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DAIRY LABORATORY GUIDE 



EXERCISE 8 



CLEANLINESS AND THE KEEPING QUALITY OF MILK 



Object: To determine the effects of cleanliness upon 

 the keeping quality of milk. 



Apparatus : Samples of milk, covered pint jars, thermom- 

 eter, acid testing outfit, and sediment tester. 



Steps: 1. Secure the following samples of milk: from 

 clean stables, from dirty stables, strained, unstrained, from 

 wagon, and pasteurized milk. 



2. Test each sample for acidity and sediment. 



3. Sterilize six glass jars and number them from 1 to 6. 



4. Pasteurize a sample of milk at 140 F. for 15 minutes. 

 Have cap jars. 



5. Fill a jar with each of the samples; then cover 

 tightly and set at 60 F. 



6. Examine each jar at intervals of 24 hours and test 

 for acidity, odor, and flavor. 



7. Note the length of the time required to curdle and the 

 appearance of curd from each sample. 



Data: 



