Protection capacity of Lactiplantibacillus plantarum 83114 against contamination of dry pet food with Aspergillus flavus

A wide range of pet food types are available on the market and one of the most common ingredients of dry food are cereals, vectors of harmful mycotoxins. Mycotoxins are toxic secondary fungal metabolites that contaminate dry pet food and their levels remain stable during food processing. This has a direct effect on the quality of the product and on animal health. Lactiplantibacillus plantarum 83114 is a probiotic strain isolated from traditional fermented milk with proven antifungal activity in different matrix. This study investigated the antifungal activities of this strain against contamination of dry pet food with a mycotoxigenic Aspergillus flavus strain. The antifungal activity was assessed using a complete culture of viable L. plantarum 83114, cell free supernatants (CFS), and non-viable cells (postbiotics). The CFS of L. plantarum CIDCA 83114 (pH 4.04) exhibited a high germination reduction rate (GR 94.7 %). However, the neutralized CFS (pH 7.0) lost approximately 60 % of its inhibitory capacity. L. plantarum CIDCA 83114 CFS and postbiotic treatments at 50 % exerted a total fungal growth inhibition, observed in a growth rate (KD) of zero. The viability of L. plantarum 83114 inoculated in dry pet food decreased by one logarithmic order after the first week of storage and, by the second week, no viable cells were detected. The DNA concentration of A. flavus in dry pet food supplemented with the probiotic strain remained consistently low and stable throughout the storage period. Lactiplantibacillus plantarum 83114 played a crucial role in inhibiting fungal growth and could act as a biopreservative agent in pet food.