The estimation of the total solids and solids-not-fat of milk from the density and fat content

Abstract

The accuracy of the method specified in B.S. 734:1937 for the estimation of the total solids and solids-not-fat contents of milk from the density and fat content has been assessed by direct comparisons with the gravimetric method. A total of 2425 samples of milk, mostly from single herds, were examined in five series over different years.The percentages of solids estimated by the density method were lower, by an average of 0·06, than those determined gravimetrically. To correct for this error, and to compensate for the lower, more accurate fat percentages arising from the recent reduction in the capacity of the Gerber milk pipette, it was proposed that the density formulae be modified to T=0·25D+l·22F+0·72 and S.N.F.=0·25D+0·22F+0·72.These formulae were adopted in October 1957 in an amendment to the B.S. 734 published in 1955.