Reducing the risk of spoilage caused by Bacillus cereus in cow's and goat's milk yogurt with berries puree

The objective of this study was to investigate the impact adding aronia (Aronia melenocarpa), raspberry (Rubus idaeus), and strawberry (Fragaria xananassa) in form 10% puree a mixture cow's goat's milk order reduce risk spoilage caused by activity Bacillus cereus yoghurt made from milk. During fermentation process (360 min.), changes water activity, pH, moisture content, bacterial growth curve were monitored. results showed decrease content. Adding yielded most significant for modification (0.971-0.868), pH (5.31-4.28), content (85.12-81.55 %), optical density (0.19-0.34). Also, investigation kinetics grows indicated that stationary phase reached at 360 minutes, resulting total population 5.5·1013 c.f.u./g. Microscopic examination revealed Gram-positive strains lactic acid bacteria, arranged chains varying lengths, an amount 139·102 Antimicrobial zone inhibition with diameter 18.5±0.1 mm yoghurt, 16.2±0.2 15.2±0.1 compared classic which 12.1±0.2 mm.