Go to our new-look site, it combines the Biotechnology and Science Learning Hubs with a new look and new functionality. This is our legacy site and is no longer maintained.

Skip to page content

Site navigation

Lactic acid fermentation to separate the casein in milk

Fermentation is a process that some bacteria use to get energy from sugar. The energy is used by the bacteria to grow and multiply. The sugar is broken down, and lactic acid is produced as a by-product.

Lactic acid fermentation in milk gives casein. Specific bacteria (e.g. Streptococcus thermophiles, Lactobacillus acidophilis and Lactobacillus bulgaricus) carry out lactic acid fermentation in milk.

The lactic acid that is produced as a by-product makes the milk more acidic. Casein proteins (curds) separate from the milk under these conditions.

Yoghurt is an example of a product that is made using lactic acid fermentation.


Return to top