Antifungal action of quaternary ammonium compounds against environmental molds isolated from food industries

Abstract

Molds are ubiquitously found microorganisms that are usually present as contaminants in food industrial environments. It has been shown that Cladosporium and Aspergillus genera are two of the most abundant and widely distributed in these locations because they are highly resistant species to sanitizing treatments. Hence, the search of antimicrobial compounds that are effective to these types of fungal contamination becomes relevant. The aim of this report was to evaluate the antifungal capacity of two commercial preparations made both with benzalkonium chloride (a first generation QAC) alone and with the addition of glutaraldehyde at different concentrations and contact times. A suspension-neutralization test was performed employing spores of five strains of both Aspergillus section Nigri and Cladosporium cladosporioides, all isolated from food industries environments. Results have shown that benzalkonium chloride preparation was successful in destroying Cladosporium spores at 5% (v/v) concentration (average 4D value of 9.1 min) but failed in neutralizing Aspergillus propagules at the same conditions. On the other hand, the commercial mixture made of benzalkonium chloride and glutaraldehyde was effective in the inactivation of all food spoilage fungi spores at 1% (v/v) concentration (average 4D value of 1.8 and 8.8 min for Cladosporium and Aspergillus strains, respectively).