
UNITED STATES DEPARTMENT OF AGRICULTURE 
In Cooperation with the 
Minnesota State Board of Health 
DEPARTMENT BULLETIN No. 1344 
Washington, D. C. 
July, 1925 
EFFECT OF VARIOUS FACTORS ON THE CREAMING ABILITY OF 
MARKET MILK 
By H. A. "Whittaker, R. W. Archibald, and L. Shere, of the Division of 
Sanitation, Minnesota State Board of Health, and C. E. Clement, Bureau of 
Dairying 
CONTENTS 
Page 
Reasons for investigation 1 
Methods used 3 
Effect of pasteurizing market milk__ 3 
Effect, of heating milk to various 
temperatures - 4 
Effect of heating and holding milk 
for 30 minutes at various tempera- 
tures at pasteurizing plants 5 
Effect of pasteurizing fresh milk 7 
Effect of pasteurizing old milk 7 
Effect of partially cooling pasteurized 
milk in vat or tank 9 
Effect of the temperature to which 
milk is cooled after pasteurization_ 10 
Effect of storage temperature 11 
Page 
Rapidity of creaming of raw and 
pasteurized milk 13 
Effect of age and recreaming of raw 
milk 14 
Effect of recreaming pasteurized milk. 15 
Effect of pumping milk 16. 
Effect of holding milk and of agitat- 
ing it at various temperatures be- 
fore and after pasteurization 18 
Effect of clarifying raw milk 21 
Effect of filtering milk 21 
Influence of various shapes of milk 
bottles on depth of cream layer__ 22 
Summary and conclusions 23 
REASONS FOR INVESTIGATION 
Two important qualities of market milk are safety and richness. 
Most consumers are not in a position to determine with any degree 
of accuracy the safety of the milk which they receive, but depend 
upon the health authorities to provide protection. The richness is 
judged by the housewife almost wholly by the amount of cream that 
can be seen at the top of the bottle, and not by the actual butterfat 
content as determined b} 7 the Babcock test. 
In the pasteurization of milk some difficulty has been experienced 
with variations in the depth of the cream layer. The consumers 
who observe this often believe they are receiving milk below the 
legal requirement in butterfat. A uniform and satisfactory cream 
layer on pasteurized milk is considered very important by health 
officials, because it is difficult to induce the public to purchase any 
grade of milk which does not show a satisfactory cream layer. More- 
over, on account of the keen competition that exists among milk 
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