CHEESE-MAKING 249 



ripening powers than the casein-digesting organisms, but it must not 

 be forgotten that these two great families of bacteria are still more 

 or less on trial, and it is not yet possible finally to decide on either 

 of them. Lloyd holds that though " the greater the number of lactic 

 acid bacilli in the milk the greater the chance of a good curd," still 

 " this organism alone will not produce that nutty flavour which is so 

 much sought after as being the essential characteristic of an excellent 

 Cheddar cheese." 



There are three difficulties to be encountered by dairymen 

 "starting" a ripening by the addition of a pure culture. First, 

 there is the initial difficulty of not being able to use pasteurised 

 milk for cheese, as such milk is uncoagulable by rennet (Lloyd). 

 Hence it is impossible to avoid some contamination of the milk 

 previous to the addition of the culture. Secondly, the continual 

 uncontaminated supply of pure culture is by no means an easy 

 matter. Thirdly, the maintenance of a low-temperature cellar to 

 prevent the rapid multiplication of extraneous bacteria will, in 

 some localities, be a serious difficulty. These difficulties have, 

 however, not proved insurmountable, and by various workers in 

 various localities and countries culture-ripening of cheese is being 

 carried on.* 



* As regards the Cheddar cheese industry in this country, Lloyd arrives at the 

 following five conclusions as a result of investigation : — 



1. To make Cheddar cheese of excellent quality, the Bacillus acidi laetici alone 

 is necessary ; other germs will tend to make the work more rather than less 

 difficult. Hence scrupulous cleanliness should be a primary consideration of the 

 cheese-maker. 



2. No matter what system of manufacture be adopted, two things are necessary. 

 One is that the whey be separated from the curd, so that when the curd is ground 

 it shall contain not less than 40 per cent, of water, and not more than 43 per cent. ; 

 the other point is that the whey left in the curd shall contain developed in it before 

 the curd is put in the press at least 1 per cent, of lactic acid if the cheese is required 

 for sale within four months, and not less than "8 per cent, of lactic acid if the cheese 

 is to be kept ripening for a longer period. 



3. The quality of the cheeses will vary with the quality of the milk from which 

 they have been made, and proportionately to the amount of fat present in that 

 milk. 



4. " Spongy curd " is produced by at least five organisms, and one of these is 

 responsible for a disagreeable taint found in curd. They occur in water. Hence 

 the desirability of securing clean water for all manipulative purposes, and also for 

 the drinking purposes of the milch cow. 



5. The fact that certain bacteria are found in certain localities and dairies is due 

 more to local conditions than to climatic causes. 



It is needless to remark that these conclusions once more emphasise the fact 

 that strict and continual cleanliness is the one desideratum for bacteriologically 

 good dairying. That being secured in the cow at the milking, in the transit, and 

 at the dairy, it is a comparatively simple step, by means of pasteurisation and the 

 use of good pure cultures of flavouring bacteria, to the successful application of 

 bacteriology to dairy produce. 



