🥣 Fermented milk products

Fermented milk products are foods made when helpful bacteria, and sometimes yeasts, ferment the lactose in milk. Fermented milk products are made when the microorganisms of a starter ferment the lactose in milk. Lactic acid bacteria turn it into lactic acid, the acidity rises and the proteins coagulate into a thick mass. The Codex Alimentarius standard defines fermented milk in exactly this way and requires the starter bacteria to stay alive and abundant until the end of the shelf life, unless the product was heat-treated after fermentation.

According to the FAO, there are about 400 names for fermented milk products in the world, although there are far fewer actual types. They are grouped by type of fermentation: lactic (yogurt, soured milk, ryazhenka, curd cheese, dahi), yeast-lactic, where yeasts join the bacteria (kefir, koumiss, shubat), and mould-lactic (for example, Finnish viili). Under the Codex, yogurt is made with a symbiotic starter of Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus.

Kefir is fermented with special “kefir grains” — little clumps of bacteria and yeasts; according to the FAO, in the Caucasus they were handed down from generation to generation as family wealth. Koumiss made from mare’s milk is called airag in Mongolia and is regarded as the national drink. Souring is one of the oldest ways of preserving milk, especially in hot climates.