Maize-Derived Lactic Acid Bacteria with Probiotic Traits and Antifungal Activity: Candidate Functional Starter Cultures and Bio-Preservatives

Contamination of agricultural products such as maize by fungi is a significant concern worldwide, as it can compromise food safety and quality. In recent years, the use of microorganisms as natural food preservatives has gained interest. Probiotic lactic acid bacteria (LAB) and their metabolites are considered a promising strategy to reduce fungal growth and limit other food contaminants. This study aimed to characterize, screen and compare the probiotic properties and antifungal activity of LAB of maize origin. A total of 23 LAB isolates obtained from untreated maize grains were identified through 16S rRNA gene sequencing as Weissella viridenscens (34.7%), Pediococcus pentosaceus (34.7%), Enterococcus durans (17.4%), Leuconostoc citreum (9%), and Enterococcus faecium (4.3%). All isolates demonstrated acid, phenol, and bile salt tolerance; surface hydrophobicity; and antagonistic activity against selected bacterial foodborne pathogens. Notably, Enterococcus sp. showed the strongest inhibitory activity against Escherichia coli ATCC 5211 (21 mm inhibition zone) and Staphylococcus aureus (17 mm inhibition zone), whereas Pediococcus sp. exhibited the highest antagonistic effect against Listeria monocytogenes (18.7 mm inhibition zone). Furthermore, E. durans and P. pentosaceus demonstrated the strongest antifungal activity, effectively inhibiting the growth of Alternaria tenuissima (F22FR) and Fusarium oxysporum (F44FR), respectively. Overall, all the LAB strains isolated from this study showed considerable potential for use in the food industry as probiotics, starter cultures for functional food fermentations, bio-preservatives and biocontrol agents against toxigenic fungi and pathogenic bacteria, with E. durans standing out for its exceptional performance. Future research will explore the ability of these isolates and/or their enzymes to degrade mycotoxins commonly found in maize, a staple food in many African countries.