## 1 Introduction
In the study of [PERSON] and [PERSON], the acid whey addition decreased the pH of dry-fermented nitrite-free beef sausage, which contributed to the microbiological safety of sausages [15]. Amino acids contained in acid whey, such as methionine and cysteine, have anti-cancer effects [21; 22]. The whey-based fermented food products are considered to provide positive immunomodulation in human health [23]. Vinegar has been commonly used for centuries as a food preservative [24]. Vinegar from natural fermentation is characterized by a high content of nutrients and bioactiveingredients, and has antioxidant effects [25]. It can be used in the technological processing of meat and has a positive impact on sensory properties, color, tenderness, microbiological safety, and the shelf life of meat products [26]. [PERSON] et al. (2023) detected 64 volatile flavor components during vinegar fermentation [27]. Naturally fermented apple vinegar is used in the technological processing of meat. Due to bioactive components (organic acid, polyphenols, vitamins, minerals), vinegar can be considered as a potential postbiotic that can support LAB growth. Two major groups of apple vinegar bacteria are acetic acid and lactic acid bacteria [28; 29; 30]. Acetic and lactic acid are two prominent organic acids of vinegar. They can lower the pH of fermented food matrices [27]. Antimicrobial compounds produced by acetic acid and LAB along with organic acids and phenolic and flavonoid compounds have antimicrobial activity that ensure the microbiological safety of marinated food [31]. Acid vinegar limits the development of unfavorable microbiota, including _Listeria monocytogenes_, _Staphylococcus aureus_, _Salmonella Typhimuriumium_, and _Escherichia coli_, _Bacillus cereus_, _Bacillus subtilis_, and _Enterococcus faecalis_[31; 32]. Additionally, the biological ingredients of fruit vinegar contribute to the health-promoting effect of meat products on the human body [33; 34; 35]. The application of natural preservatives enables the replacement or reduces the use of synthetic preservatives, resulting in positive effects that are appreciated and accepted by customers [36]. In meat processing, nitrate and nitrite commonly inhibit the growth of microorganisms, delay rancidity, and produce a pinkish-red colorand improveflavor. However, consuming processed meat cured with nitrate and nitrite involves serious health risks [37]. Nitrite-cured meat is regarded as a Group 1 carcinogen by IARC [38]. Thus, effective methods for replacing nitrite or nitrate in processed meat are needed. The attractiveness of fermented meat products for consumers and the food industry can be achieved through reducing or replacing nitrite; unique sensory qualities and the potential health-promoting effect of LAB can be increased [7; 39; 40]. Thus, this study aimed to evaluate the effect of using acid whey or apple vinegar as natural alternative additives in raw fermented beef hams. The idea was to use natural ingredients instead of chemical additives in innovative raw fermented beef hams without adding curing salt. Specifically, this study focused on evaluating the effect of the proposed natural marination process on the physicochemical, microbiological quality, and volatile and sensory profiles of the raw fermented beef hams.