Antifungal activity of lactic acid bacteria isolated from milk against Penicillium commune, P. nordicum, and P. verrucosum

Abstract

Penicillium spp. is considered a major spoilage fungus of cheeses. The use of lactic acid bacteria (LAB) with antifungal activity is an interesting possibility of biopreservation. In this study, the isolation and characterization of anti-Penicillium LAB from milk was carried out. Ninety-three milk samples were analysed and a total of 57 strains of LAB active against P. nordicum were isolated, mainly from goat and cow milk. Thirty-four isolates with strong activity were selected and identified, Lacticaseibacillus casei (11), L. paracasei (9) and L. rhamnosus (5) being the dominant species. The antifungal spectrum of these 34 LAB against strains of P. commune and P. verrucosum was investigated. L. casei, L. paracasei and L. rhamnosus were the most active and P. nordicum was the most susceptible fungus. Two isolates (L. casei Lc-51/3 and L. paracasei Lp-25/1) with high antifungal activity showed a moderate to high reduction on the growth of Penicillium nordicum and, in a lesser extent, of P. commune, and also a reducing effect on the ochratoxin A and cyclopiazonic acid production. In addition, these isolates demonstrated activity against several food pahogens. These findings indicate their suitability for the development of protective adjunct starters against spoilage and toxigenic microorganisms in cheese processing.

Keywords: Antifungal activity; Cheese; Cyclopiazonic acid; Lacticaseibacillus; Ochratoxin A; Penicillium.