Perspective of biological fight against fungal germs contaminant corn (Zea mays): Case of the use of lactic bacteria

Abstract

Moulds are contaminants of foodstuffs, particularly cereals. They produce toxins with harmful effects on consumer health. The objective of this work was to select isolates of lactic acid bacteria (LAB) from maize ( Zea mays ), with antifungal activity, for a probable biological control of fungal germs contaminating maize. Thus, the microbiological analysis of the fermented maize paste allowed the isolation of forty (40) isolates of lactic bacteria, including 3 bacilli (7.5%) heterofermentative, 10 bacilli (25%) homofermentative and 27 cocci (67.5%) homofermentative. The comparison test between mycotoxin-producing moulds of the genus Aspergillus (flavus and niger), Fusarium sp and Penicilium sp and each isolate of lactic acid bacteria, carried out on MRS agar (CondiLab, Spain), revealed their inhibitory effect on the growth of these moulds from maize. Of the 40 LAB isolates obtained during the 3 days of fermentation, 34 (85%) isolates showed antagonistic activity on the 4 fungal germs tested. The isolates LABT0.2, LABT0.7, LABT1.6, LABT1.7, LABT2.10, LABT3.2, LABT3.4, LABT3.6, LABT3.9 and LABT3.10 were the ones with very good antifungal activity, with inhibition diameters ranging from 5.0 ± 0.0 to 7.1 ±0.14 cm. In sum, this study revealed the existence of lactic acid bacteria with antifungal activity, which can be exploited for biological control of cereal contaminants in general, and those of maize in particular, with a view to guaranteeing the safety of food for human consumption.