The PRODrcTiON of Clean Milk 



1931 



utensil. This contamination may be so great as to very seriously affect 

 the keeping quality of the milk. 



The proper procedure in cleaning any dairy utensil is as follows: First, 

 rinse the utensil in lukewarm water; second, wash it thoroughly with a 

 brush in a strong solution of hot water and washing powder, about a hand- 

 ful to a 12- or 14-quart pail of water; third, scald it with boiling water 

 or place it in a steam sterilizer. The reason for each step in the pro- 

 cedure is as follows: Lukewarm water is used for rinsing the utensil 

 because milk contains about .7 of i per cent of albumen, which is 

 coagulated and precipitated on the utensil so that it is very hard to remove 

 if water of a temperature of 160° F. or above is used. The utensil should 

 be washed in a strong solution of alkali powder and hot water because 

 normal milk contains about 4 per cent of milk-fat, and this solution will 

 dissolve any fat that is on the utensil. A brush is best to use for this 

 work because it enters the seams and crevices better and can be kept 

 clean much more easily than a cloth, which may be a breeding place 

 for bacteria unless great care is given to cleaning it each time after using. 

 The utensil must be sterilized in order to be perfectly clean. If water 

 is used for this purpose, it must have a temperature of 180° F. or higher 

 in order to kill all bacteria that may be present. The utensil should be 

 left in this water for at least several minutes in order to become sterile. 



The value of thorough sterilizing of utensils is shown by the following 

 results of bacteriological tests of milk samples taken from dairies where 

 the utensils were properly scalded and where they were not scalded. 

 All these samples were taken on the same days, as the producers delivered 

 the milk to the dealer. A's utensils were properly washed and scalded 

 twice a day, but B's were not scalded. 



Date, of taking sample 



1913 

 November i . . ■. 



1914 



January 20 



January 30 



March 14 



March 28 



April II 



April 20 



May 18 



May 25 



June I 



June 9 



June 18 



June 26 



Average 



