Non-thermal plasma inhibited the growth and aflatoxins production of Aspergillus flavus, degraded aflatoxin B1 and its potential mechanisms

Abstract

Aspergillus flavus (A. flavus) and its toxic metabolites, aflatoxins, are widely distributed in agricultural products and foods, posing a grave threat to food safety and public health. This study investigated the decontamination effects and mechanism of non-thermal plasma (NTP) on A. flavus and aflatoxins. NTP primarily generated reactive oxygen and nitrogen species (RONS), effectively inactivating A. flavus spores via the Weibull + Tail model. The results of ultrastructural observation and membrane integrity revealed that fungal inactivation by NTP was mainly attributed to intracellular destruction rather than the direct damage of cell membranes. Furthermore, NTP induced the accumulation of intracellular ROS and NO, disrupting anti-oxidative and energy metabolic systems, thereby inducing fungal apoptosis via a caspase-dependent mitochondrial pathway, which is responsible for A. flavus spore inactivation. In addition, the results showed that NTP reduced aflatoxin B1 (AFB1) production by regulating the expression of key genes in the aflatoxin biosynthetic pathway. Moreover, NTP effectively degraded AFB1 by disintegrating the furan ring, modifying the methoxy group, and forming the double bond in cyclopentanone, thereby decreasing the toxicity of AFB1. Hence, NTP exhibits exceptional decontamination effects against A. flavus and AFB1 via fungal inactivation, aflatoxin biosynthesis suppression, and AFB1 degradation, making it a viable alternative strategy for agricultural disinfection.