MILK PRODUCTS 327 



South America and the West Indies. Annatto is generally 

 supplied for use in the form of a faintly alkaline solution, and 

 this is added to the milk or cream. It is considered to be 

 harmless, and its presence is not regarded as adulteration. 



Preservatives. Borax and boracic acid are sometimes 

 added to butter as preservatives. Other substances have been 

 recommended, but they do not appear to have been extensively 

 used. When butter is properly made, most of the bacteria are 

 removed in the butter milk and in the subsequent process of 

 washing. It does not, therefore, readily undergo fermentation, 

 and there is no great need of preservatives beyond the small 

 quantity of salt that is commonly used. 



Margarine. Margarine is intended to be used as a sub- 

 stitute for butter, and is made to resemble it as nearly as 

 possible. The melting-point is adjusted by mixing the harder 

 tallows with vegetable oils in due proportion. Various nut 

 oils are used to improve the flavour and odour, and a certain 

 amount of water, salt, and colouring matter are incorporated 

 with the fat. When free from objectionable impurities mar- 

 garine is a wholesome food, and many people prefer it to bad 

 butter. It can be sold at a lower price, and to represent it as 

 butter is a fraud. 



Cheese. The term cheese is applied to a variety of pro- 

 ducts prepared from substances of different composition, by 

 processes which, though similar in general principle, yet differ 

 in many important details. These products are in most cases 

 subsequently exposed to progressive fermentative changes for 

 longer or shorter periods, and, in the end, they differ widely 

 both in composition and properties. 



The substances from which cheese is prepared are : 

 (i) cream, (2) whole milk, (3) whole milk with added cream, 

 (4) milk from which a larger or smaller proportion of the 

 cream has been abstracted. In a purely qualitative sense, 

 these substances are all much alike ; but they differ widely in 

 regard to the percentages of water and of fat which they 

 contain. The percentage of water is in some respects a matter 

 of secondary importance, but the percentage of fat or rather 

 the ratio of fat to casein is all important. 



