Effects of Mold-Inhibiting Lactic Acid Bacteria on the Storage Quality of Fresh Cheese

Fresh cheese is rich in nutrients but is highly susceptible to mold contamination, resulting in a short shelf life and poor long-term storage stability. This study investigated the effects of three lactic acid bacterial (LAB) strains with mold-inhibiting properties, Lactiplantibacillus plantarum HH-LP56 (L1), Lactobacillus acidophilus HH-LA26 (L2), and Limosilactobacillus reuteri PB-LR09, on the quality characteristics of fresh cheese during storage. The results indicated that compared with the nisin supplemented group and the control group without any preservative added, addition of any of the three antifungal strains significantly improved the quality characteristics of fresh cheese during storage. In terms of antibacterial properties, the LAB groups performed excellently. After 60 days of storage, the total colony counts in groups L1 and L2 were significantly lower than those in the L3, nisin, and control groups (P < 0.05), and the mold counts did not exceed the limit stipulated by the Chinese national standard (≤ 50 CFU/g). The mold count in group L1 remained within the limit after 90 days, whereas the mold counts in the L3, nisin, and control groups exceeded the limit after 60 days of storage. With regard to quality characteristic, the LAB groups showed brighter color (higher brightness value, lower redness and yellowness values), superior texture, and richer milky aroma. The abundance of volatile flavor compounds was evidently higher in the LAB groups than in the control group. In total, 66 volatile flavor compounds were detected in group L1, with a richer and mellower flavor. In conclusion, the three LAB strains exhibited stronger antifungal effects than did nisin, with L1 showing the best performance. These strains can effectively extend the shelf life of fresh cheese while maintaining its desirable flavor and texture.