40 Condensed Milk and Milk Powder 



daily true where the boilers are located at some distance from the 

 hot wells and the steam pipes are not well insulated, causing the 

 steam to be "wet."' It is estimated that the amount of extraneous 

 water thus added to the milk, increases the bulk of the milk by one- 

 sixth of its original volume. The steam is often associated with 

 impurities, such as cylinder oil from the engine, boiler compounds 

 used in the boilers, scales from the inside of the pipes, etc. These 

 various impurities cannot possibly improve, but may seriously injure 

 the quality of the milk. It is quite probable, also, that the direct 

 contact of live steam with milk, has no beneficial effect on its ingred- 

 ients. It is generally conceded by those who have given this matter 

 careful thought, that the turning of steam direct into the milk 

 shortens the life of the product and causes it to develop a stale 

 flavor, which may degenerate into an oily flavor. The same defect is 

 noted also when cream is heated by turning steam into it. The pro- 

 longed exposure of the milk to the condensing process, as the result 

 of the addition to the milk of considerable quantities of condensed 

 steam, further may be injurious to the milk. 



Any method of heating that does not require direct contact of 

 the steam with the milk is preferable, provided that it makes possible 

 thorough heating to the required temperature without burning the 

 milk. Practically all of the other methods above referred to accom- 

 plish this. 



ADDITION OF SUGAR 



Considerable quantities of sucrose are added to the condensed 

 milk for the purpose of preserving it. 



Kinds of Sugar. — In order to convey to the milk preservative 

 properties, that kind of sugar must be used, which does not readily 

 undergo fermentation and which has the power of inhibiting bac- 

 terial activity when dissolved in a concentrated solution. Glucose 

 could be purchased at a very low cost, but it is not suitable for this 

 purpose, since it is, in itself, very unstable and fermentable. It has 

 no preservative qualities, even in concentrated solutions. Sucrose, 

 saccharose, or cane sugar, C 12 H 22 O n , properly refined, ferments 

 with difficulty in concentrated solutions, and has the power of re- 

 tarding the growth of bacteria and other ferments ordinarily present 

 in sweetened condensed milk. It is, therefore, very satisfactory and 

 useful in this connection. 



