•MILK PRODUCTS 59 



and add the sour milk germs in the form of a " starter," thus getting 

 a butter made from ripened cream, but avoiding the stronger 

 flavor caused by the miscellaneous germs. The flavor and aroma of 

 butter, then, depend upon the varieties of germs in cream. Butter 

 is thought to possess the finest flavor in May and June because at 

 this season the greatest variety of germs flourish in the milk. 



The chief reason why butter is so much better from certain 

 dairies than others is because the better dairies are the homes of 

 special kinds of germs, which give butter a good flavor and aroma, 

 while in the others — owing to want of cleanliness of the cows, barns, 

 milk rooms, employees or utensils — special germs of filth which are 

 unfavorable to good dairy products come to occupy the premises. 



The action of the germs is, then, the essential factor in the 

 production of good butter, as in all other departments of dairying. 

 As we have pointed out, the lactic acid germs, while in the minority 

 in the milk just drawn from the cow, soon gain ascendancy by 

 multiplying in milk or cream, and it is to this type of germ that the 

 ripening of butter and of cheese is chiefly due. 



We have also shown that to the miscellaneous germs in milk 

 and cream butter owes some of its flavor. But as some of 

 these are deleterious to flavor and aroma, and are not to be de- 

 pended upon, the endeavor has been made to employ only the lactic 

 acid bacilli to ripen cream. These are present in pure culture; that 

 is, they form the only type of germ in the commercial starters, 

 which may be bought in market in various shapes, as bottles of milk, 

 pastes, powders and pellets, all merely vehicles for the growth and 

 preservation of lactic acid germs. This starter is added to fresh 

 cream to ripen it. If the cream is already sour it is useless to add 

 a starter. It is best to first heat cream to 155 F., to destroy the 

 miscellaneous germs, before adding the starter containing the lactic 

 acid germs, but in this country, where the added flavor caused by 

 the miscellaneous germs is desired, the starter is more commonly 

 added to fresh cream. The starters which were first used consisted 



