The objective of this project was to identify a cost-effective and environmentally sustainable processing method for the valorization of acid whey that preserves the beneficial properties of the components originally found in the raw material, as well as to create functional prototype whey drink compositions and determine the safety and tolerability of the whey drink, including its impact on human metabolic health. To achieve the project's ultimate goal, the research and development work was systematically divided into five work packages, where activities took place in parallel to support the attainment of the final objective. Within the framework of Work Package I, the chemical and microbiological composition of raw acid whey and pre-treated whey was mapped through chemical and microbiological analyses. The chemical parameters generally coincided with data from scientific literature, except for certain differences in mineral content, which can be attributed to both the specific nature of the raw material and the technological processes used. Regarding microbiological indicators, raw whey contained relatively high concentrations of microorganisms, including psychrotrophic microorganisms. Lactic acid bacteria accounted for the majority of the microorganisms found in the raw whey. The research results revealed that raw whey should either be thermally treated or rapidly cooled to a low temperature to prevent the development of lactic acid bacteria and other microorganisms, as well as the spoilage processes they cause. Based on the data collected during the monitoring carried out within the project, a database was created, which allowed the results to serve as a basis for developing further whey processing stages.