What You Need to Know
During fermentation, Lactobacillus bulgaricus and Streptococcus thermophilus metabolise lactose to lactic acid, lowering pH and inducing casein micelle aggregation. The acidification rate is temperature‑dependent, with optimal activity at 40–45 °C, while inoculum size dictates the lag phase and final acid yield. Proper pasteurisation preserves whey proteins and prevents unwanted microflora, enabling a stable gel network.
The Science
Primary Reaction
lactose → lactic acid (via lactobacilli and streptococci)