16 



BULLETIN 642, IT. S. DEPARTMENT OE AGBICULTTJEE. 



Table 4. — Bacteria per cubic centimeter in dual samples of fresh milk produced 

 under conditions as described in Experiment No. .). 





Sample 

 No. 



Udder and teats. 



Date. 



Sample 

 No. 



Udder and teats. 



Date. 



"Wasted. 



Not 

 washed. 



"Washed. 



Not 

 washed. 



1916. 

 Feb. 28, p. m 



1 



2 



3 



4 



5 



6 



7 



8 



9 



10 



11 



12 



13 



14 



15 



16 



17 



18 



19 



20 



21 



22 



23 



24 



25 



20 



27 



28 



29 



30 



31 



32 



33 



34 



35 



30 



1,600 



3,700 

 5,400 

 2,200 

 4, COO 

 3,300 

 1,130 

 2,270 

 1,900 

 2,700 



980 

 3,900 

 2,500 

 1,400 

 1,370 

 1,150 



830 

 1,480 



620 

 3,6C0 



910 

 1,920 



820 

 2,550 

 1,140 

 2,190 

 1,970 

 1,360 

 1,520 



820 



680 

 2,190 

 1,660 

 2,070 

 1,140 

 2,290 



1,800 

 9,900 

 3,600 

 6,500 

 6,300 

 4,700 

 2,250 

 5,300 

 3,100 

 6,600 

 1,520 



13,300 

 5,100 



20, 4C0 

 1,260 

 2,370 

 1,050 

 2,210 

 1,120 

 8,7C0 

 1,590 

 2,350 

 2,670 



14,800 

 1,090 

 2,110 

 2,680 

 2,040 

 1,510 

 3,070 

 2,390 

 3,410 

 3,240 

 6,C20 

 2,480 

 3,110 



1916. 



37 

 38 

 39 

 40 

 41 

 42 

 43 

 44 

 45 

 46 

 47 

 48 

 49 

 50 

 51 

 52 

 53 

 54 

 55 

 56 

 57 

 58 

 59 

 60 

 61 

 62 

 63 

 64 

 65 



810 

 1,350 

 1,360 

 2,410 

 1,350 

 2,740 

 1,530 

 2,9C0 

 2,300 

 2,600 

 3,9X0 

 1/800 

 4,200 

 1,5C0 

 4,700 

 1,6C0 

 2,300 

 3,400 

 1,400 

 2,2C0 

 1,9C0 

 2,9C0 



800 

 1,4C0 

 2,7C0 

 3,4C0 

 3,200 

 2, 1C0 

 2,400 



2 660 







4,800 

 2 970 



Feb. 29, p. m 









4 010 





Mar. 26, p. m 



4 200 





4^750 

 6 700 









Mar. 28, p. m. 



3 600 







3 200 







5*100 







3 500 







3 300 







6 900 







4 100 







3' 400 







7' 400 







4 100 







4' 700 







5 500 







5 300 







2 200 







7 300 







5 200 







3,300 







1,500 







9,400 







2,300 







3,900 







7,200 





Average of milk 









2,154 

 '739 







4,524 





Average of ud- 









757 















1,415 



3,767 









The interpretation of the average counts obtained from washed 

 and unwashed udders must receive special attention. The counts 

 as they stand show 2,154 bacteria per cubic centimeter from cows 

 with washed udders and 4,524 bacteria from those with unwashed 

 udders. It can be said that washing the udder reduced the bacterial 

 counts about 50 per cent, which agrees in a general way with the 

 results obtained by Stocking. 1 This assertion should not be made, 

 however, without taking into consideration the actual bacterial con- 

 tent of the milk. When the number of bacteria is small a 50 per cent 

 reduction indicates practically no difference in the quality of the milk, 

 as, for example, a count of 2,000 per cubic centimeter compared with 

 1,000. If, however, the counts were as high as 1,000,000 and 500,000, 

 respectively, in the two samples, the factor causing the difference 

 would still produce a 50 per cent reduction, but there would be a much 

 greater difference in the quality of the milk with the higher counts. 



The bacterial counts of the 65 samples in this experiment have 

 been plotted and are shown in figure 10, which brings out in a 

 striking manner the fact that milk from the washed- udders has 



1 See list of references at end of bulletin. 



