Physicochemical, microbial, and sensory characteristics of yogurt with Persian shallot (Allium hirtifolium Boiss) and probiotic bacteria.

ABSTRACT

The aim of this study was to investigate the characteristics of yogurt prepared with the addition of Persian shallot and probiotic bacteria. The effect of Persian shallot on the viability of probiotic bacteria (Lactobacillus acidophilus and Bifidobacterium bifidum) was evaluated. Furthermore, the antimicrobial effects of shallot and probiotic bacteria on Listeria monocytogenes and Escherichia coli species were investigated. The experiments were performed on days 0, 1, 7, 14, and 21. The results showed that the survival of lactic acid bacteria increased significantly in the presence of shallots (p < .05). The addition of two different probiotic bacteria to the yogurt samples inhibited the pathogenic bacteria. While E. coli bacteria had a 3-log reduction, L. monocytogenes did not grow at all in the presence of probiotic bacteria and shallots. Based on these experiments, it was concluded that the addition of shallots not only increased the survival of probiotic bacteria but also reduced the growth of food-borne pathogenic bacteria. In addition, the addition of probiotic bacteria increased the acceptance of sensory properties of yogurt samples.