March, 1936] 



Maintenance of Grade A Milk 



The best records in the control of quality in milk were made in Novem- 

 ber and December. During these months first premiums were obtained by 

 71 per cent of the producers in 1931, 82 per cent in 1932, and 87 per cent 

 in 1933. 



Attention is called to the fact that the producers made the poorest show- 

 ing throughout the entire year 1931. In fact, they did about as poorly in 

 the cold winter month of January as during the summer months. The num- 

 ber of Grade A producers who received first premiums improved in 1932, 

 following the testing work done by the Experiment Station. This work 

 started October 6, 1931, and continued into the winter. It was repeated 

 during July, August, and September of 1932. In all, 41 fall and winter 

 dairies were carefully studied and checked ; also 30 summer dairies. An 

 attempt was made to select producers who had excellent quality records 

 as well as those who were having trouble. They were well distributed 

 throughout the whole section. The effect of this work undoubtedly helped 

 the dairymen to locate their trouble. 



The average bacterial counts on the milk samples taken under fall-winter 

 and spring-summer conditions on the Grade A farms are given in Table 2. 

 The results on the first and second streams show the value of discarding 

 these where high quality milk is produced. The bacterial counts on these 

 streams were much higher when the cows were in the barn than when out- 

 doors. Some of the cows' samples averaged in this table were proven in the 

 laboratory to have garget. If the bacterial count of the milk in the cans 

 is taken as 100%, the P. M. samples under fall- winter conditions increased 

 only 8% by the next morning, while under spring-summer conditions the 

 increase was 20%, showing that the cooling job was not done so well during 

 the warm weather. 



Table 2 



Difference between the average bacterial counts on the milk samples taken 

 under FalUWinter and Spring-Summer conditions 



Milk Samples Taken 



Spring-Summer 

 . K^ 



Bacteria 

 per ml. 

 P. M. 



Bacteria 

 per ml. 

 A. M. 



First Streams 



Second streams 



Pails from cows 



Cans in evenings 



Cans before leaving farm. 

 Cans at station 



The average bacterial counts on the P.M. samples were lower when 

 delivered at the receiving station, under both fall-winter and spring-summer 

 conditions. This condition was due mainly to the fact that the counts on the 

 cans when filled were much lower on the P. M. samples than on the A. M. 

 samples, showing that the utensils were not cleaned and sterilized so thor- 

 oughly in the evening. The increase in the bacterial count during transpor- 

 tation was slightly higher under the fall-winter conditions. The main cause 

 for this was that the milk was on the road longer and in some cases was sev- 

 eral hours older when delivered. In a few cases the temperature increase 

 in this milk during transportation was several degrees, but in the majority 

 of cases this increase was not over 2''F. 



