DAIRY LABORATORY GUIDE 



EXERCISE 9 



TEMPERATURE AND THE KEEPING QUALITY OF MILK 



Object : To determine the effect of temperature upon the 

 keeping quality of milk. 



Apparatus: Samples of freshly drawn milk, sample jars, 

 thermometers, and acid testing outfit. 



Steps: 1. Wash six sample jars thoroughly; then dry 

 and number them from 1 to 6. 



2. Test the milk for odor, flavor, and acidity. 



3. Fill the sample jars, cover each with a small piece of 

 cheesecloth, and set them at 90, 70, and 50 F., respectively. 

 Have arrangements to keep the temperature reasonably uni- 

 form. A fireless cooker well insulated will answer the pur- 

 pose well. Always have as nearly farm conditions as possible. 



4. Record the time of setting the samples; then examine 

 them regularly at intervals of 24 hours. 



Data: 



Application: 1. At which temperature does the acid 

 develop the most rapidly? 



2. What are the effects of temperature on the odor? On 

 the flavor? On the appearance of the curd? 



