DAlltV FAKMING DAIRYING. 675 



Of the spore-building forms tlio aorobiL- and the facultative anaerobic were 

 represented l>,v the hay and potato bacillus group and were present in fresh 

 milk only in small quantity and as a rule only in the spore form. In pasteur- 

 ized milk tlu'y ,i,'radually increased in number. The obligate anaeroldc and the 

 gas-imnlucing bacteria of the coli-aerogenes group were not abundant, but when 

 presei t they increased at all temperatures between ~> and ;^7°. With an increase 

 in temperature the same si)ecies of coccus forms continued to predominate. The 

 alkali-producing nonliquefying forms ajipeared able to thrive unhindered by 

 the lactic-acid forms. The liquefying short-rod forms were present in hirge 

 numl)ers excei)t at 5 to 7°. After the second day B. fliinrrsceiifi multiplied so 

 rapidly that on the fourteenth day it composed nearly half the bacterial flora. 



A bibliography is ajipended to the article. 



The effect of pasteurization upon the development of ammonia in milk, 

 W. G. Whitman and II. C. Sherman (Jour. Amrr. Chem. Soc, 30 (1908), No. 

 8, pp. J 288-1295). — The bacterial decomposition of proteins in milk was studied 

 by measuring the amount of ammonia produced. The methods of determining 

 the ammonia were those previously used (E. S. R., 16, p. 946; IS, p. 1077) for 

 examining fresh samples of milk. Ten samples of milk were obtained from 

 different dealers and each divided into three portions, of which the first was 

 untreated, the second pasteurized at 65°, and the third pasteurized at 85°. 



The average amount of ammonia found in the raw millc after 2 days was 

 0.005(>, after 4 days O.OOSl, after 7 days 0.(M)65 per cent. In the portion pasteur- 

 ized at 65° the average per cent of ammonia after 2 days was 0.0011, after 4 

 days 0.0057, and after 7 days 0.0065 per cent. In the portion pasteurized at 

 cS5° the results were 0.001, 0.0047, and 0.0116, respectively. There was a steady 

 increase in " cleavage annnonia " in all samples of raw milk during the first 10 

 days, l>ut practically no gain after that. The pasteurized milk, on the contrary, 

 showed little increase the first 10 days but after that the "cleavage ammonia" 

 increased rapidly. From the second to the seventh day of standing the acidity 

 and annnonia increased in about the same proportions. Pasteurization retarded 

 souring but favored the development of an offensive putrid odor and a bitter 

 taste. 



" Ammonia as a measure of the decomposition of proteins in milk appears to 

 be especially useful in samples which have been pasteurized at high tempera- 

 tures and in which the development of annnonia is continuous; in samples 

 whicli have- been pasteurized at low temperatures or not at all, the sanitary 

 significance of the annnonia determination is less certain, since the annnonia 

 content at any given time can not be assumed to be proportional to the extent to 

 which protein decomposition has taken place." 



Chemical evidence of peptonization in raw and pasteurized milk, Rachel 

 H. ToLWEM, and H. (\ Sherman (Jour. liiol. Chcm., 5 (1908), No. 2-3, pp. 

 2'i1-2'>1). — This study was undertaken to supplement that of ammonia content 

 note<l above. Nine samples of milk were mixed and divided into four portions. 

 One portion was untreated and the others pasteurized by heating for 20 minutes 

 at <!(), 70, and !K)°, respectively. The sanqdes were then cooled and allowed to 

 stand at room tenqierature. After 2 and 1 days they were tested for odor. 

 :nidity, and peptone. 



" The results of this investigation, together with that of the effect of pasteur- 

 ization upon the development of annnonia in milk, tend to enqthasize from the 

 standpoint of the sulise(|uent chemical changes the desirai>ility of low tem- 

 l»eratnres as reconniiendcd iiy IJosenau and others, in pasteurizing milk when 

 necessary as a safeguard against infectious diseases and the ob.jecfionaldeness 

 of ilepending u|iou |)asteurization as a pn'servative measure. The inq»ortance 

 of keeping milk cold and consuming it quickly are apparently not diminished 



