572 EXPERIMENT STATION EECOED. [Vol.35 



with the exception of one cow which reacted to the tuberculin test in April, 1914. 

 She had shown no reaction in two previous tests. The hair of the animals kept 

 outside was longer and coarser the first two winters. The third winter this was 

 noticeable in only one animal. 



Studies on the market milk of Iowa, B. W. Hammek and A. J. Hauser 

 (Iowa Sta. Bui. 164 U916), pp. 311-S80).— In these studies samples of milk, 

 cream, both table and whipping, and buttermilk were examined. The milk and 

 cream samples were scored according to the score cards adopted by the U. S. 

 Department of Agriculture, while the whipping cream was scored according to 

 the cream score card, with the exception that 30 per cent fat was considered 

 perfect and one point was deducted for each half per cent below this. The 

 buttermilk was examined for flavor, fat, and acidity only. The samples were 

 collected in twelve cities of the State of various sizes. 



It was found that some of the market milk and cream of Iowa contains ex- 

 cessive numbers of bacteria. In some cities the average bacterial content of the 

 pasteurized product exceeds that of the raw, although most frequently that of 

 the raw is the greater. Some of the milk and cream sold is very poor in flavor, 

 while some is very satisfactory. Only a small percentage of the samples ex- 

 amined were low in the amount of fat or solids-not-fat. Large amounts of sedi- 

 ment are not uncommon, while some samples show only insignificant amounts of 

 sediment. Excessive amounts of acid are sometimes found in both milk and 

 cream. From the results of the investigation it is concluded that the presence 

 of colon bacteria is a rather unsatisfactory basis for judging the sanitary quality 

 of a sample of milk or cream. 



A considerable amount of bulk milk is still sold in Iowa. Quart and pint 

 bottles of milk and half-pint bottles of cream commonly showed considerable 

 variations in the amounts of material contained. It is deemed reasonable when 

 buying quarts to expect an amount not over 2 per cent low, when buying pints 

 to expect an amount not over 3 per cent low, and when buying half pints to 

 expect an amount not over 4 per cent low. 



A proposed score card for bacteria in pasteurized milk is given. 



A study of the manufacture of dairy butter, E. L. Anthony (Pennsylvania 

 Sta. Rpt. 1914, PP- 163-173, pis. 8). — An experiiuent was conducted to deter- 

 mine the variations between the different styles of common farm churns as 

 to the percentage of moisture and salt left in the finished butter, as well as 

 the length of time of churning, the percentage of fot left in the buttermilk, 

 and the average rise of temperature of the buttermilk during churning. The 

 types of churn used were a 15-gal. barrel churn, 12-gal. swing churn, and a 

 combined churn and worker. The average moisture content of the butter from 

 the respective churns was 12.39, 13.5, and 13.6 per cent ; the average salt con- 

 tent, 4, 3.8, and 2.45 per cent; the time required for churning, 40, 47, and 29 

 minutes ; the rise of the temperature in churning, 6.3, 7, and 5° F. ; and the 

 average fat content of the buttermilk, 0.19, 0.229, and 0.18 per cent. 



The results of further studies indicate that by properly regulating the churn- 

 ing factors the percentage of moisture can be materially raised without affect- 

 ing the uniformity. In order to secure a high moisture content it is found 

 better to stop churning while the butter is still in small granules. The studies 

 also showed that with the common hand worker moisture is generally lost 

 as the working progresses, while by working the butter in the combined churn 

 the moisture content increases after a certain amount of working. 



Overripened cream did not produce butter of so good quality as cream 

 that was less ripe. In view of those studies it is recommended that cream be 

 ripened to not more than 0.5 per cent acid, and that as low as from 0.3 to 0.4 

 per cent is advisable under average farm conditions. Three methods (a) 



