Salima Varona Iglesias
Fraunhofer Institute for Interfacial Engineering and Biotechnology, Germany
Title: Continuous non-thermal high pressure process for skimmed raw milk stabilization
Biography
Biography: Salima Varona Iglesias
Abstract
Thermal pasteurization is the standard stabilization method used in raw milk, however alternative non-thermal methods are demanded not only to protect sensory and nutritional properties, but also for reducing energy and water consumptions. In the present study, the suitability of using the pressure change technology (PCT) which uses inert gases (N2 and Ar) for the treatment of milk was investigated. Performance trials were carried out on a continuous PCT system treating skimmed raw milk with an initial total bacterial plate count (TBPC) of 5.4 log CFU/ml at different operation conditions. TBPC and pH were analyzed before and directly treatment and variations were monitored during six days of cold storage (5-7°C). Results show that TBPC of the skimmed raw milk was reduced by 1.39 log direct after the PCT treatment and maintained during 6 days. The pH was monitored during the 6 days of storage shifting from 6.1 to 5.1. The TBPC in the PCT treated samples changed from 4.08 log (day 1) to 4.20 CFU/ml after 6 days of storage. In both of cases, microbial load remained below the minimum accepted microbial load level (4.47 log CFU/ml) established by the EC standards. It was concluded; that PCT treated skim milk can be stored for few days as an intermediate product in dairy plants or used for the production of cheese or other dairy products. This case study as well demonstrated that using the PCT technology energy and water consumptions can be reduced by up to 50% in comparison with classical pasteurization.