Fermented Dairy Items for Health Promotion!

Microorganisms introduced into a fermented product must be present in fermented beverages in an adequate number of living and active cells to reach the final day of shelf life. Among consumers in Poland, the most popular and produced in the largest quantities are the following milk drinks: yogurt, kefir, buttermilk, acidophilus milk, and other products containing probiotic microflora. However, the emergence of new strains of bacteria over the past 50 years has led to an increase in the fermentation of milk acids. Despite this, the production methods remain unchanged from a technological perspective. The main stage of production is the fermentation process, where liquid milk is converted into a thick, acidic product. The lactic acid bacteria use lactose as a substrate in this process, resulting in the production of lactic acid, which lowers the pH of the milk and alters the protein structure. The type of bacteria added to fermented milk products determines the basic properties of the final product. In Europe, fermented milk products are permitted for which one of two types of bacteria is used: bacteria of the genus Lactobacillus (the most commonly used are Lactobacillus delbrueckii ssp. bulgaricus, L. crispatus, L. gasseri, L. fermentum, L. acidophilus, L. Casei) or bacteria of the genus Bifidobacterium (from this group, B. bifidum, B. longum, B. breve, B. adolescentis, B. lactis are used).

Products that contain 3.5 g of fat per 100 g of product are classified as fatty. On the other hand, products with 1.8 g of fat per 100 g of product are considered semi-fat, while those containing less than 0.5 g/100 g of fat are labeled as lean. Dairy components such as skimmed milk, powdered milk, cream, casein, or non-dairy components, e.g., sugar, chocolate, or fruit, can be added to fermented products.

Milk forms the basis of dairy products subjected to fermentation and is responsible for their nutritional value. If these products contain additional substances such as chocolate, sugar, or fruit, they also influence the nutritional value of the fermented products. The principal milk carbohydrate is lactose – a disaccharide made up of glucose and galactose particles. A large portion of this sugar undergoes fermentation, and its deficiency in the product is compensated by the lactose content present in milk. In unsweetened items subjected to fermentation, there are also around 5 g of carbohydrates per 100 g of the product. In yogurts with sugar or fruit additives, their content ranges from 12.5 – 18 g per 100 g. The protein content in items subjected to fermentation ranges from 3.5 – 4 g/100 g product. Meanwhile, the calcium content typically exceeds 120 mg/100 g product. Items subjected to fermentation are also a source of B-group vitamins such as B2, B9, B12, fat-soluble vitamins such as A, D, E, K, and mineral components such as the already mentioned calcium, but also phosphorus, potassium, and magnesium.

Dairy products that undergo fermentation have a beneficial effect on health, mainly due to the presence of live bacterial cultures within them. Regular consumption of these products contributes to boosting immunity by stimulating the body's immune mechanisms. They activate macrophages to present B lymphocyte antigens and inhibit the release of IgA immunoglobulin. Additionally, they increase the number of leukocytes, lymphocytes, plasma cells, and natural killer cells (NK) present in the blood serum. The bacteria also increase the volume of food residues, stimulating intestinal movements, thereby reducing the risk of constipation. They also lower the risk of colon cancer. They play an important role in the treatment of food poisoning and diarrhea, as well as in the restoration of intestinal flora after antibiotic therapy. Products containing probiotic bacterial strains also have an anti-cancer effect, for example, through the binding of mutagens, removal of nitrates (III), inhibition of cancer cell growth, and inhibition of the activity of fecal enzymes. Some studies show that the consumption of fermented beverages lowers cholesterol levels in the blood, reducing the risk of atherosclerosis. Fermented dairy products can also help lower blood pressure by converting peptidases into antihypertensive tripeptidases. They can also be consumed by people with lactose intolerance, as lactic acid bacteria break down this sugar into simple sugars.