|Hwang, Cheng An|
Submitted to: Food Control
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/28/2018
Publication Date: 9/28/2018
Citation: Hwang, C., Huang, L. 2018. Growth and survival of bacillus cereus from spores in cooked rice-one-step dynamic analysis and predictive modeling. Food Control. 96:403-409. https://doi.org/10.1016/j.foodcont.2018.09.036.
Interpretive Summary: Bacillus cereus food poisoning occurs worldwide and the majority is caused by cooked starchy foods. This study modeled the growth and survival of B. cereus in cooked rice under changing temperature conditions. A dynamic model was developed and can be used to predict the growth and survival of B. cereus. The model can be used to conduct risk assessment of B. cereus cooked rice and other starch-based products during manufacturing, storage, and serving.
Technical Abstract: Bacillus cereus is a spore-forming foodborne pathogen that can produce toxins causing emetic or diarrheal intoxication. Food poisoning caused by B. cereus is a significant public health concern as it is frequently associated with the consumption of starch-based food products, which are a staple food worldwide. The objective of this study was to investigate the growth and survival of B. cereus in cooked rice using a cocktail of 7 strains of the bacterial spores dynamically between 1 and 48°C. A one-step dynamic analysis was used to directly construct a tertiary model to describe the growth and survival of B. cereus and estimate the kinetic parameters. The results of one-step dynamic analysis showed that the minimum, optimum, and maximum growth temperatures were 8.2, 37.6, and 46.8°C, respectively, with an optimum specific growth rate of 2.21 ln CFU/g/h. These parameters were in agreement with the reported growth kinetics of this microorganism. In addition, this study found that B. cereus would die off gradually at the rate of 1.21 × 10-3 log CFU/g/h per °C below its minimum growth temperature. The tertiary model was validated using three dynamic growth and survival curves. The results showed that the root-mean-square-error of prediction was 0.5 log CFU/g, suggesting that the model is reasonably accurate in predicting the growth of B. cereus in cooked rice. The results of this study can be used to predict the growth and survival of B. cereus and assess its risk in cooked rice or other starch-based products exposed to a relatively wide range of temperatures during manufacturing and distribution.