

ANNUAL REPORT, 1934 37 



market for use in making ice cream in the freezing tray of the home refrigerator. 

 This project was organized with the purpose of studying ice creams frozen without 

 stirring, as well as the various commercial preparations now available for use in 

 ice cream of this type. Considerable progress has already been made in the study. 



A Study of the Changes that Occur in the Storage of Frozen Sweet Cream. 



(H. G. Lindquist.) Cans of raw and pasteurized cream of varying fat content 

 were frozen and stored at 0° to -10 C F. for a period of 4 to 6 months. The raw 

 cream developed more of the storage or tallowy flavor than did the pasteurized 

 cream. 



Subjecting cream to fast freezing conditions, such as freezing in a small ice 

 cream freezer with the beater removed, appeared to partially prevent the fat 

 from oiling off, when the cream was thawed after a storage period'of 4 months. 



Thawing cream slowly by immersing the cans in water at a temperature of less 

 than 90°F. did not prevent oiling off when the cream was later pasteurized. 



The work will be continued in an attempt to find a suitable means of preventing 

 the oiling off of the fat when stored frozen cream is thawed. 



A Study of the Comparative Efficiency of Electrically Operated Tanks versus 

 Ice in the Cooling of Milk. (J. H. Frandsen.) During the year a study has been 

 made of the comparative efficiency of a number of the newer electrically operated 

 cooling tanks on the market, and of milk temperatures as affected by the water 

 level in the cooling tank. 



Presumably to hold down expenses, there is a practice on certain dairy farms 

 where electric cooling units are used of not keeping the tank full of water when 

 it contains only a half-capacity load of milk cans. Thus, for example, if the 

 tank contains only the cans of evening milk and these cans are full, much of this 

 milk is left above the water line until such time as the cans with the morning milk 

 are placed in the tank next day. 



To obtain definite information as to just what happens regarding the rate of 

 cooling where some of the milk is above the water line, an experiment was planned 

 whereby the temperature and samples for bacterial analysis of milk in all cans 

 were carefully taken above the water line, at the water line, and near the bottom 

 of the cans, as well as of the ice water in which the cans were immersed. These 

 tests were made using a tank without agitator and also one with agitator, when 

 the tank contained plenty of ice. 



The results would indicate that the water in the tank should be as high as the 

 milk line. This can be accomplished by the addition of more water to make up 

 for the absence of some cans or by providing some arrangement whereby weighted 

 empty cans may be placed in the tank so as to raise the water line to the height 

 of the milk in the cans. 



The results of this investigation are published in Department of Dairy Industry 

 Circular No. 12, which contains graphic illustrations of the data gathered in 

 the experiment. 



A Study of the Possibilities of Milk, Cream, and Plastic Cream in the Develop- 

 ment of New Products such as Combinations with Honey, Fruits, and Flavors 

 of Various Kinds. (J. H. Frandsen and T. Marcus.) A few pieces of special equip- 

 ment which can now be secured make possible the skimming of a specially rich 

 sweet cream containing from 70 to 80 percent butter fat and generally known as 

 "Plastic Cream." This plastic cream can be used as a basis for many delicious 

 dairy spreads. Just now when dairy products are cheap and there is a surplus 

 on the market seems the time to give them a trial in the home. 



