SWEETENED CoNDENSED Mink DEFEctTS 241 
observed buttons on condensed milk held at 68 degrees I’. or 
below. These temperature limits are not corroborated by exper- 
iments by Hunziker, nor by the experience of the manufacturer. 
Tn commercial! manufacture, the storage of sweetened condensed 
milk at 68 degrees F. will show copious button formation, if such 
milk contains button-forming spores. Reasonably sure preven- 
tion of buttons may be secured by holding the sweetened con- 
densed milk at about 50 devrees F. or below. 
Exclusion of Oxygen.—Molds need air for their life and 
growth. They cannot develop in the absence of oxygen. Accord- 
Fig. 83. Fig. 84. 
Button development under Absence of buttons in 20-inch 
atmosperic pressure vacuum 
Courtesy of L. A. Rogers, U. S. Dairy Division 
ingly Rogers et al., by careful experimenting, found that by seal- 
ing the cans under a vacuum of 20 inches or more, button-for- 
mation in condensed milk contaminated with button-forming 
molds could be entirely prevented. 
It is probable that a similar effect, if practicable, could be 
accomplished also by charging the cans with an inert gas to the 
exclusion of atmospheric oxygen. 
