Fermented milk products are produced from homogenised or pasteurized milk or cream with the help of starters containing lactic acid bacteria. Some of these products have been enriched with different types of dairy products (whey powder, milk powder, buttermilk powder) before fermentation.
The use of different starters in manufacturing various types of products gives each product a specific texture and a characteristic taste. Fermentation temperature and time vary by product.
In manufacturing kefir, sour milk, sour cream and fermented buttermilk, lower fermentation temperatures (24–30 °C) are used. The manufacturing of yogurt requires higher fermentation temperatures (38–42 °C). All fermented dairy products are cooled before packaging in order to hinder the growth of the lactic acid bacteria in the products.
The content of living lactic acid bacteria in fresh fermented dairy products should be ≥107 CFU/g. Fermented milk products should be stored at 2–6 °C.
Kefir is a fermented milk product that was traditionally made with kefir fungi. Today, a starter made from kefir fungi is used. In addition to lactic acid bacteria, the kefir microflora also contains yeasts. Yeasts give kefir its characteristic, slightly sharp taste and effervescent texture. The yeast content of kefir should be 104 CFU/g.
Besides lactic acid fermentation, some alcohol and CO2 are produced in kefir as a result of the effect of yeasts. Today, most kefir is produced with a 2.5% fat content.
Buttermilk is a liquid left behind after churning butter out of cream. Buttermilk may be marketed as a fresh or a fermented product, but the latter is more common. A mixture of buttermilk and skimmed milk is used as a raw material for making buttermilk to which mesophilic starter is added. Fermented buttermilk is a slightly sour and effervescent product, the fat content of which doesn’t exceed 0.5%.
Sour milk is a standardised fermented milk product. Mesophilic lactic acid bacteria are used for fermentation, and various fruit and berry ingredients may be added to the final product.
Sour cream is manufactured by adding mesophilic lactic acid bacteria to standardised cream. Sour creams with a 10% or 20% fat content are most common. Sour cream is a highly viscous and slightly sour dairy product.
Fermented Milk Products in Estonia
Watch a video about fermented milk products in Estonia. Mare Reiman, Tere AS.