50 FOOD ADULTERATION" AND METHODS FOB DETECTION. 



seen slowly sinking to the bottom, leaving a train of a dark-brown col- 

 ored liquid behind them. This test appears to lead to more errors in 

 the hands of inexperienced operators than an} r other test here given. 

 Wrong conclusions may be avoided by working first with known 

 samples of coffee and chicory as suggested above. 



Many coffee substitutes are now sold as such and are advertised as 

 more wholesome than coffee. Notwithstanding the claims that are made 

 for them, a few of them contain a considerable percentage of coffee. 

 This may be determined by shaking a teaspoon ful in a bottle half full 

 of water, as described above. The bottle must be thoroughly shaken 

 so as to wet every particle of the sample. Very few particles of coffee 

 substitutes will float. 



CHEMICAL TESTS. 



Coffee contains no starch, while all of the substances, except chic- 

 ory, used for its adulteration and in the preparation of coffee substi- 

 tutes contain a considerable amount of starch. The presence of such 

 substitutes may, therefore, be detected by applying the test for starch 

 as given on page 58. In making this test less than a quarter of a tea- 

 spoonful of ground coffee should be used, or a portion of the ordinary 

 infusion prepared for the table may be employed after dilution. The 

 amount of water that should be added can only be determined by 

 experience. 



CONDIMENTAL SAUCES. 



Tomato catsup and other condimental sauces are frequently pre- 

 served and colored artificially. The preservatives employed are usually 

 salicylic acid and benzoic acid or their sodium salts. These products 

 may be detected by the methods given on pages 43 and 44. 



Coal-tar colors are frequently employed with this class of goods, 

 especially with those of a reddish tint, like tomato catsup. They may 

 be detected by the methods given on page 45. 



DAIRY PRODUCTS. 

 BUTTER. 



Methods are available which, with a little practice, may be employed 

 to distinguish between fresh butter, renovated or process butter, and 

 oleomargarin. 



These methods are commonly used in food and dairy laboratories, 

 and were originally suggested as household tests." They give reliable 

 results. At the same time considerable practice is necessary before we 

 can interpret correctly the results obtained. Some process butters are 

 on the market which can be distinguished from fresh butter only with 



"Patrick, Household tests for the detection of olcomargarin and renovated butter, 

 Farmers' Bulletin No. 131. 



