Biocontrol of Aflatoxigenic Maize Molds Using Lactobacillus spp.-Based Formulations

Abstract

Food contamination by mold is a serious and difficult problem to manage, leading to enormous economic losses. Mycotoxins have been recognized as one of the most dangerous contaminants in food. They can be toxic to humans and animals when they reach a certain ingestion threshold. These mycotoxins include aflatoxins, produced mainly by Aspergillus section Flavi, the most frequently isolated from food being A. flavus and A. parasiticus. Current control methods, mainly physical and chemical, are showing their limitations due to the environmental problems caused, resistance developed by pathogens, and the food organoleptic quality deterioration. Other control alternatives based on biocontrol can be explored. This present study aimed to isolate Lactobacillus spp. from local foods that can inhibit aflatoxigenic molds' growth and reduce aflatoxins production. To this end, four (04) strains (04) collection namely GNc, GNd, F3a, and G3Lab1 from fura and gapal, selected on the basis of their high antifungal potential, were co-cultured with fungi reference strains (UBOCC-A-111042, UBOCC-A-106031, T1, and T2) and on maize aflatoxigenic molds (AF1, AF2, AF3, AP1, and AP2). Bioassays in vitro demonstrated that Lactobacillus spp. strains significantly inhibited fungal radial growth. Further tests were conducted on eleven (11) highly contaminated maize samples, showing a maximum reduction rate of 68% in the fungal flora. Analysis and quantification of residual aflatoxins B1, B2, G1, and G2 in maize grains using liquid chromatography coupled with tandem mass spectrometry (LC–MS/MS) revealed a decrease and, in some cases, complete suppression of aflatoxin B1, B2, G1, and G2 production in grains detoxified with Lactobacillus extracts.