1916] DAIRY FARMING DAIRYING- 875 



flavor was uniformly clean, while the uncooled cream in most cases had an 

 unpalatable flavor. Bacteriological analyses of the cream showed that the 

 average reduction of micro-organisms ascribed to the use of cooling tanks in 

 this experiment was 35 per cent of the total bacterial content, 35.8 per cent 

 of the lactic acid bacteria, 72 per cent of the liquefiers, and 75 per cent of the 

 undesirable yeast and molds. In fermentation tests the cooled creum produced 

 a solid curd with a sharp separation of a clean whey. The majority of the 

 fermentation tests from the uncooled cream showed a gassy curd and in some 

 cases the curd underwent decomposition. 



Analyses of all the experimental butter for moisture, salt, and curd showed 

 average percentages about the same for each set of butter. Bacteriological 

 analyses of samples of butter from each of the experimental churnings showed 

 the following reductions ascribed to the use of the cooling tank. Total bacteria 

 58.6 per cent, acidifiers 60.2 per cent, liquefiers 81.9 per cent, and yeast and 

 molds 87.4 per cent. The average score of the butter made from the uncooled 

 cream was 88.98 at the station, and two weeks later at New York 87.09, and 

 for the butter made from the cooled cream 91.63 at the station, and 89.7 at New 

 York. With one exception the cooled-cream butter scored uniformly higher 

 than the uncooled-cream butter, both at the station and at New York. On the 

 open market in New York the price received for the cooled-cream butter was 

 24.88 cts. per pound, and for the uncooled-cream butter 23.94 cts. per pound. 



The bulletin points out the essential features of satisfactory cream cooling 

 tanks, gives notes on the use of springs and wells for cooling cream, and de- 

 scribes several types of homemade and commercial cooling tanks. 



Progressive oxidation of cold-storage butter, D. C. Dyer (U. S. Dept. Agr., 

 Jour. Agr. Research, 6 (1916), No. 24, pp. 927-952, pi. 1, fig. l).—ln preliminary 

 work in this investigation, which was conducted in the Dairy Division of the 

 Bureau of Animal Industry, the attempt was made to determine whether the 

 undesirable flavors of storage butter arise from a decomposition occurring in 

 the fat itself or in some one or more of the other components entering into the 

 composition of the whole product. Examination of the air inclosed within 

 packages of butter differently prepared and in butter fat alone was made with 

 a specially designed gas apparatus which is illustrated and its manipulation 

 described. 



Very little alteration was found to occur in the composition of the air in- 

 closed in sweet cream butter made from cream having an acidity (calculated 

 as lactic acid) of 0.11 per cent when it was kept for about six months at a 

 temperature of 0° F. A perceptible change in composition of the inclosed 

 air was found when the butter was kept at a temperature of 32° and a very 

 noticeable change when it was kept at room temperature. The sample of 

 butter used, which contained a considerable number of bacteria, scored 92 when 

 made, 91 at the end of three months, and 90 at six months when stored at 0°. 

 At no time was there a trace of undesirable flavor. 



An analysis was made of air extracted from butter made from sweet cream 

 churned immediately after the addition of 15 per cent of a commercial starter. 

 At the time of churning this cream had an acidity of 0.25 per cent. The butter 

 made from this cream showed, so far as the composition of the air inclosed in 

 it was concerned, a comparatively slight variation from that observed in the 

 previous case of sweet-cream butter, when both samples were stored at a 

 temperature of 0°. This butter scored 92 when made and 89 after 6.5 months, 

 with no variation in flavor. Butter was also made from sweet cream churned 

 immediately after the addition of lactic acid. The acidity of this cream was 

 0.71 per cent. On analysis the air extracted from a sample of this butter 

 showed a pronounced decrease in the oxygen and carbon-dioxid content, even 



