"A quantitative microbiological exposure assessment model for bacillus cereus in packaged rice cakes with thermal processing"

Abstract

"The objective of this study was to develop quantitative microbial exposure assessment models for Bacillus cereus in packaged rice cakes (PRC). Probability distribution for growth of B. cereus in PRC was estimated and effects of thermal processing and acidification on extending the shelf-life of PRC were quantitatively assessed. Heat penetration curves at cold point for retort process and pasteurization were successfully predicted using heat transfer simulation model (RMSE < 0.77 ºC). The retort process showed a better sterilization effect than the pasteurization process, but degraded the quality of rice cakes such as color, shape, and texture. The final contamination level in PRC of slab shape package (> 6.63 log CFU/g at 95% level) was lower than that in randomly packed sample (> 7.77 log CFU/g at 95% level) because the cold point in the slab shape package was closer to the surface. Acidification significantly inhibited the growth of B. cereus and also affected the inactivation of B. cereus. A combination of acidification and low temperature pasteurization extended the shelf-life of PRC, while minimizing quality degradation of products (< 0.43 log CFU/g at 95% level)."