The aim of the study was to use 3 monocultures of Bifidobacterium (Bifidobacterium animalis ssp. lactis AD600, Bifidobacterium animalis ssp. lactis BB-12, and Bifidobacterium longum AD50) in fermented goat milk to assess the microbial, physicochemical, rheological, and sensory quality of beverages during a 3-wk storage period at 5°C. The results indicated that selected bifidobacteria may be used for production of fermented goat milk because they comply with the minimum standards specified by the Food and Agriculture Organization of the United Nations and the World Health Organization during the entire period of storage. However, goat milk fermented by Bif. longum AD50 had less than 106 cfu/g after 21 d of storage. The acidity, acetaldehyde content, viscosity, and hardness of fermented goat milk beverages depended on the strain and the storage period. Sensory properties were similar and acceptable, with a tendency for the quality to be reduced with an extended storage time. Depending on the monoculture of bifidobacteria used to manufacture fermented goat milk, the product had a different pH value. Titratable acidity in all fermented goat milk increased significantly along with the time of storage. Our study has shown that monocultures of bifidobacteria had a significant effect on the content of acetaldehyde, but the lowest effect over the entire storage period was observed in goat milk fermented by Bif. animalis ssp. lactis BB-12. This sample also had the lowest viscosity values compared with other samples and the best organoleptic properties during a 3-wk storage period.

The valorization of food industry by-products is still a major challenge. Here, we report the production of acid whey fermented beverages stabilized with flaxseed gum (derived from oil industry by-product). Four variants of drinks were prepared: (1) fermented whey (W), (2) fermented whey with milk powder added (5% w/v) (WMP), (3) fermented whey with flaxseed gum added (0.5% w/v) (WFG1) and (4) fermented whey with flaxseed gum added (1.0 % w/v) (WFG2). The beverages were kept in refrigerated conditions (5 ± 1 °C) for 28 days. Alterations in lactic acid bacteria population, pH, titratable acidity, water activity, syneresis, viscosity, acetaldehyde content, color, consumer acceptance, bio-active compounds and antioxidant activity were identified. The findings revealed that flaxseed gum addition significantly enhanced bacteria survivability and improved the viscosity of acid whey at a level comparable with milk powder, meeting consumer acceptance criteria. The beverages were characterized by normative physicochemical properties and showed high antioxidant activity and free amino acids level. The use of valuable by-products from the dairy and oil industries opens up a promising route for the production of innovative beverages, which is in accordance with the principles of circular economy and the idea of zero waste.

The common occurrence of organochlorine compounds in the environment, food and human tissues may constitute a serious threat to human health. The method of gas chromatography-mass spectroscopy was used to determine the content of pesticides in 15 samples of raw cow's milk from different regions of Poland. The results revealed high levels of p,p′-DDE, p,p′-DDT, heptachlor and aldrin. The studied milk contained lindane in average concentrations within the maximum limits. Although in 20% of all samples tested, the concentration of lindane exceeded permissible limits, while in 15% of samples the content of Σ DDT was too high. But the average daily consumption of milk containing organochlorine pesticides poses no direct threat to human health, because daily intake (DI) for all compounds were below the acceptable daily intake (ADI). Attention should be paid to the exposure of consumers to pesticide residues from other dairy foods.