteria counts, and Bacillus cereus counts. A total of 81 samples were collected. SPCs in rice sampled from homes and markets in Japan and from markets in Korea were similar (Log 3.5 – 3.9 SPCs/g). However, SPCs in rice samples from markets in the Philippines and Thailand were significantly lower (Log 2.5 – 2.8 SPCs/g). Coliform bacilli were isolated from samples from Japan and Korea. B. cereus (enterotoxin positive and cereulide biosynthesis gene negative) was isolated from one milled sample from Japan, one milled sample from the Philippines, and four milled samples from Thailand. B. cereus in positive rice samples ranged from Log 2.5 – 2.9 CFUs/g. However, no B. cereus was detected in samples subjected to heat treatment at 98℃ for 20 min. These results suggest that the risk of foodborne illness due to B. cereus in cooked rice is low, but enterotoxin-positive B. cereus was detected in milled samples. To prevent cross-contamination, food hygiene is therefore extremely important during food preparation and storage.
