بررسی اثر ضد کپکی جدایه های لاکتوباسیلوس پلانتاروم مراحل مختلف تولید پنیر لیقوان بر کپک پنیسیلیوم اکسپانسوم به عنوان شاخص فساد میکروبی آبمیوه

The objective of this experiment was to investigate the antimould effect of 19 Lactobacillus plantarum strains isolated from different production stages of Lighvan cheese (3, 8 and 8 strains from raw milk, curd and fresh cheese stages, respectively) a traditional raw milk cheese, on Penicillium expansum (PTCC 89046) as an indicator in fruit juice spoilage. This antimould spectrum was determined by agar spot and well diffusion method, followed by determination the influence of different technological or physico-chemical factors including temperature (80°C for 1 h, 100°C for 10 min, 100°C for 30 min and 121° C for 15 min) and pH( 2 to 7) and different dilution (Titre test) . Serial twofold dilutions were conducted to the CFE in order to assess of CFE Titre against mould indicator. Findings revealed that Lactobacillus plantarum strain C28 has the highest antimould properties in both antimicrobial methods (Agar Spot and Well Diffussion Assay) and antimould effect showed decreasing trend with pH increasing. In 121 ° C for 15 min, no antimould effect was observed. The Lactobacillus plantarum strain C28 showed the highest titre factor of 160 (AU / ml) . Finally, we can assume that these strains which isolated from different production stages of Lighvan cheese or their Cell Free Extract (CFE) can be used as biopreservative in food systems.