Purpose: Evaluate the preservation and palatability effects of buffered vinegar combined with citric acid and/or succinic acid in semi-moist pet treats.
Methods: Agar dilution assays were used to determine Minimum Inhibitory Concentrations (MIC) of buffered vinegar-acid combinations against Penicillium chrysogenum and Eurotium rubrum. Additionally, semi-moist treats were manufactured with 0.6% of buffered vinegar with citric acid in Trial A and 1.0 % of both buffered vinegar acid combinations in Trial B. Cultured whey and potassium sorbate were also evaluated. Efficacy was determined by triplicate inoculation with E. rubrum spores at 105, 104 and 103 CFU/ml. Un-inoculated treats were retained for shelf-life analysis. The number of days until visible mycelial growth occurred was recorded. The impact of treatments on palatability was assessed in two pal tests with 20 dogs over two days. Significant differences in intake ratio were determined.
Results: In agar tests, the MIC of all combinations was found to be 0.6% for Penicillium and 1.0% for Eurotium. Eurotium-inoculated treats were preserved for at up to 30 days in trial A and 90 days in trial B. Untreated and cultured whey treats spoiled in an average of 5 days. Buffered vinegar-acid combinations continue to suppress spoilage in real-time shelf-life treat studies (5 to 7 months), comparable to potassium sorbate. Dog palatability results indicated a significant preference for buffered vinegar treats (P<0.05).
Significance: This work demonstrates the potential for buffered vinegar-acid blends to prevent mold spoilage in natural semi-moist pet treats without negative impact on palatability.