DAIRY FARMING DAIRYING. 79 



parative study made of the bacterial coutent of tlie ruilk and tlie scores of 34 

 commercial dairies as determined by the Cornell card, the official card ap- 

 proved by the Dairy Instructors' Association, and the New York City card, 

 indicate that no correlation whatever exists between the quality of the milk 

 so far as it could be determined by laboratory methods and the score as ex- 

 pressed by any one of the three cards. The apparent reason for this lack of 

 relationship is that a large number of the items included on the score card 

 have little or no effect upon the number of bacteria present in the milk, there 

 being too great emphasis placed upon unessential factors in the score cards, 

 with a consequent lessened emphasis upon the factors which actually do afCect 

 the milk. 



While not denying the value of dairy score cards, the author believes that the 

 results of this investigation show that present score cards can not be satis- 

 factorily used as a means of grading milk according to quality. 



Some variation was found in the relative position of the various dairies when 

 scored simultaneously with all of the cards. In general, however, the scores 

 secured by using the Cornell card were the most lenient, while those secured 

 by using the New York City card were the most severe. 



What causes contribute to the loss of the cream line on pasteurized milk 

 in bottles, C. H. Kilbourne (Cream, and Milk Plant Mo., 3 (1915), No. 8, pp. 

 11-20). — Because of complaints that the volume of cream on bottled pasteurized 

 milk was decreased and the distinctness of demarcation between the cream and 

 the milk injuriously affected, tests were made by the Board of Health of New 

 York City to determine the cause of these difficulties. 



The results indicate that when milk is cleaned by a centrifugal clarifier the 

 volume of cream in the milk is reduced from 2 to 3 per cent. It was evident 

 that the volume of cream in bottled milk is influenced by various factors, 

 among which are included the temperature to which the milk is heated, the 

 length of time for which milk is held at the high temperature, the temperature 

 of the heating medium with which the milk comes in contact during the heating 

 process, the clarification of the milk, the type of apparatus used in treating 

 the milk and the amount of agitation to which the milk is subjected, esiiecially 

 when hot. This last factor appears to be one of the most important. It is 

 believed that under the most favorable circumstances heating to 145° F. and 

 holding for 30 minutes may be done without any injurious effect upon the 

 cream line, but it has been deemed best to reduce the required temperature to 

 142° in order to allow for uncontrollable factors which may tend to offset the 

 volume of cream. -»«* 



Factors influencing the quality of milk for condensing purposes, W. A. 

 LiNKLATEB (Wusihington Sta., We.^t. Wash. 8ta. Mo. Bui., 2 (191Jf), No. 9, pp. 

 2-5). — From studies made of the station dairy herd fed rations consisting of 

 alfalfa hay and grain, supplemented by green oats and vetch, mangels, turnips, 

 kale, and corn silage, it was concluded that variations in the quality of the milk 

 were due to bacteria getting into the milk after it was drawn rather than to the 

 kind of feed used, provided this was of good quality. 



It was found that following rain, when the yard 'became muddy, the bacterial 

 count increased. The cows got their flanks and udders soiled with mud, and in 

 spite of careful wiping the quality of the milk was lowei-ed. Poorly washed and 

 unsterilized milk utensils were demonstrated to be a source of infection. The 

 bacterial count increased from two to three times in the course of three or four 

 hours even when the milk was aerated and cooled down to a temperature of 

 about 60° F. A lowering of the quality of the milk followed exposure to dust, 

 the drop in quality being especially marked on windy days, or when the feeding 

 of silage, straw, or hay was done at the time of milking. 



