PSX-A-4 - Late-Breaking: Assessing the antifungal efficacy of EverWildTM D01 against Aspergillus flavus in semi-moist pet treats

Semi-moist pet treats contain moisture levels ranging from 20-30% making them ideal for mold growth and mycotoxin production. To control mold, synthetic mold inhibitors such as potassium sorbate or calcium propionate are used. Synthetic additives are effective, but there is a shift in the pet owner preferences for ‘natural’ products. Fermented and (or) cultured whey has been shown to contain antifungal metabolites and has been used to control fungal growth in bread. EverWild^TM D01 is a commercially available cultured whey product. The objective of this study was to assess the efficacy of EverWild^TM D01 against Aspergillus flavus in a semi-moist pet treat. A model semi-moist pet treat fortified to be nutritionally complete was produced with three levels of powdered whey fermentate, [1.0%, 3.0% and 5% (w/w)], a negative control with no antifungal and a “positive control” which contained potassium sorbate as a standard industrial mold inhibitor. Treats were produced by baking in 3cm x 3cm squares. Individual squares were inoculated with 0.1 mL of Aspergillus flavus (ATCC 204304) to achieve a final concentration of ~ 5.0 Log CFU/square. The inoculated squares were individually incubated at 25⁰ C. Fungal analysis was performed at day 3, 6, 9, 12, 15, 18, 21, 24 and 28 by surface plating on Potato Dextrose Agar (PDA) followed by incubation at 25⁰ C for 72h. The total log reductions were calculated by subtracting the initial inoculum with the colony counts on day 28. EverWild^TM D01 at 1.0%, 3.0%, and 5% (w/w) had a 1.90, 3.89 and 4.58 Log CFU/square log reduction, respectively. The positive control had a 1.19 Log CFU/square log reduction. All treatments differed from the negative control (P < 0.05). In conclusion, EverWild^TM D01 may be effective as a natural alternative to synthetic mold inhibitors in semi-moist pet treats.