616 



MILK 



the moisture of the curd and gradually decompose it. After a 

 few days there is usually no milk-sugar left. 



The fat is also enclosed in the curd, while the whey rarely 

 contains more than 1 per cent, of fat, usually less. 



As to the number of bacteria in cheese, the following figures 

 are instructive: 



Cheddar cheese (Harding and Prucha). 



After 6 hours 10,000,000 



After 1 day 30,000,000 



After 10 days 40,700,000 



After 50 days 10,200,000 



After 150 days 500,000 



Emmenthaler cheese (Lohnis* Handbuch). 



Fresh 750,000 



After 8 days 1,500,000 



After 14 days 8,600,000 



After 27 days..., 40,600,000 



After 71 days 28,800,000 



After 91 days 19,100,000 



After 136 days 550,000 



The ripening temperature influences the number of bacteria, 

 as the following table illustrates (Harrison and Connel) : 



Days. 60-67F. 37-40.5 F. 64-67 F. 38-40.5 F. 



1 523,000,000 523,000,000 635,000,000 635,000,000 



8.. 263,000,000 273,000,000 520,000,000 



15 14'5,000,000 489,000,000 264,000,000 475,000,000 



29 97,000,000 475,000,000 175,000,000 494,000,000 



54 12,000,000 471,000,000 253,000,000 



71-72 4,100,000 473,000,000 32,000,000 255,000,000 



According to these figures, there is an initial period, during 

 which the number of bacteria increases materially. This period 

 is followed by a decline in bacterial population, so that in fully 

 ripened cheese the number of bacteria is relatively small. Re- 

 cent work on the bacteria in cheese seems to indicate that these 

 conditions do not always obtain. Eldredge and Rogers, for 

 example, give the following figures: 



BACTERIA IN CHEESE AT DIFFERENT AGES 



Cheese No. 



17. 



95. 



Age of cheese. 



Weeks. 



3 



5 



7 



9 



11 



20 



7 

 7 

 11 

 12 

 Days. 



5 

 14 

 19 

 26 

 33 

 41 

 54 

 75 



Total number of bacteria, 

 millions per gram. 

 44 

 36 

 68 

 48 

 47 

 7.6 



36 

 29 

 77 

 55 



147 



136 



216.5 

 91.5 

 90.5 



123 

 50 



1210 

 97 

 380 

 260 

 140 

 210 

 250 

 120 

 210 



