March, 1936] Maintenance of Grade A Milk 11 



counts for these 31 dairies in relation to the inspector's scores, it shows very 

 little correlation between the bacteria counts and the scores. Apparently a 

 dairy with a low score was almost as likely to have bacteria counts under 

 10,000 as one with a high score. 



The score-card used by the Boston Board of Health is approved by the 

 U. S. Bureau of Animal Industry. A perfect score of 40 points is allowed 

 on equipment and one of 60 points on methods. In fixing the points allowed 

 under these two principal headings, the inspector is given considerable lee- 

 way. If the water supply was poor or if there was evidence of the presence 

 of dangerous disease in animals or attendants, the score would be 0. Fre- 

 quently an inspector had to score a dairy severely in order to have objection- 

 able features corrected. Under these various circumstances it is to be ex- 

 pected that the final scores would vary widely. However, it seems apparent 

 from this scatter diagram that the factors which may cause high bacteria 

 counts should be weighted and scored on a different basis. 



Principal Factors Causing High Counts 



A careful study was made of each Grade A producer's counts during the 

 three-year period. It frecjuently happened that a high count of 25,000 

 occurred along with three low ones so that the average for the 15-day period 

 was under 10,000, thereby allowing first premiums to be paid. Other pro- 

 ducers might have many high counts continuously for several pay periods 

 so that they got second or third premiums, or perhaps the average ran over 

 50,000 for the pay period so that no premiums were paid. 



The dairymen were naturally interested in knowing what caused these 

 high counts and how they could be controlled. Through personal contacts 

 with them in cooperation with the manager of Pattee Station a long list 

 of factors and causes was detected regarding the high counts. The fact 

 that on only six per cent of the farms some reason could not be found shows 

 how carefully the situation was studied. (See Table 4.) 



By far the greatest number of producers were having trouble in steril- 

 izing their equipment. Fifty-seven did not sterilize properly in 1931, twenty- 

 five in 1932, and twenty-nine in 1933. The equipment itself was the prin- 

 cipal factor contributing toward high bacterial growth. Other reasons men- 

 tioned were milking machine not washed thoroughly previous to steriliz- 

 ing, lack of the proper equipment to sterilize, old broken and porous rubber 

 in use on milking machine which was practically impossible to sterilize, the 

 use of old-fashioned eight-quart cans in coolings, which had rough seams 

 of solder and exposed wooden plugs, and milk cans which were dirty or 

 had broken seams. In all 38 per cent of the producers blamed their high 

 counts on improper sterilizing. 



On a seasonal basis, lack of sterilizing caused high counts for more pro- 

 ducers during the summer months than at any other time of the year. Dur- 

 ing July, August, and September over 52 per cent of them reported trouble 

 from this factor. More failed to steriHze properly during September than 

 any other month. The best record was made in December, when only two 

 producers experienced high counts from improper sterilizing. 



In making the survey of the 82 Grade A producers, information was 

 obtained as to their methods and practices in caring for the equipment and 

 handling the milk. After all, it is just as important to report the practices 

 which have worked out satisfactorily on the farm as it is to point out those 

 which have failed. 



