250 SWEETSNKD CONDENSED MILK DEFECTS 



enzymes. It is, therefore, quite possible that some of these spe- 

 cies, or similar groups of species, may be instrumental in develop- 

 ing rancidity in sweetened condensed milk. It has been further 

 found that the milk products from certain individual cows, or 

 cows under certain physiological conditions are more prone to 

 develop a rancid flavor, than milk products from other cows or 

 cows under other conditions. 



Relation of Polluted Water to Rancidity. Polluted and 

 filthy water is usually contaminated with fungi and bacteria 

 belonging to the species enumerated above and which have been 

 found to be able to produce rancidity. It is, therefore, not im- 

 probable, where such water is used in the factory in the washing 

 of cans, conveyors, kettles, pipes, etc., in the condenser of the 

 vacuum pan and in the cooling tanks, as is frequently the case, 

 that the contamination of milk with it may result in the develop- 

 ment of rancidity. 



Relation of Climate to Rancidity. It is frequently claimed 

 that condensed whole milk shipped to the tropics turns rancid, 

 owing to exposure of this milk, rich in fat to a warm climate. 

 Advantage is sometimes taken of this argument, to justify viola- 

 tions of the laAv by skimming all, or a part of the milk before 

 condensing. This matter has been thoroughly investigated. All 

 experimental results show that sweetened condensed milk, made 

 properly and in conformance with the law, and containing all 

 the butter fat of the original whole milk, does not turn rancid 

 at any temperature. 



Putrid Sweetened Condensed Milk. 



General Description. Sweetened condensed milk is best 

 when fresh. With age it gradually develops a stale flavor which 

 frequently develops into a putrid odor and flavor. 



Causes and Prevention. The .purer the fresh milk and the 

 cane sugar, and the more careful the processor, the longer will 

 the condensed milk retain its pleasant flavor, provided that it is 

 stored at a reasonably low temperature. Age, however, will 

 cause the best sweetened condensed milk to become stale. The 

 appearance of the stale flavor is usually hastened when heating 

 the fresh milk with direct steam; also, where the fresh milk is 

 not heated to a sufficiently high temperature (below 176 cle- 



