96 Condensed Milk and Milk Powder 



degrees F. and it is advisable to heat the milk to 234 to 236 degrees 

 F., provided that the milk is in condition to stand this heat without 

 the formation of too' firm a curd. Where the maximum tempera- 

 ture to which the milk is raised in the sterilizer is 230 degrees F. or 

 thereabout, the raise of the last ten degrees should occupy from thirty- 

 five to forty-five minutes, and this time should be about evenly dis- 

 tributed over the ten degrees. 



Qualifications of the Processer. — The operator, or the person 

 directing the sterilizing process, should thoroughly appreciate the 

 complexity of the product, understand the cause and effect of the 

 many influencing factors, study the ever-changing conditions and 

 modify the process in accordance with prevailing conditions. He 

 should know that during the exceedingly hot summer days, when 

 the cows suffer from heat and are pestered with flies, the milk will 

 not stand as much heat without badly curdling in the sterilizer as 

 under more favorable conditions. He should know that toward and 

 during the fall months the organisms normally present in milk are 

 more resistant and require higher heat to be destroyed, than earlier 

 in the season. 



Rapid and Uniform Cooling. — As soon as the required heat 

 has been given the milk in the sterilizer, the steam should be turned 

 off and the exhaust and drain should be opened. When the tempera- 

 ture has dropped to about 220 degrees F., cold water should be turned 

 into the sterilizer while the cans are constantly in motion, until the 

 cans are cool enough to handle. There should be enough cold water 

 available to reduce the temperature to 70 or 80 degrees F. in 

 twenty minutes for gallons and in ten to fifteen minutes for small 

 size cans. The water pipe should be so arranged as to distribute 

 the water uniformly over the entire length of the sterilizer. 



If the process is to be successful, the processor must have as 

 nearly perfect control of the heat as possible. This means espe- 

 cially, that there must be plenty of water available to insure rapid 

 cooling and the water must be distributed over the cans uniformly. 

 Insufficient water supply and uneven distribution, of the water in 

 the sterilizer, means that some of the cans are exposed to the steril- 

 izing heat longer than others, causing lack of uniformity in the 

 smoothness and color of the milk of different cans of the same 

 batch. Delayed cooling owing to insufficient water supply has the 



