ANTIFUNGAL EFFECTIVENESS OF METABOLITES PRODUCED BY LACTIC ACID BACTERIA

TORRES M.J.; GEREZ C.L.; TORRES LEAL G.; FONT DE VALDEZ G ; ROLLÁN G.

Tafí del Valle, Tucumán, Argentina.

Jornada; XXIV Jornadas Científicas Asociación de Biología de Tucumán.; 2007

Asociación de Biología de Tucumán.

The antifungal activity of lactic acid bacteria (LAB) was demonstrated in previous studies. The aim of this work was to identify the biofungicide compounds (BF) and to evaluate their effectiveness with respect to the chemical additives (CA) used in industry for conservation purposes. The BF were identified in the LAB cultures by the HPLC method. The ability of the BF to inhibit conidia germination was evaluated. BF are acidic in nature and related to lactic, acetic, and phenyl lactic acid (PLA). The antifungal activity was directly proportional to the acid concentration and depended on the fungus species. Lactic acid was the least and PLA the most effective BF identified. The effectiveness of the BF was determined by comparing its lethal dose 80 (LD) to that of different CAs. Sorbate, a CA frequently used in the food industry, showed lower effectiveness (LD: 35mM) than PLA (LD: 21mM). The inhibitory effect of CA was directly correlated to its concentration, with the exception of imazalyl activity, which decreased at greater concentrations. The use of BAL and/or the BF as a Bio-conservative is an alternative to reduce the use of CA in the agro industry