Dairy Chemistry And Biochemistry

246 DAIRY CHEMISTRY AND BIOCHEMISTRY

seasonal trend; the pH of colostrum is about 6 but increases to the normal

value of about 6.6-6.7 shortly after parturition and changes little until late

lactation, when the pH raises to as high as 7.2, i.e. approaches that of blood

(pH 7.4) due to degeneration of the mammary cell membrane. The pH of

milk also increases during mastitic infection (e.g. 6.8-6.9), due to the influx

of constituents from blood.

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Figure 5.5 Correlations between the concentration of sodium and potassium (a) and sodium
and chloride (b) in bovine milk.