Evaluation of the use of Lactobacillus plantarum and plantarsin in the preservation of lactic cheese

In this study, the role of bacteriocin produced by Lactobacillus plantarum TA013 (Plantarsin which has the most effect against Listeria monocytogenes) in the persistence of lactic cheese (LCh) was investigated. Groups: 1) LCh without probiotic bacteria and bacteriocin as a control 2) Probiotic LCh containing L. plantarum 3) LCh containing Plantarsin and 4 (LCh containing Nisin were considered. Physicochemical and microbiological properties of cheese in each treatment were determined in terms of pH, dry matter, fat, protein, salt, aflatoxin M1, fatty acid profile, and the growth inhibition of L. monocytogenes during 60 days storage in the refrigerator. Statistical analysis of this design was performed in a completely randomized design. The results showed that the reduction of L. monocytogenes in the treatment of LCh containing nisin in comparison with the control group was 3.05 Log(CFU/g), which was significantly different from the control group. in other treatments containing probiotics and Plantarisin, the rate of reduction of this pathogen compared to the control treatment was 2.76 and 1.79 Log(CFU/g) respectively, but no significant difference was observed between the two samples. Also, the survival rate of probiotics at the end of storage was 107 CFU/ g in the refrigerator and only two Log(CFU/g) were reduced. The results showed that cheese containing probiotics had superior properties over other treatments. Therefore, environmental conditions such as pasteurization are not sufficient to completely eliminate L. monocytogenes in lactic cheese, and it is necessary to use natural additives to create favorable conditions in different stages of production and storage.