Microwave heat treatment application to pasteurization of human milk

A prototype of microwave pasteurizer has been proposed as an alternative for holder pasteurization (HP) routinely used in Human Milk Bank (HMB), ensuring microbiological safety of human milk (HM). It was shown that the time of heat generation was about 15-16 min shorter by applying the microwave than in HP. Total inactivation of heat-sensitive bacteria Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Staphylococcus epidermidis, suspended in milk, occurred in the temperature 62-72 degrees C in HP. In the case of heat resistant enterococci the level of inactivation depended on the conditions of the process and the properties of the strains. The application of microwave heating allows to obtain lower D-value than those achieved during HP. The using of microwave heating at 62.5 or 66 degrees C for 5 or 3 min, respectively, allows to inactivation of HM microbiota. Appropriate microbiological quality of milk is critical for the effectiveness of the pasteurization process. Industrial relevance: Looking for new methods of donor human milk (HM) preservation is dictated by the necessity of providing microbiological safety and, at the same time, maintain its high nutritional and biological value. The holder pasteurization used in the Human Milk Banks (HMB) (heating at 62 degrees C for 30 min) leads to inactivation of all vegetative forms of microorganisms. Unfortunately, this method causes significant reduction of health benefitting properties of HM. The paper demonstrates the possibility of using the new microwave pasteurizer for preservation of HM, allowing for quick heating of milk to the appropriate temperature and maintaining it in these conditions for a required time. It was shown that the decimal reduction times (D) for strains inoculated to UHT or human milk are several times shorter by using microwave heating than in the commercial pasteurization method. The total inactivation of HM microbiota is obtained after heating at 62.5 and 66 degrees C for 5 and 3 min, respectively.