CONDENSED MI^K DEFECTS 233 



steam pressure in the jacket and coils, not to exceed five pounds 

 of pressure, and the milk should be drawn from the pan at..once_ 

 after condensation is completed. The superheating to which 

 the condensed milk is subjected in the pan, when finishing with 

 a high steam pressure in jacket and coils, or when the milk is 

 not drawn from the pan promptly when the vacuum pump is 

 stopped, or when an effort is made to condense to a very high 

 degree of concentration, is almost sure to cause the finished 

 product to spontaneously thicken with age and this tendency 

 is especially pronounced in the spring and early summer. 



Effect of Age on Thickening. Finally, all sweetened con- 

 densed milk has a tendency to thicken with age. Exposure to 

 high storage temperature (summer heat) hastens this action. 

 The rapidity of thickening in storage increases with the increase 

 in temperature. This tendency is very much reduced, therefore, 

 by protecting the goods from high temperatures and by storing 

 them below 60 degrees F. (See Chapter XVII on "Storage," page 

 191.) 



Lumpy Sweetened Condensed Milk. 



General Description. Lumps of varying denominations are 

 not infrequently found in sweetened condensed milk. They ma^ 

 be soft and permeate the contents of the can throughout, or may 

 appear especially in the form of a "smear" along the seams of 

 the can ; or again, they may float on the surface, in which case 

 they are usually hard and cheesy, and either white or yellow in 

 color. Their presence gives the contents of the can an unsightly 

 appearance at best, and in many cases, they spoil its flavor. 

 They naturally suggest to the consumer that something is wrong 

 with the condensed milk, and cause him to reject the whole 

 package. 



Causes and Prevention. The chief causes of lumpy con- 

 densed milk are: poor quality of fresh milk, unclean pipes in fac- 

 tory, milk from fresh cows, acid flux in tin cans, and unclean 

 and contaminated tin cans. 



Poor Quality of Fresh Milk and Unclean Factory Condi- 

 tions. Upon opening the can of condensed milk, even shortly 

 after it is filled, the lid is covered with large and small lumps and 

 specks sticking to the tin, presenting a very uninviting appear- 



