No important dierences were observed in the pH values of all the samples treated at 80 or 92C by microwaves and conventionally, measured throughout the 15 days of storage; the pH began to decrease after the 15th day. In a study on the eect of pasteurisation and storage conditions on the quality of milk, no pH changes were observed when milk was stored at 3C for 35 days (Cromie, Schmidt & Dommett, 1989).