The difference between yoghurt, soured milk and kefir

The wide range of available dairy products begs the question; what are the essential differences between yoghurt (probiotic yoghurt), soured milk and kefir. All these dairy products belong to the category of fermented milk, although they mainly differ in the microorganism types that cause fermentation and in the number of microorganisms present, which can also be 1:100 in the ratio of sour milk to kefir.

Both yoghurt and soured milk contain up to three bacteria, although the most prominent among the three is traditional kefir, as in addition to more than a hundred microorganisms, it also contains yeast. Kefir is considered to be the undisputed king of fermented dairy products.

There are three basic ways to prepare lactic acid products:

• natural acidification of milk, triggered by the presence of microorganisms present in the air and milk, especially in the summer;
• induced fermentation of milk in the industrial production of soured milk and yoghurt, triggered by different cultures e.g. Streptococcus lactis, Lactobacillus delbrückii spp. Bulgaricus and related lactic acid bacteria;
• fermentation of milk triggered by live kefir grains.

Soured milk is traditionally made from fresh raw milk, fermented in the presence of naturally occurring numerous and various bacteria in a warm environment. It is characterised by its mild taste. It is often produced from fresh milk that comes from the local cows or sheep, which is typical in the Southern Balkan countries.

Soured milk, similar to home-produced milk, is produced in dairy industrial plants by adding a culture of several types of lactic acid bacteria, the main one being Streptococcus lactis, to pasteurised milk.

Yoghurt (in Turkish yoghurut – curdled milk) is the most well-known and popular fermented dairy product. It is produced with the help of selected lactic acid bacteria.

Probiotic yoghurt has grown in popularity in recent years. The main difference between regular and probiotic yoghurts is mainly the bacteria that they contain. The probiotic cultures most commonly found in probiotic yoghurt are Lactobacillus acidophilus, Bifidobacterium and Lactobacillus casei, of which only one type is usually subsequently added to the yoghurt.

Kefir is one of the oldest types of fermented milk from the Caucasus. True kefir is prepared according to the old traditional procedure made from true kefir grains and only kefir prepared in this way has beneficial health effects. Of all fermented dairy products, kefir boasts the most diverse microflora of lactic acid microorganisms, beneficial to humans.

AFTER ALL, KEFIR IS THE OLDEST KNOWN PROBIOTIC, which, due to its foamy structure, pungent taste and velvety acidity, can be considered as a refreshing beverage. Kefir is produced without any additives when kefir grains are added to milk and release a substantial number of microorganisms into the milk. Each group of microorganisms has a specific function. Under the influence of live kefir culture (sponges – grains), a fermentation process is triggered in milk, which fundamentally changes the composition of the finished product compared to its basic raw material – milk.

As a source of food during the fermentation process, bacteria and yeasts utilise the basic constituents of milk, transforming them into simpler, more easily digestible substances. For example, the breakdown of milk sugar (lactose), which makes it possible for people who are lactose intolerant to consume traditional kefir, is fascinating.

It can be said that it is a miracle made possible by the diverse microflora of live kefir grains. Kefir contains dozens of different types of bacteria and yeasts that live in harmony and produce different enzymes, antioxidants, vitamins, antitumor substances, a wide array of antibodies, biological stimulants, various micro hormones and other metabolites. It is a so-called super food that aids digestion and the metabolism, and due to its high content of antioxidants, it can be found at the top of the list of protective foods that prevent aging and civilisation diseases. It acts on fats and sugars in the blood, on the digestive tract (gastric acid, heartburn, constipation, etc.), helps to detoxify the body, improves the body’s drug response and alleviates their side effects, prevents infections, inhibits the process of aging and sclerosis, improves reproductive function, increases immune function, facilitates calcium intake in the elderly, improves digestibility and metabolism of sugar, protein and fat, it is suitable for most diets (including weight loss), works protectively on breastfeeding mothers and their infants, etc. Kefir has a special place in the kitchen because it can be used in beverages, pastries, sauces, sweet and savoury side dishes and salad dressings.