Pasteurization efficiency of donor human milk processed by microwave heating

The main objective of this work was to verify the efficiency of batch microwave-assisted heating for donor human milk and assess the activity of alkaline phosphatase (ALP) and microbiological quality. Processing was conducted at different temperatures between (50 and 80) °C and times from (5–300) s in order to evaluate the suitability of ALP as a target for the microwave process of donor human milk. The thermal inactivation of ALP followed first-order kinetics with a z-value of 4.4 °C that indicates a strong dependency of ALP inactivation with temperature. The optimal conditions (60 °C for 30 s) were determined, based on ALP inactivation, and the microbiological quality of the processed donor human milk was evaluated. No pathogens (mesophilic bacteria, coliforms at 35 °C, Salmonella spp. and Staphylococcus spp.) were detected after microwave-assisted heating and this suggests that this technology can be applied to ensure adequate safety and quality in Human Milk Banks (HMBs).