Thermal inactivation of phosphatase in raw whole milk was determined by the AOAC-V method. D-values in duplicate experiments at temperatures of 63.3, 66.1, 68.9, and 71.7°C were 332.0 and 338.0 s, 91.6 and 90.2 s, 31.4 and 27.6 s, and 9.9 and 8.9 s, respectively. The ZD-value was 5.39°C. Results confirmed phosphatase activity in milk heated at 71.7°C for 15 s and the need to heat raw whole milk for at least 19 s at 72.2°C to obtain a negative test by the AOAC-V.

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