PRODUCTION" OF MILK OF LOW BACTERIAL CONTENT. 



Table 1. 



-Bacteria per cubic centimeter in dual samples of fresh milk produced 

 under conditions described in Experiment No. 1. 



Date. 



Sample 

 No. 



Open 

 pail. 



Small- 

 top pail. 



Date. 



Sample 

 No. 



Open 

 pail. 



Small- 

 top pail. 



1915. 



1 

 2 

 3 



4 

 5 

 G 

 7 

 8 

 9 



10 

 11 

 12 

 13 

 11 

 15 

 16 

 17 



14,000 

 170,000 

 125,000 

 280, 000 

 600, 000 





1915. 



Aug. 5, a. m 



Aug. 5, p. m 



Aug. 6, p. m 



Aug. 7, a. m 



Aug. 9, a. m 



Aug. 9, p. m 



18 

 19 



20 

 21 

 22 

 23 

 24 

 25 

 26 

 27 

 28 

 29 

 30 

 31 

 32 



600, 000 

 650, 000 

 400, 000 

 300, 000 



600,000 





45, 000 

 60, 000 

 150, 000 

 450, 000 

 200, 000 

 130, 000 

 160, 000 

 175, 000 

 200, 000 

 310, 000 

 750, 000 

 350, 000 

 750, 000 



550, 000 









250, 000 





400, 000 



July 27, a. m 



July 27, p. m 



July 28, a. m 



550,000 



500, 000 



240, 000 

 350, 000 

 390, 000 

 320, 000 

 500, 000 

 900,000 



500, 000 





350, 000 

 400, 000 

 900, 000 

 1,200,000 

 800,000 

 600,000 

 450, 000 

 700, 000 



450, 000 



Aug. 11, a. m 



300,000 





Aug. 11, p. m 



Aug. 12, a. m 



450, 000 



July 29, p. m 



July 30, a. m 



500,000 

 400, 000 



Aug. 13, a. m 



450, 000 







Aug. 13, p. m 



300, 000 





550,000 



Aug. 14, a. m 



500, 000 





400, 000 







600, 000 





497,653 



368,214 













Perhaps the most interesting point brought out by the results was 

 the relatively low bacterial count obtained in all samples. It is rea- 

 sonable to suppose that milk produced under such extremely filthy 

 conditions would contain millions of bacteria per cubic centimeter. 

 The figures indicate very clearly, however, that large numbers of 

 bacteria are not commonly found in fresh milk. Even when ex- 

 tremely high counts are obtained, they are probably attributable to 

 some other factor, such as growth or subsequent infection during the 

 various stages of handling. Throughout the experiments the milk 

 was examined before cooling, as it was the intention to avoid the 

 variable factor of contamination from unsterilized coolers. 



EXPERIMENT NO. 2 (COWS AND FLOOR DIRTY, MANURE REMOVED WEEKLY, 



UTENSILS STERILIZED). 



Having determined the number of bacteria in fresh milk produced 

 under extreme conditions of filth, where unsterilized utensils were 

 used, the next step was to use one factor which was considered of 

 utmost importance in preventing contamination, namely, sterilized 

 utensils. Samples of milk were taken from September 14 to October 

 7, 1915, under conditions as nearly identical as possible with those 

 of the previous experiment, with the exception that the cans and 

 pails were sterilized. 



By the use of sterilized utensils a remarkable decrease in the bac- 

 terial content of the milk was found. From the results of 36 sam- 

 ples shown in Table 2 it will be seen that the average count of milk 

 from open pails was 22,677 bacteria per cubic centimeter, compared 

 with 17,027 from small-top pails. Comparison with the results shown 

 in Table 1 is convincing proof of the value of sterilized utensils. It 

 should be remembered that the figures represent samples taken under 

 filthy conditions and that the only factor contributing to the differ- 

 ence in the bacterial count was the use of sterilized utensils. 



The range in the bacterial content of samples taken from the open 

 pail during the experiment was from 2,500 to 80,000, and in the sam- 

 189S9 — 18— Bull. 642 2 



