Probiotic Fermented Cow’s and Goat’s Milks: Determination of Biogenic Amines and Sensory Acceptance

Introduction: Fermented milks are a traditional food created as a means of preserving fresh milk, and the addition of probiotic bacteria into fermented milks adds value with respect to their potential functional benefits. However, some genera of microorganisms with potential probiotic characteristics possess the ability to form bioactive amines.

Purpose:   The behavior of biogenic amines (tyramine, putrescine, cadaverine, spermidine and histamine) in fermented milks – usually cow’s and goat’s raw milk - added with probiotic bacteria during ten days of chilled storage was evaluated. Additionally, a quantitative consumer test was conducted with 40 consumers to assess the products’ acceptability.

Methods: For the fermentation process, using 4x10⁸ CFU/ml of lyophilized Lactobacillus acidophilus LA-5^®, Bifidobacterium lactis BB-12^®and Streptococcus thermophilus(Chr.Hansen), the samples remained in the oven at 40 ± 2°C for 8 hours, and the fermentation process was interrupted when the pH reached 4.5. Finally, the product was packaged in 200ml plastic pots and stored at 4 ± 1°C for 10 days. Biogenic amines were quantified during 10 days of chilled storage by HPLC-PDA. The sensory evaluation was assessed by a hedonic test. The results were subjected to one-way ANOVA followed by Tukey test using the software GraphPad Prisma 5.

Results:   Initial elevated tyramine levels were observed in both products and its content increased throughout the storage period. The highest yield of biogenic amines occurred between the first and fifth day of storage, and a decrease in the content of such compounds occurred thereafter. A higher overall sensory acceptance of the cow’s fermented milk was observed.

Significance:   The results suggest that, even in a preliminary assessment, the content of biogenic amines may be a criterion for selecting (probiotic) lactic acid bacteria to develop fermented milks.