BUTTER DEFECTS 475 



Proper pasteurization materially minimizes the tendency of 

 butter to become moldy. It is destructive to the majority of the 

 species of molds usually found in the cream. 1 Pasteurization 

 therefore limits the problem of preventing moldy butter very 

 largely to precautions against recontamination of cream and but- 

 ter after the cream leaves the pasteurizer and confines it to the 

 sanitary condition of the air, vats, pipes, pumps, churns, wash- 

 water and packing equipment and material. 



Moldy butter has in some instances also been traced to con- 

 taminated salt. 



The most probable cause of the salt as a source of moldy 

 butter lies in the contamination of the salt in the creamery after 

 the barrel is opened. In many creameries the salt is kept in a 

 room none too clean and in an atmosphere none too pure. If 

 the barrel is left open the surface of the salt is prone to become 

 contaminated with germ life of the air and may become the 

 carrier of mold. The salt barrels should be stored in a clean 

 place and a properly fitting cover should be provided for rem- 

 nant barrels. Such barrels should be covered immediately after 

 each removal of salt. 



Prevention of Mold in Butter. Moldiness in butter may 

 best be prevented by observing the following precautions : 



1. Pasteurize all cream, skimmilk and starter used. In 

 vat pasteurization heat to at least 145 F. and hold not less than 

 30 minutes. In flash pasteurization heat to 180 to 185 F. When 

 using the holding process draw a pailful of cream from the gate 

 of the vat as soon as the temperature of the cream reaches 145 

 F. and pour it back into the vat. This will insure proper heating 

 of the cream located in the gate and nipple. 



2. Use pure starter only. If the starter is contaminated 

 reject it. 



3. Thoroughly wash, flush and steam all vats, pipes, con- 

 duits and pumps daily. 



4. Rinse the churns daily with one batch of hot water 

 containing some good washing- powder and then with clean hot 

 water. The water must have a temperature of 180 F. or over. 

 Use thermometer to make sure. Lime the churns at regular 



1 Thorn and Ayres Effect of Pasteurization on Mold Spores. Jour. Agr. 

 Research, Vol. VI, No. 4, 1916. 



