Commonly called “ Wisconsin curd test.” Samples of suspected milk from each patron are placed in small glass jars holding about half a pint. The milk is heated to 90° F. and retained at this temperature to make conditions favorable for the growth of any abnormal bacteria or ferments that may be present. Cheese-makers add a small amount of rennet to the samples of milk so that a curd is formed that may be studied for defects: The samples are examined frequently during the day, and tested for odors or other defects that may have developed.