MAINE STATE COLLEGE 



The Lactometer and Fat Test for Cheese and Condensed 

 Milk Factories. 



Within the Itvst few months some inquiries have been received 

 from parties interested in cheese and condensed milk factories in 



regard to a test to determine the quality of the milk received at 

 these iustitutions. 



The fat test which very accurately tells the butter value of milk 

 does not give its actual value for making cheese or condensed milk. 

 For instauce, a factory may require milk of a certain standard, for 

 instance 3 per cent. fat. Such milk should contain about 9 per cent, 

 solids not fat. A patron may have milk that contains 6 per cent, 

 fat and 10 per cent, other solids. If he should dilute this milk 50 

 per cent, with water it would then contain 3 per cent, fat and 

 appear by the fat test alone to be up to the standard, while it would 

 be worth but little more than lialf as much for cheese or condensed 

 milk because it would contain but 5 per cent, solids not fat. There- 

 fore it is necessary to have recourse to some method to detect adul- 

 terations besides the fat test, to protect the above institutions and 

 milk buyers in general against fraud. It seems the height of 

 folly for our cheese and condensed milk factoTies to go on paying 

 for milk by quantity without regard to quality. It is simply 

 puttiug a premium on dishonesty and poor milk. For who would 

 turn milk from a nice Jersey herd into a factory if he received only 

 the same price per pound as his neighbor who has a herd of 

 ordinary animals yielding milk of much less value. 



The most common adulterations are the removing of cream and 

 the addition of water. By determining the fat and the solids not 

 fat, either or both of these adulterations are easily detected. 



In many states legal standards for fat and solids not fat have 

 been established in order to protect the public against fraud. In 

 some states the required standard is 3 per cent, fat, others 3.5 per 

 cent, and solids not fat about 9 per cent. Milk from a good sized 

 herd varies but little from day to day. Milk from a single cow 

 may vary quite widely in fat, but from a herd will seldom vary 

 more than 0.2 or 0.3 per cent, and solids not fat even less. 



It is rather difficult to fix any standard, so great is the variation 

 in different animals, but it is very rare that the mixed milk from 

 a large herd at any season of the 3'ear will fall below 12 per cent, 

 total solids unless it has been diluted. Milk containing less 

 than 9 per cent, solids not fat is suspicious, and a sample containing 



