DETECTION OP TAINTS 201 



WISCONSIN CURD TEST. 



This test originated at the Wisconsin Dairy School. 

 The name of the test implies that the samples of milk 

 to be tested are curded, which is accomplished in a man- 

 ner similar to that in which milk is curded for cheese 

 making. 



The Wisconsin Curd Test is frequently spOKen 01 as 

 "fermentation test," since the process involved consists in 

 fermenting the milk by holding it at a temperature at 

 which the bacterial fermentations go on most rapidly. 



Apparatus. This consists of one pint cylindrical tin 

 cans placed in a tin frame, and of a well insulated box 

 made so that the tin frame will nicely slide into it. Added 

 to this is a case knife, and a small pipette used to measure 

 rennet extract. 



The construction of the box and the position of the cans 

 inside is illustrated in Fig. 51. This box consists of 

 three-eighths inch lumber, the inside of which is lined with 

 a quarter inch thickness of felt. Narrow strips are tacked 

 on the felt and tin upon these, the object of the strips 

 being to prevent conduction of heat by contact of the tin 

 with the felt. The cover of the box is constructed in the 

 same way and made to fit tight. This construction makes 

 it possible to maintain a nearly constant temperature of 

 the samples which are surrounded by water as shown in 

 the illustration. 



Making the Test. A curd or fermentation test is made 

 at the creamery by selecting from each patron about two- 

 thirds of a pint of milk and placing this in the tin pint 

 cans after they have been thoroughly sterilized. Each 

 pint can should be provided with a sterilized cover which 

 is placed upon it as soon as the sample has been taken. 



