The Effect of Black Mulberry Vinegar and Freeze-Dried Postbiotic-Based Marination on Microbial Safety and Quality Parameters of Beef Steaks

Abstract

The study aimed to characterize black mulberry vinegar and the freeze-dried postbiotic of Lacticaseibacillus casei and to evaluate the effects of a 6-h marinating process on the physicochemical, microbiological, textural, and sensory properties of tenderloin. The bioactive compounds in the vinegar and postbiotics were determined. The minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and diameter of inhibition zones were determined against Escherichia coli O157:H7, Salmonella, and Listeria monocytogenes. In the meat experiment, tenderloins were marinated at 4 degrees C for 6 h in solutions of 100% vinegar (V), 5%, 10%, 15% postbiotic (P), and their combinations. The characterization results showed the presence of 8 organic acids, 22 polyphenols, and 79-83 volatile compounds in the vinegar and postbiotics. The postbiotic-vinegar formulation exhibited high antioxidant activity and strong in vitro antimicrobial effects. The V + 15% P group showed the highest diameter of inhibition zone (17.84 to 22.56 mm) against the tested pathogens. The use of marinade reduced Salmonella, E. coli O157:H7, and L. monocytogenes by between 0.90 and 3.22 log10 compared to the control (P < 0.05). The tenderloins marinated with vinegar and postbiotics were significantly softer and had lower pH, myofibrillar spaces, and cooking and drip loss (P < 0.05). The tenderloins marinated with vinegar had lower sensory scores, while those marinated with postbiotics had higher scores than the control group. In conclusion, the vinegar- and postbiotic-based marinade improved the microbiological and physicochemical quality as well as the textural properties of tenderloin, highlighting the potential of postbiotics as natural functional ingredients.