Condensed Milk and Milk Powder 



157 



is exposed to dampness, and if flies, bees, ants or cockroaches have 

 access to it. 



Again, the sugar may reach the milk through a sugar chute. 

 The lower end of the chute is usually located directly over the 

 steaming milk in the hot well. The vapors arising from below may 

 be condensed in the chute, causing its inside walls to become damp, 

 and sugar will adhere to the damp surface, forming a crust. If the 

 crust is not removed daily, its contamination with yeast and other 

 dangerous micro-organisms is almost inevitable and whenever this 

 crust peels off and drops into the milk, the contamination may be 

 carried into the finished product, giving rise to gaseous fermentation. 



Fig. 51. Yeast cells causing 

 gaseous fermentation 



This species is capable of fer- 

 menting sugar solutions contain- 

 ing 85% sucrose 



Fig. 50. 



Gaseous fermentation in sweetened 

 condensed milk 



Contaminated Machinery and Milk Conveyors. — Remnants of 

 milk may lodge in the condenser, in the vacuum pan, in the pipes 

 conveying the milk and condensed milk, in the cooling cans or coils, 

 in the supply tank of the filling machine, or the filling machine itself. 

 These remnants are all subject to contamination and may become 

 the source of fermented condensed milk. The strictest attention to 

 scrupulous cleanliness and continuous inspection of all parts of con- 

 veyors and apparatus which come in contact with the milk are the 

 only consistent safeguards against trouble from this source. 



Contamination Through "Cut-opens". — It is customary to empty 

 the contents of sample cans which are cut open for any purpose, 



