Thermal inactivation of Aspergillus flavus in peanut kernels as influenced by temperature, water activity and heating rate

Food Microbiology
Shuang ZhangShaojin Wang

Abstract

Infection of Aspergillus flavus, which can produce aflatoxin, is a major problem for peanut safe storage. Thermal inactivation kinetics of Aspergillus flavus is essential to design an effective heat treatment process. In this study, thermal inactivation kinetics of Aspergillus flavus in peanut kernel flour at four water activity (aw) levels (0.720, 0.783, 0.846, and 0.921) with three temperatures for each aw was studied using a thermal-death-time heating block system and fitted with first-order kinetic and Weibull models. The influence of heating rates on thermotolerance of Aspergillus flavus was also investigated. The results showed that the Weibull distribution model had better coefficient of determination from 0.954 to 0.996, as compared to that (from 0.866 to 0.980) of the first-order kinetic model. An upward concavity was found with the inactivation curve, indicating a tailing effect. Model parameters (D, δ, and p) were estimated with the modified Bigelow equations to predict survival curves of Aspergillus flavus at any temperature and aw. The reduced heat resistance of Aspergillus flavus at high heating rates above 1 °C/min suggests that developing fast thermal processes is preferred for pasteurizing peanuts in food indus...Continue Reading

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Aspergillosis is the name given to a wide variety of diseases caused by infection by fungi of the genus Aspergillus. Aspergillosis occurs in chronic or acute forms which are clinically very distinct. Most cases of acute aspergillosis occur in patients with severely compromised immune systems. Chronic colonization or infection can cause complications in people with underlying respiratory illnesses. Discover the latest research on aspergillosis here.

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