176 MILK AND DAIRY PRODUCTS PART 



form of adulteration. The maximum quantity of water which 

 is allowed to be present in butter offered for sale is fixed by 

 law in many countries. Fortunately this form of falsification 

 is easily detected by simply determining the percentage of 

 water in the butter (p. 135). 



III. ADDITION OF PRESERVATIVES. 



In many countries the addition of preservatives to butter is 

 legally forbidden, the only exception being made in the case of 

 common salt, which is everywhere allowed. Boracic acid and 

 its salts are the most usual preservatives, but occasionally some 

 of those mentioned as preservative materials for milk (p. 119) 

 are met with. As regards analytical methods for the detection 

 of preservatives in butter those described for milk are generally 

 applicable. The fat must first be got rid of as completely as 

 possible by melting the butter and carefully separating the 

 water from it in a separating funnel. The water can then be 

 tested in the usual way. Relatively smaller quantities are to be 

 taken than is the case in the analysis of milk. 



D. DETECTION OF COLOURING MATTER IN BUTTER. 



The colouring of butter by the addition of some colouring 

 matter is now so general and so largely practised that hardly 

 anybody stays to consider whether or not such a course is 

 morally right or not. Artificial colouring of butter has as its 

 object the attainment of the bright yellow colour which is 

 naturally present during the summer months. Only very small 

 quantities of harmless colouring matters are used as a rule, so 

 that there has not been any necessity for steps to be taken 

 against the practice. The public has become accustomed to 

 buying butter of the same colour all the year round, so that it 

 is difficult to abolish the practice. 



It therefore only becomes necessary to see that the colouring 

 of the butter is not done with any poisonous or injurious 

 substances. 



Until the last few years butter was always coloured with 

 vegetables dyes, and the best of that class is annatto, which is 

 got from a South American tree, Bixa orellana. The dye is 

 got by vigorously stirring up the ripe and open fruit capsules 



