Section III., 1903 [ 3 ] Teans. E. S. C. 



I. — On the Analysis of Cheese. 

 By Thomas Macfarlane. 



(Read May 19th, 1903.) 



It is admitted by most writers on the subject that the methods in 

 use for the examination of cheese are not at present all that could be 

 ■desired. To mention only a recent authority, the authors of " The 

 Book of the Dairy '' state that in the investigation of ripe cheese "there 

 is no method which can be regarded as suitable or trustworthy." It 

 would serve no good purpose to endeavour to give in detail the various 

 processes which have been suggested or practised. It will be sufficient 

 to say that, in the analyses recorded in Konig's "Nahrungs-und Gcnuss- 

 mittel," the processes employed are quite diverse in character so far 

 as regards the determination of the nitrogenous constituents, and in 

 the most of cases, the "SticJistoffsudsta?iz" is obtained from, the nitrogen 

 percentage by multiplying it with the factor 6.25. In this manner a 

 sufficient approximation may, perhaps, be obtained for ordinary pur- 

 poses to the amount of total proteids contained in a ripe cheese, or to 

 the percentage of casein contained in it originally. But the method 

 cannot be regarded as scientifically accurate, and even for the practical 

 purposes of the dairyman, it has little or no value. 



The adoption of such a method neglects the fact that the original 

 casein has undergone a complete change in the process of ripening, as 

 well as the consideration that it is of the greatest importance that the 

 practical cheese maker should be made aware of the nature of this altera- 

 tion and of the degree to which it has extended in any sample of cheese. 

 With the object chiefly of developing a method of cheese analysis which 

 would be satisfactory from a practical point of view, I have thought it 

 advisable as far as possible to follow the plan of Manette and Musso, who 

 suggested making the following examinations : — " Determination of the 

 ''' percentage of water and bodies volatile at 115° C; preparation of a 

 " carbon bisulphide extract ; preparation of an alcoholic extract ; pre- 

 " paration of a watery extract ; determination of the quantity of bodies 

 " insoluble in bisulphide of carbon, alcohol and water ; determination of 

 " the ash ; determination of ammonia ; determination of the sum of the 

 "acids present; determination of the nitrogen; and, finally, the deter- 

 " mination of the nitrogen and ash in the different extracts, as well as 

 " the determination of the nitrogen and ash in the residues of the dif- 

 "ferent extracts." (Book of the Dairy, p. 274). A similar process of 



