## 3 Results and Discussion
These bacteria may have proteolytic and lipolytic abilities, which can affect the fatty acid profile of the samples tested. In a study by [PERSON] et al. [39], _M. luteus_ bacteria showed slow proteolytic activity compared to other bacteria, e.g., _B. cereus_, _P. aeruginosa_, and _S. marcescens_. In contrast, isolates of _B. cereus_, _M. luteus_, _P. aeruginosa_, _S. marcescens_, and _S. aureus_ showed lipolytic activity, except for _E. coli_. A  
Figure 2: Incidence of compounds in all tested samples. X-axis values are lipid numbers of fatty acids, as explained in Table 1.  
study by the [PERSON] et al. team [40] showed that numerous microbial isolates from raw milk, including bacteria but also yeast, produce extracellular enzymes that can cause spoilage problems in the dairy industry. Bacterial lipases are widely used in the food industry, especially dairy [41]. Numerous bacterial species can produce these enzymes, including _B. licheniformis, P. fluorescens_, and _Acinetobacter_ sp. AU07 [42; 43; 44]. Among psychotrophic bacteria that produce lipolytic enzymes, _Pseudomonas_ is the predominant genus among \(G(-)\) bacteria, while _Bacillus_ is the predominant \(G(+)\) genus [45]. Other types of psychotrophic bacteria that can also produce lipolytic enzymes are _Serratia, Hafnia, Microbacterium_, and _Enterobacter_[46]. Bacteria of the genus _Serratia_, present in cream fractions, can hydrolyze triacylglyceroll Sycerools to FFAs, leading to a change in their profile (Table 2), as confirmed in a study by [PERSON] et al. [47]. These enzymes can hydrolyze triacylglyceroll present in foods, generating FFAs responsible for unpleasant perceived flavors, e.g., rancid, buttery, but also pungent, bitter, soapy, or even astringent, flavor [35; 45]. A team of researchers, [PERSON] and [PERSON] [48], demonstrated that many lipolytic isolates belong to the genus _Pseudomonas_. In their study, more than 70% of _Pseudomonas_ isolates showed lipolytic activity. The secretion of extracellular lipases has been described for several _Pseudomonas_ species, such as _P. pseudocaligenes_ and _P. fluorescens_[49; 50]. Thus, the presence, as well as the proteolytic capacity, of some of the bacteria we identified could also affect the stability of fat emulsions, which post-mediately affected the composition of FFAs, as confirmed by GC-MS analyses (Table 1). Through advanced research, it was possible to precisely determine the fatty acid profile of cream, buttermilk fractions, and anhydrous milk fat samples. The results unequivocally demonstrated that the quality of the raw material directly impacts the quality of the final product. It was found that the distribution of fatty acids in cream samples, buttermilk fractions, and AMF is strongly dependent on the physicochemical parameters, as well as production and storage conditions. Furthermore, the presence of bacteria exhibiting lipolytic and proteolytic abilities can significantly influence the fatty acid profile by hydrolyzing fats and destabilizing emulsions. These bacteria, through their enzymatic activities, can lead to undesirable qualitative changes that directly affect the stability and nutritional value of dairy products. These findings underline the crucial importance of monitoring and controlling both raw material parameters and production processes to optimize the quality of the final products. Such an approach is essential for ensuring the highest health and nutritional standards in the dairy industry. The following supporting information can be downloaded at: [[https://www.mdpi.com/article/10.3390/app14146117/s1](https://www.mdpi.com/article/10.3390/app14146117/s1)]([https://www.mdpi.com/article/10.3390/app14146117/s1](https://www.mdpi.com/article/10.3390/app14146117/s1)), Table S1: Physicochemical parameters of the raw material for AMF production. Figure S1: Chromatograms obtained through GC-MS analysis for cream samples. ; Table S2. GC-MS analysis results for Cream_1. ; Table S3. GC-MS analysis results for Cream_2. ; Table S4. GC-MS analysis results for Cream_3. ; Figure S2.