Phytosterol effects on yogurt microflora

Phytosterols play a major role in functional foods. These sterols are now being added to various dairy based products. The researchers in this study investigated the potential antimicrobial activity of phytosterols in milk and their effect on yogurt starter cultures. They found that a commercial phytosterol preparation had no effect on the standard plate count and psychrotroph population in pasteurized milk stored at 4 °C. In addition, a challenge study employing Pseudomonas spp. in milk at 4 to 7 °C confirmed that the CPP was not antimicrobial.

The phytosterol preparation had no effect on the development by Lactobacillus bulgaricus and Streptococcus thermophilus during yogurt production at 33 °C and storage at 4 °C for 30 d. The researchers see this as beneficial since growth and acid development by these organisms are crucial for yogurt quality. They found that while the commercial preparation was somewhat antimicrobial when formulated with dispersing agents, it otherwise had no antimicrobial activity.

For more, see Journal of Food Science