June 2, 1920.] Agricultural Gazette of N,S.W. 431 



Neutralisation of Cream. 



L. T. MacINNES, Dairy Expert. 



The t)epartment of Agriculture has, since 1914, devoted much attention to 

 the investigation of the neutralisation of acidity in cream and milk. The 

 general adoption of pasteurisation by New South Wales butter factories in 

 1916-17 made a knowledge of neutralisation compulsory for our factory 

 managers and butter makers, as the quantity of cream received of acidity 

 low enough to be pasteurised without this process was not sufficient. The 

 average acidity of the cream delivered during the colder half of the year 

 would be from -3 per cent, to "35 per cent., while during the warmer season 

 it "would range from •{ to 'd per cent., and at times higher. Taking -2 per 

 cent, as a mean average acidity at which to pasteurise with good results, it 

 will be seen that reduction in acidity — varying in degree — is required 

 throughout the year. In making this reduction the greatest care is required, 

 and everything connected with the taking of acidity tests should be done 

 with exactness. 



The alkali solution used should be of the required standard, and its 

 strength checked from time to time. Each vat of cream to be treated should 

 be first well blended and then sampled and tested to ascertain the amount of 

 acidity present. After thoroughly mixing with it the neutralising agent 

 used, a second sample should be tested (say fifteen minutes after the com- 

 mencement of the process of neutralisation) in order to check the work being 

 done. 



Want of Method in Factory Procedure. 



At each of the nine or ten dairy schools for butter factory employees 

 annually conducted by the Department (at which there is an average aggre- 

 gate attendance of 120), instructions are given as to the making of these 

 tests, and students are shown how to ascertain the strength of the alkali 

 solution used. Not only at these schools but at factories throughout the 

 year the staff of the Dairy Branch is continuously impressing on all con- 

 cerned the necessity of exercising the greatest care in determining the 

 amount of acidity present. In spite of this, however, there is still too much 

 guess-work and a lack of method in factory procedure. Often the acidity 

 of the cream is arrived at by basing it on that of yesterday, and even 

 where tests are made daily the operator is frequently content with testing 

 the first vat to be neutralised and usinsr that test to calculate the amount of 

 acid present in all succeeding vats treated on that day. The average em- 

 ployee in a dairy produce factory does not seem to be able to grasp that the 

 smallest variation — even one-hundreth of 1 per cent. — froui the correct 



r — — • 



• Science Bulletin, No. 17, Department of Agriculture, New South Wales. "Neutral- 

 isation of Cream : Rate and Amount of the Reaction in ' Flash ' and ' Batch ' (or ' Hold- 

 ing ') Pasteurisers." A. A. Ramsay, Principal Assistant Chemi3t, Department of 

 Agriculture. 



