DAIRY FARMING DAIRYING. 



485 



sterilization, etr. IMethods of pasteurizing;: adajited to honu' us(^ arc (U-si rilnd and 

 suggestions given for j)asteurizing infants' food. The bulletin is sunnnarized at some 

 length. 



A study of the pasteurization of milk, H. Wkujmann {Mikh, /Ay., 30 [1001), 

 No. 27, ■}>}>. 417-410; Xo. 2S, pp. 48,3-4'S4)- — An experimental study of different sys- 

 tems and makes of api)aratus. 



Influence of pasteurization upon the properties of milk and. the processes 

 of butter making, R. 8teinkk [Milch. Zhj., 30 [1901), No. ^6, pp. 401-403; No. 

 ~.V, ]>. 4-^-'>) ■ — The author made a study of the effeet of pasteurizing upon the vis- 

 cosity and the specific gravity of milk, and also its effect upon the action of rennet. 

 Milk to l»e tested was divided into two portions, one left at room temperature for 3 

 hours and the other heated 15 minutes at 70° C. and ra]>idly cooled. 



It was found that pasteurizing lowered the viscosity of the milk. This result 

 seemed to depend somewhat upon tlie concentration, for when water was added to 

 replace evaporation the effect was lessened. The specific gravity was influenced but 

 little and that not i-onstantly. The coagulation was made with 0.1 cc. of rennet in 

 100 cc. of milk. In all cases the time of coagulation was increased with the pasteur- 

 ized milk.. The time varied with different milks, apparently depending upon the 

 composition. The completeness of the coagulation was also hindered l)y pasteur- 

 ization. The following table shows the effect of pasteurization ui)on duplicate sam- 

 ples of similar milk: 



Effect of pasleurizalion ujjon ro(ir/vlation. 



A study was also made of the influence of pasteurization upon butter making. In 

 this the fat content of the whole milk, skim milk, and buttermilk was determined 

 and the total fat of the cream and Imtter estimated. The cream from the sejjarator 

 was divided into two portions, one cooled to 10° and the other heated to 75° for 15 

 minutes and cooled. Both portions were kept in the usual manner for from 20 to 24 

 hours and (churned. From the results two points were clear: First, that the time of 

 churning was shorter with the pasteurized milk, and second, the fat content of the 

 buttermilk was lessened. Taking the average of 6 trials the buttermilk from the 

 unpasteurized milk contained 1.2297 i)er cent of fat, white that from the pasteurized 

 milk contained only 0.8819 per cent. The quality of the pasteurized Imtter was 

 ■higher than that of the unpasteurized, the former scoring an average f)f !»<).60, while 

 the latter averaged 9-1.91. The average duration of the time of churning with the 

 pasteurized cream was 7o minutes; with the unpasteurized, 92 minutes. 



Why cream tests vary [f 'reamer ij Jour., 11 [1901), So. 143, jip. n, 7, 30, 31). — 

 Statements from several creamery men as to the causes of the variations of the tests 

 of cream from farm hand separators. 



The mechanical introduction of water in butter, E. Hekgkani' [J'lih/ic Jlr.ullh, 

 14 [1901), No. 1, ]>p. lO-l.i). — The author discusses the adulteration of butter in 

 Great Britain by the addition of water. The amount which may l)e added by 

 mechanical means is stated to range l)etween 18 and 3(3 i)er cent. 



The manufacture of hard cheese from pasteurized milk, 11. Tii;.m.\.\.\ [Milch. 



