52 



FACTORY SANITATION 



present in milk are capable of doubling in number once every twenty 

 minutes, it is essential that the milk either be heated to high enough 

 temperatures to destroy germ life, or be cooled to a temperature low 

 enough to stop growth and multiplication, as soon as possible. 



Both practices are feasible, but to heat the large volumes of 

 milk that arrive at the factory, all within a few hours, would tax 

 the equipment of the factory under average conditions very heavily. 

 And unless the condensery were equipped with very large vacuum 

 pan capacity, much of this heated milk would have to lie idle in the 



Fig. 10. Glass-lined tank for cooling and holding milk before manufacture 

 Courtesy of The Pfaudler Company 



forewarmers for hours, awaiting its turn for condensation. This 

 would be undesirable and might prove harmful to the quality of the 

 finished product. 



Efforts have, therefore, been made, especially within recent, 

 years, to provide a practical and economical method of cooling the 

 milk as soon as it arrives and of holding it at a low temperature 

 until ready for heating and condensing. This has led to diverse 

 practices, such as running the milk over a surface coil cooler into 



