SWEETENED CONDENSED MiiK 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.—I‘inally, 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.—I.umps of varying denominations are 
not infrequently found in sweetened condensed milk. They maw 
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 1s 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- 
