BUTTERMILK. 361 



by any statute, and if buttermilk is to be sold there is no reason 

 why it should contain any added water. It is probable, how- 

 ever, that should a sample of buttermilk taken under the Sale 

 of Food and Drugs Acts be found to contain a small percentage 

 of added water, the Public Analyst would advise his authority 

 that it is a custom to add water during churning, and a prosecution 

 for the addition of small percentages is improbable. 



The Use of Starters in Butter- making. — The acidity of 

 the cream should be determined before churning, if ripened 

 cream is used. An acidity of about 60° will generally yield 

 good results. 



In order to ensure that a good flavoured butter is produced, 

 it is necessary that the proper organisms are present ; this is 

 best ensured by pasteurising the cream, and after cooling adding 

 a starter, which has been found to produce a good flavour. The 

 starter provides an enormous excess of lactic acid bacteria, which 

 at the ripening temperature develop rapidly and overgrow any 

 other organisms that may have found entrance. 



A starter is prepared by sterilising 1 to 2 litres of milk, adding 

 a tube of one of the preparations on the market, which are pure 

 cultures of lactic acid bacteria, and keeping the milk at about 

 70° F. till thick. 



A rough, but usually very successful, method is to allow a 

 specimen of milk, which develops a clean acid ta§te on keeping 

 to stand at about 70° F. till sour. The lactic acid organisms 

 arc very active at this temperature, and, as they tend to over.grow 

 any others that may be present, a fairly pure culture is the 

 result. 



Starters may be kept going by adding to 1 to 2 litres of nulk 

 that has been sterilised a little of a previous starter, and keeping 

 at 70° F. 



