482 EXPERIMENT STATION RECORD. [Vol.35 



records of the Holstein-Friesian Association comparing the reliability of seven- 

 day and yearly tests, the author found that in general the yearly production 

 varied with the record for seven days, but not in the same proportion. For 

 instance, the cows yielding from 10 to 12 lbs. of fat in seven days gave on the 

 average 423.71 lbs. in 365 days, while cows yielding twice as much in seven 

 days gave only about one-half more in the course of a year. This indicates 

 that the cows which produce the best during the first few weeks do not hold 

 up so well later as do those which produce less during the early part of their 

 lactation period. It appears that the higher the seven-day record the greater 

 the variation in the 365-day test and the less accurate the seven-day test be- 

 comes as an indicator of the true production. 



Influence of temperature on the proteolytic activity of lactic ferments, 

 C. GoBiNi (Atti R. Acad. Lincei, Rend. CI. Sci. Fis., Mat. e Nat., 5. ser,, 24 

 (1915), II, No. 8, pp. 369-376; abs. in Internat. Inst. Agr. [Rome], Intemat. 

 Rev. Sci. and Pract. Agr., 7 (1916), No. 1, p. 143). — The author has already 

 pointed out (E. S. R., 34, p. 76) a difference in the organoleptic properties of 

 peptonized whey produced by the same lactic ferment but developed at different 

 temperatures. This difference led to the presumption of differences in the 

 products of caseolysis. 



The present investigations are a new analytic contribution to the demon- 

 stration already given by him as to the favorable influence exerted by low 

 temperatiu'es on the proteolytic activity of milk ferments. They further indi- 

 cate that the lactic ferments should be especially studied in cultures kept at 

 low temperatures. The number of lacto-proteolytic ferments capable of pep- 

 tonizing casein in an acid medium is enlarged, and it is concluded that the 

 optimum temperature is not the same for all the functions of a given micro- 

 organism. 



The proteolytic indexes have been collected by the author in a table, and 

 show the possibility of verifj'ing, also analytically, not only the quantitative 

 differences but also the qualitative differences in the proteolytic products of 

 lactic ferments according to the temperature. 



In the explanation of the greater caseolytic activity at low temperatures it 

 must be considered that at this temperature the lactic ferments attack lactose 

 more slowly. The milk attains later than at high temperatures a degree of 

 acidity capable of attenuating and stopping the development of the bacteria, 

 which thus can continue for a greater length of time to attack casein. 



Experiments in Sweden on the prolonged pasteurization of milk, G. 

 Babthei. (K. Landtbr. Akad. Handl. och Tidskr., 54 (1195), No. 7, pp. 610-648, 

 figs. 2; abs. in Internat. Inst. Agr. [Rome], Intemat. Rev. Sci. and Pract. Agr., 

 7 (1915), No. 1, pp. 143-I46). — Trials with the "holder" process of pasteurizing 

 conducted in Sweden have proved very satisfactory. It was found that milk 

 pasteurized for from 20 to 30 minutes at 145° F. has no "cooked" taste, 

 although this becomes noticeable at 149°. The cream also rises as readily in 

 milk pasteurized at 145° as in unheated milk, but after pasteurizing at 149° 

 it rises more slowly. Heating to 145° does not affect the protein or the soluble 

 phosphates, but here again the influence of a temperature of 149° begins to 

 make itself felt. The enzyms remain intact at 145° with the exception of 

 amylase, which is destroyed at a relatively low temperature. 



The experiments showed that pasteurized milk keeps from one to two days 

 longer than ordinary milk, according to the temperature at which it is kept. 

 The effect of pasteurization in destroying bacteria is also very satisfactory. 

 When the milk after being heated is reinfected by the ordinary lactic fer- 

 ments it becomes acid in the usual way, but naturally more slowly than un- 

 pasteurized milk. 



