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DAIRY LABORATORY GUIDE 



EXERCISE 7 



INFLUENCE OF BARN VENTILATION ON DAIRY PRODUCTS 



Object: To determine the influence of barn ventilation 

 upon the purity and keeping quality of market milk. 



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

 mometer, and acid testing outfit. 



Steps : 1 . Secure samples of milk from a stable equipped 

 with a good ventilating system, and from another stable with 

 no provision for ventilation. 



2. Test the samples in each set for acidity; then strain 

 the milk through sterile cheesecloth. 



3. Sterilize a number of glass jars and then transfer the 

 milk to the jars and cover tightly. 



4. Set the samples in a place that can be kept at a con- 

 stant temperature of about 70 F. 



5. Examine one jar in each set at intervals and test for 

 odor, flavor, and acidity. 



6. Keep one jar in each set unopened and note the 

 appearance of curd. Always use a sterilized pipette in exam- 

 ining the samples. 



Data: 



