|CHEN, DONGJIE - University Of Minnesota|
|MOSHER, WES - University Of Minnesota|
|WIERTZEMA, JUSTIN - University Of Minnesota|
|PENG, PENG - University Of Minnesota|
|MIN, MIN - University Of Minnesota|
|CHENG, YANLING - University Of Minnesota|
|AN, JUN - University Of Minnesota|
|MA, YIWEI - University Of Minnesota|
|BAUMLER, DAVID - University Of Minnesota|
|CHEN, CHI - University Of Minnesota|
|CHEN, PAUL - University Of Minnesota|
|RUAN, ROGER - University Of Minnesota|
Submitted to: Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/13/2020
Publication Date: 11/15/2020
Citation: Chen, D., Mosher, W., Wiertzema, J., Peng, P., Min, M., Cheng, Y., An, J., Ma, Y., Fan, X., Niemira, B.A., Baumler, D.J., Chen, C., Chen, P., Ruan, R. 2020. Effects of the intense pulsed light and gamma radiation on Bacillus cereus spores in mesquite pod flour. Food Chemistry. 344, p.128675.
Interpretive Summary: Mesquite pod flour, characterized by a unique chocolate-coconut flavor and aroma, is preferred by many consumers. However, the flour is often contaminated with Bacillus cereus, a pathogenic bacterium causing diarrhea and vomiting. Non-thermal techniques are needed to decontaminate the food because heating causes a decline in its characteristic flavor and aroma. In the present study, two non-thermal processes: intense pulsed light and gamma radiation were evaluated for their abilities to inactivate the spore forming bacteria Bacillus cereus in mesquite flour. Results showed that both gamma radiation and intense pulsed light technologies can effectively and rapidly reduce the populations of the bacterial spore by 97%, and none of the processing technologies causes any significant change in typical odor compounds or has obvious cytotoxic impact on human cells. The information is of value to food processor in decontaminating mesquite flour and other low moisture foods.
Technical Abstract: Mesquite pod flour is characterized by a unique chocolate-coconut flavor and aroma, popular among consumers. However, mesquite pods are naturally contaminated with Bacillus cereus spores due to the presence of wildlife and grazing domestic animals. Heating to a temperature beyond 60 ºC causes a decline in flavor. Therefore, non-thermal processes such as intense pulsed light (IPL) and gamma radiation were evaluated for their abilities to inactivate the spore forming bacteria B. cereus in mesquite flour. The results showed that 3.51 log CFU per gram reduction of B. cereus spore was achieved with 8 kGy of gamma radiation, and up to 1.69 log CFU per gram reduction could be achieved after 28 second IPL combined with titanium dioxide. Furthermore, the sensitive physiochemical properties including color, fatty acid metabolism, and volatile fatty acids of mesquite flour were evaluated. At the same disinfection levels, 28 second IPL induced significantly less color change but more fatty acid metabolism derived products than 2 kGy-gamma radiation. Neither treatment caused significant changes in typical odor compounds in mesquite flour. The Caco-2 cell viability analysis indicated that neither technologies induced significant cytotoxicity in the treated samples. Overall, our results suggested that both technologies are effective and could be used for decontaminating mesquite flour.