242 SCIENCE AND PRACTICE OF DAIRYING. 



(6) In hard cheeses, the formation on the surface of the cheese of red 

 patches, or the coloration of cheese in blue or yellow patches, or the 

 discoloration of the entire mass of the cheese, so that it presents a bluish- 

 gray or black appearance. This happens very rarely. 



(7) In soft cheeses and sour-milk cheeses, the development of poisonous 

 properties in the cheese. In cheeses which have ripened too quickly, or 

 which have become overripe, certain kinds of bacteria develop, which give 

 rise to the formation of toxines. The cheese exercises poisonous effects, 

 and when eaten causes the development of symptoms, such as are seen in 

 gastro enteritis toxica or in cholera nostras. Poisoning with old cheese is 

 very rarely accompanied with fatal results. 



Again, almost every kind of cheese has its special disease. To go into 

 these even shortly would lead us far afield. 



The chief expense in cheese-making is due to the ripening. 

 Apart from the loss in weight which the ripening cheese suffers, and 

 the waste which this causes, the treatment and supervision of ripening 

 cheese demand the expenditure of much time and labour, and the 

 capital which is invested in the manufacture of cheese is locked up 

 through the long period during which ripening lasts. By making 

 the curd less dry, and by raising the temperature of the air in the 

 store-room, the ripening period may be considerably shortened, but 

 this can only be effected at the expense of the average good quality 

 of the cheese. This practice would prove practically advantageous 

 only under exceptional circumstances, as in the case of a very exten- 

 sive trade, and even then it would have to be carried out with very 

 great care. As a rule, the loss incurred from the production of a 

 number of spoiled cheeses would be greater than the saving effected 

 on the cost of manufacture. As a rule, the best course, from an 

 economical point of view, is to take precautions to secure a slow and 

 equable progress of the ripening, and not to depart from the average 

 period, which must be regulated as experience has shown to be best, 

 if the cheese is to acquire the best possible condition. In all fermen- 

 tation processes the best and finest results are obtained from the 

 processes that require comparatively the longest periods of fermen- 

 tation. 



In order to prepare cheeses of different kinds for the market, they 

 are subjected to special treatment, partly during the ripening process and 

 partly later. They are scraped and brushed, their surface is polished, 

 and is coloured with annatto, turnesol (Crozophora tinctoria), and other 

 colours, rubbed over with oil, wine, beer, extracts of leaves, &c., are ironed, 



