880 EXPERIMENT STATION EECORD. [Vol. 38 



An examination of 81 cans of milk at the farm ready for transportation to the 

 dairy, when all utensils had been carefully steamed, showed an average germ 

 content of 6,807 bacteria per cubic centimeter. A similar examination of the 

 milk in 117 cans from the same farms, when all utensils were similarly treated, 

 except that the steaming was omitted, showed an average germ content of 

 285,600 bacteria per cubic centimeter. 



When the bottle filler was carefully washed and steamed it exerted no ap- 

 preciable effect upon the germ content of the milk passing through it. When it 

 was similarly w-ashed, but not steamed, the germ content of the milk of the first 

 bottle was increased on the average by 96,900 bacteria per cubic centimeter. 

 The continued use of the bottle filler gradually washed the larger part of the 

 germ life from the machine. 



A study of the collective infiuence of all the utensils that normally come into 

 contact with the milk, both at the barn and at the dairy, showed that when all 

 the utensils were carefully steamed the germ content of the milk in the bottles 

 was about 4,566 bacteria per cubic centimeter. When similar conditions ob- 

 tained, except that tlie steaming of the utensils was omitted, the germ content 

 of the millc approximated 257,240 bacteria per cubic centimeter. 



Of all the various utensils coming into contact with the milk at the barn and 

 at the dairy, the clarifier and the bottle filler when unsteamed proved to be the 

 most prolific sources of contamination. The clarifier added an average of 141,340 

 bacteria per cubic centimeter to the milk passed through it, while the bottle-filler 

 tank and the four valves of the filler added appproximately 436,000 bacteria per 

 cubic centimeter to the same milk. 



Factors of im.portance in producing milk of low bacterial coiuit, C. L. 

 RoADHousE (California Sta. Circ. 119 (1911), pp. 11, figs. 6).— This circular 

 points out briefly the principal sources of microorganisms in milk, and explains 

 how the care of milk leads to a lower bacterial content. Specifications are given 

 for the construction of an inexpensive combination hot-water heater and steam 

 sterilizer for dairy utensils. 



The pasteurization of sour, farm-skimmed cream for butter making, O. F. 

 HuNziKEE, G. Spitzeb, H. C. Mills, H. B. Switzeb, et al. (Indiana Sta. Bui. 

 208 (1911), pp. 3-16). — The experiments here reported were undertaken to de- 

 termine (1) the effect of pasteurization of sour, farm-separator cream on the 

 flavor, keeping quality, and market value of butter; (2) the effect of different 

 processes of pasteurization on the bacterial count of cream and butter and on 

 the flavor and keeping quality of butter; (3) the effect of pasteurization on the 

 chemical properties of fresh and stored butter; (4) the causes underlying the 

 changes in the flavor of raw and pasteurized cream butter in storage. 



In each set of experiments about 1,600 lbs. of 80 to 40 per cent cream of 0.3 to 

 0.7 per cent acidity was used. This cream was divided into four churnings, as 

 follows: (1) Churned raw; (2) pasteurized at 145° F., holding for 20 minutes; 

 (3) pasteurized at 165° flash process; (4) pasteurized at 185° flash process. 

 Five-lb. cartons of the butter were held in cold storage at from to 20°, and 

 were scored when fresh and when 30, 60, and 90 days old. The average scores 

 of 204 churnings indicate that the butter from the raw cream possessed the 

 poorest keeping quality, scoring 3.03 points lower when fresh and 4.51 points 

 lower when 90 days old than the butter from cream pasteurized at 145° hold- 

 ing process, which scored highest when fresh and after storage. Butter from 

 cream pasteurized at 165 and 185° flash process had a pronounced oily flavor. 

 The flavor largely disappeared in storage, but flavors characteristic of storage 

 butter developed. 



On the basis of market conditions at the time of this study, the butter from 

 the pasteurized cream, averaged, after 30 days' storage, from 0.8 to 0.9 ct, in 



