Flash sterilization system using a high-pressure homogenizer

A newly developed system employing a new sterilizing method using a high-pr essure homogenizer demonstrated high efficiency of sterilization on milk in spite,of short heating time, compared with the conventional method as a pl ate heat exchanger system. Fundamentally based on utilization of energy con version from pressure energy to heat energy, this system is quite useful as the flash-heating and sterilizing system in the second heating stage, norm ally overheated by the conventional method. Theoretically in the case of wa ter the temperature raised is about 23 degrees C at 100 MPa. On the high-pr essure homogenizer, the sterilizing temperature was set to 120 similar to 1 40% at 80 similar to 90 MPa of homogenizer pressure. For testing sterilizat ion effects, two kinds of endospore forming bacteria were added to raw milk and healed up and sterilized by this system. Then the survival numbers of these bacteria after sterilization were counted, and these effects were est imated by calculating F values. In result the same effects on sterilization were gained for this system, compared with a plate heat exchanger system. However, flavor and color of the products from this system were superior to those from a plate heat exchanger system because of low heat damage. And a s the size of dispersed droplets was anti-proportional to the pressure of h omogenization, the fine droplets were gained much more by high pressure in this system. Even after two months storage at 5 degrees C, fat floating cau sed by droplet coagulation was hardly found in spite of lower viscosity.