Efficacy of organic acids in feed experimentally contaminated with Aspergillus flavus

Abstract Organic acids have been shown to be a promising alternative to chemical compounds due to their ability to inhibit microbial growth. The aim of this study was to evaluate the antifungal activity of organic acids in animal feed experimentally contaminated with Aspergillus flavus. The A. flavus strain (ACFV) was activated in the Sabouraud Dextrose Agar way and incubated at 25 °C for 7 days. After incubation, it was carried out the preparation of the spore suspensions and counted in a Neubauer chamber, standardizing the inoculum at 5.0 x 10-6 spores/mL. Spore suspensions (10 mm agar discs) were prepared in buffered peptone water (1000 mL) and the feeds were treated with commercial organic acids, including propionic acid or a blend of acids (propionic, tartaric, citric, formic, sorbic and lactic). The feed was analyzed on days 1, 3, 5 and 7 of shelf life, with microbiological analysis of mold and Aspergillus spp. count, in addition to measurements of water activity, dry matter, pH and temperature. Organic acids reduced the total count of filamentous fungi throughout the evaluation period. A significant reduction in Aspergillus spp. counts was observed in feeds treated with organic acids (p<0.05). Furthermore, there was a reduction in dry matter and pH in the feeds. It is concluded that organic acids have great potential to inhibit fungal growth in diets, ensuring their quality and safety during the storage.