THE CHEMICAL CONTROL OF THE DAIRY. 



It was concluded that the milk had been peptonised, and was 

 insufficiently alkaline. 



Example e. The milk was curdled and the whey analysed. 

 The following were the analytical figures : 



Acidity, 

 Total solids, 

 Fat, . 

 Milk-sugar, 

 Ash, . 

 Solids not fat, 



26-2 



942 per cent. 

 1-27 

 5-53 

 0-60 

 8-15 



The milk was not bitter, but gave the biuret reaction. 



It was concluded from the low acidity and the high milk- 

 sugar that lactic fermentation 'was not the cause of curdling ; 

 from the biuret reaction being obtained, it was concluded that 

 an enzyme was the cause. 



The allegation that milk is sour may be due to it having 

 turned blue litmus paper red. All milk does this as well as 

 turn red litmus paper blue, and the complainant should be 

 invited to test with red litmus paper ; sour milk does not turn 

 red litmus paper blue. 



Milk is often alleged to be sour because, when used for making 

 milk puddings and custards with eggs, a clear whey runs out. 

 The curdling of the milk is due to the coagulation of the large 

 amount of albumin of the egg on baking. The following is an 

 analysis of a whey from rice pudding : 



Total solids, 

 Fat, . 

 Ash, . 

 Solids not fat, 



. 17-67 per cent. 

 . 0-82 

 . 0-85 



. 16-85 



It was very sweet and contained much cane sugar. 



PROBLEM VII. To determine the reason for milk being thick. 



Example a. The analytical figures were : 



Specific gravity, 

 Total solids, 

 Fat, . 

 Ash, . 

 Solids not fat, 



1-0262 



17-92 per cent. 

 9-36 

 0-71 

 8-56 



This sample contained an excess of cream, which made it 

 appear thick. 



Example b. The sample gave a blue colour on adding iodine 

 solution. It was thickened with starch (or flour). 



Example c. The milk was thick and, on dipping a glass rod 

 into it and lifting it out, a stringy mass adhered to it. On 



