27 



4. Opportunities for use in cheese making. — The Babcoek test finds 

 occasion for use in cheese making; as follows: (1) Testing milk of indi- 

 vidual i^atrons when the dividends are made on the basis of the milk 

 fat, (2) testin«: milk to ascertain if it has been seriously skimmed, (3) 

 testint; milk to use fat as a basis for estimatin": yield of cheese and 

 refjulatinj; amount of salt used, (4) testing; whey and press drippin{2;s 

 to ascertain if fat loss is excessive, and (5) testin<ij cheese for amount 

 of fat. 



5. Api^aratus and materials used in testing milk. — The following: list 

 includes the apparatus and materials used in testing; milk: (1) Test 

 bottles, graduated from to 10 per cent, so that each division repre- 

 sents two-tenths of 1 per cent when 17.5 cubic centimeters (18 grams) 

 of milk are used; (2) pipette for measuring milk, holding 17.6 cubic 

 centimeters to mark; (3) measure for acid, holding 17.5 cubic centi- 

 meters to mark; (4) centrifugal machine, having a wheel 12 to 20 

 inches in diameter, easily capable of being run at a speed of 700 to 

 1,200 revolutions a minute, and (5) commercial sulphuric acid having 

 a specific gravity above 1.82 and below 1.83, preferably just 1.825. 

 [The lecturer should have all the apparatus and materials at hand and 

 explain each in full detail.] (Reference No. 3, p. 101, or No. 12, 

 pp. 34-54.) 



6. Sampling milk for testing. — Milk that has soured and thickened or 

 on the surface of which cream has risen and dried somewhat, or milk 

 the fat of wliich has partially churned, is difficult to sample; but these 

 difficulties should not be common in cheese-factory work. The sam- 

 ])les to be tested must be thoroughly mixed (reference No. 3, p. 103, 

 or No. 12, p. 26). 



7. Composite samples. — In order to avoid testing milk daily, com- 

 posite samples may be prepared and tested for a week or ten days. 

 Much care should be used in preparing and keeping composite samples 

 (reference No. 3, p. 110, or No. 12, p^ 134). For use of milk thief in 

 taking composite samples, see reference No. 8, p. 29. 



8. Performing test. — Following are the steps to be followed in testing 

 milk: (1) Running sample of milk into test bottle (reference No. 3, 

 p. 104, or No. 12, p. 28). (2) Adding acid to milk in test bottle (refer- 

 ence No. 3, p. 104, or No. 12, p. 28). (3) Mixing milk and acid 

 (reference No. 3, p. 105, or No. 12, p. 30). (4) Whirling test bottles 

 and addmg water (reference No. 3, p. 105, or No. 12, p. 31). (5) 

 Measuring fat (reference No. 3, p. 106, or No. 12, p. 32). [The lecturer 

 should perform and explain every operation in detail, making clear 

 the reasons for each step. He should then require each student to go 

 through and explain each detail until an independent degree of skill 

 has been attained.] 



9. Testing whey hy Babcoek method. — The test is conducted in the 

 usual way, but special bottles having small necks should be used 

 (reference No. 3, p. 108, or No. 12, p. 74). 



