بررسي تاثير فرايندهاي خامه گيري ، باكتوفوگاسيون دو مرحله اي و پاستوريزاسيون در كاهش بار ميكروبي شير پنيرسازي

Study of cream separation, two-stage bactofugation and pasteurization effect on bacterial load reduction of cheese milk

In this research, during different seasons of a year, effect of cream separation, two-stage bactofugation and pasteurization were studied on cheese milk microbial load reduction in a cheese production line using ultrafiltration technology. Results showed that related to microbial load reduction, preheating of raw milk in regeneration section of pasteurizer; centrifugal force in cream separator and bactofuges and heat treatment during pasteurization have considerable effect and the efficiency of different unit operations is affected by months and seasons. In addition, in different months of year, microbial population of raw milk have considerable alterations. The higher milk supply during the summer in comparison of other seasons, and some other factors related to the milk collection are at the origin of this changes. The efficiency of different apparatus in term of microbial load reduction are: 20-70% for cream separator, 60-90% for first bactofuge, 55-85% for second bactofuge and 92-98% for pasterrizer.