352 Milk and Its Products 



To DETERMINE LACTIC ACID, USING 17.6 c. c. OF MILK OR CREAM 



Instead of determining lactic acid as described above, it is often 

 more convenient to make the tablet solution of such a strength that 

 1 c. c. of the solution will neutralize .01 per cent of lactic acid in the 

 amount of milk or cream taken. Since a 17.6 c. c. pipette is always 

 found where there is a Babcock testing .outfit, 17.6 c. c. is a very con- 

 venient assay, as it does not necessitate procuring an additional 

 pipette. If 5 Farrington tablets are dissolved in 97 c. c. of water the 

 solution will be of such a strength that each c. c. of solution 

 will neutralize .01 per- cent of lactic acid in 17.6 c. c. of milk, and the 

 total number of c. c. used will indicate the amount of lactic acid present 

 in hundredths of one per cent; e. g.: 



5 tablets are dissolved in 97 c. c. water, and 35 c. c. of the solu- 

 tion are required to neutralize the lactic acid in 17.6 c. c. of cream; 

 the percentage of lactic acid present is therefore .35 per cent. 



To SELECT MILK FOR PASTEURIZATION 



Dissolve any convenient number of Farrington alkaline tablets in 

 an equal number of ounces of water. Provide any convenient small 

 measure, and to one measure of milk add two measures of the pre- 

 pared tablet solution. If the milk remains uncolored, it contains 

 more than .2 of 1 per cent of acid, and is too sour to be safely 

 used. If it is colored pink, it contains less than .2 of 1 per cent of 

 acid, and may safely be used for pasteurizing or sterilizing. Or, the 

 tablet solution will be of very nearly the same strength, and may be 

 used in the same way, if 3 tablets are dissolved in 90 c. c. of water. 



To PREPARE VISCOGEN FOR RESTORING THE CONSISTENCY 

 OF PASTEURIZED CREAM 



Two and one-half parts by weight of a good quality of granulated 

 sugar are dissolved in five parts of water, and one part of quick lime 

 gradually slaked in three parts of water. The resulting milk of lime 

 is strained and added to the sugar solution. The mixture should be 

 agitated at frequent intervals, and after two or three hours allowed 

 to settle until the clear liquid can be decanted off. This clear liquid 

 (viscogen) is the part used and should be kept in well-stoppered bottles, 

 as it loses strength and becomes dark-colored when exposed to the air. 

 The darkening in color, however, does not impair its usefulness. 



