56 



BULLETIN 642, U. S. DEPARTMENT OF AGRICULTURE. 



samples of milk produced under dirty conditions were held at 15.5° C. 

 (60° F.) and 21.1° C. (70° F.) and examined when fresh, and after 

 12, 24, and 48 hours. 



From Table 27 it will be seen that 16 samples of milk pro- 

 duced under clean conditions in sterilized utensils when fresh 

 averaged 3,243 bacteria per cubic centimeter. After 12 hours at 

 15.5° C. (60° F.) the average count was 4,056 and at 21.1° C. 

 (70° F.) 19,312 bacteria per cubic centimeter. This shows an 

 advantage, of holding at the lower temperature which is more valuable 

 when the milk is held for 24 hours, as the average count was then 

 123,'562 when held at 15.5° C. (60° F.) and 10,006,875 when held at 

 21.1° C. (70° F.). After 48 hours the average count at both temper- 

 atures was high, but the milk held at 15.5° C. (60° F.) was much 

 lower. 



The samples of milk produced under dirty conditions in unsterilized 

 utensils ranged from 10,900 to 2,210,000 when fresh and averaged 

 707,761 bacteria per cubic centimeter. This high initial average count 

 increased to 3.376.961 after 12 hours at 15.5° C. (60° F.) and to 

 6,608,846 after 12 hours at 21.1° C. (70° F.). The counts were, of 

 course, very high at later periods at both temperatures. 



Table 27. — Growth of bacteria in mill; when held at lo.5 c 



21.1° C. (70° F.). 



C. (60° F.) and 



MILK PRODUCED UNDER CLEAN CONDITIONS IN STERILIZED UTENSILS. 



Sample No. 



Eresh. 



Held at 15.5° C. (60° F.)f or— 



Held at 21.1° C. (70° F.) for— 



12 hours. 



24 hours. 



48 hours. 



12 hours. 



24 hours. 



48 hours. 



1 



1,800 

 1,£00 

 1,700 

 3,100 

 11,200 

 7,900 

 1,800 

 700 

 5,600 

 1,100 

 3,400 

 1,400 

 3,100 

 1,200 

 3,800 

 2,200 



2,300 

 2,000 

 1,100 

 1,800 

 7,300 

 8,700 

 2,100 

 1,700 

 1,900 

 3,100 

 5,100 

 18,300 

 2,200 

 2,000 

 3,000 

 2,300 



48,000 



56,000 



55,000 



54,000 



83,000 



51,000 



78,000 



28,000 



23,000 



74,000 



38,000 



810,000 



60,000 



261,000 



112,000 



146,000 



13,200,000 

 16,500,000 

 38,000,000 



8,100 

 23,100 

 13,600 

 29, 100 

 14, 700 

 37,000 

 2,300 

 6,800 

 25,200 



4,100,000 

 26, 200, 000 

 23,700.000 

 12, 400, 000 

 4,700,000 

 8,200,000 

 510,000 

 1,880,000 

 5.400 .000 



1,290,000,000 



860, 000, 000 



2,410,000,000 



2 



3 



4 





41,000,000 

 57,000,000 

 12, 600, 000 

 4,800,000 

 20,100,000 

 42,000,000 

 14,100,000 



1,340,000,000 



1,810,000,000 



81,000,000 



6 





8 



82,000.000 



2, 980, 000, 000 



128,000,000 



960,000;000 



9 



10 



19,500 i 30,600,000 

 13,200 i 10,200,000 

 58,000 ! 5,700,000 



4,100 i 4,100,000 

 32,500 j 4,920,000 



5,800 | 6,000,000 

 16,000 11, -500, 000 



11 



12 



13 



18,100,000 

 46,0O0;0O0 

 16,600,000 



1,390,000,000 

 6,400,000,000 

 6,460,000,000 



14 



15 



16 











Average. 



3,243 



4,056 123,562 



26,176,923 



19,312 



10,006,875 



2,014,692,307 



MILK PRODUCED UNDER DIRTY CONDITIONS IN UNSTERILIZED UTENSILS. 



1 10,900 



2 ! 1,520,000 



3 1,880,000 



4 1,030,000 



5 ! 2,210,000 



6 ' 1,810,000 



7 330,000 



S 159,000 



9 96,000 



10 37,000 



11 18,000 



12 12,000 



13 : 28,000 



Average. 707, 761 



15, .500 



8,600,000 



8,700,000 



5,400,000 



11,700,000 



1,930,000 



4,200,000 



1,210,000 



1,310,000 



560,0000 



180,000 



24,000 



71,000 



182,000 



148,000,000 



154,000,000 



22,900,000 



81,000,000 



68,000,000 



10,300,000 



22,600,000 



29,400,000 



43,800,000 



47,200,000 



1,480,000 



2,300,000 



3,376,961 | 48,550,923 



169,000,000 



840,000,000 



1,180,000,000 



28,000,000 

 164, 000, 000 



ii3,ooo;ooo 



110,000,000 



212,000,000 



100,000,000 



45,000,000 



58,000 



12,800,000 



17,600,000 



8,200,000 



13,700,000 



6,100,000 



10,200,000 



2,830,000 



10,400,000 



2,360,000 



1,370,000 



99,000 



198,000 



49,000,000 

 460,000,000 

 960,000,000 

 630,000,000 

 149,000,000 

 75,000,000 

 37,000,000 



114,000,000 

 26,000,000 

 96,000,000 

 32,000,000 

 35,000,000 



1.780,000,000 

 7,-500,000,000 

 460,000,000 

 620,000,000 

 540, 000, 000 

 1, 860, 000, 000 

 350,000,000 



1,840,000,000 

 1,-500,000,000 

 2,080,000,000 



296,100,000 6,608,846 I 221,916,666 j 1,853.000,000 



