FATS AND OILS 60 =Lard=--Adulterations of--Cottonseed oil--Cottonseed stearin--Beef stearin. =Olive Oil=--Adulterations of--General test--Cottonseed oil--Peanut oil--Sesame oil--Rape oil. CHAPTER XII BEVERAGES 65 =Coffee=--Adulterations of--General test--Coloring matter-- Imitation coffee beans--Chicory. =Tea=--Adulterations of--Foreign leaves--Exhausted tea leaves--Lie tea--Facing--Catechu. PURE FOOD TESTS CHAPTER I DAIRY PRODUCTS MILK Milk is adulterated by watering, removing the cream or by adding some foreign substance. Formaldehyde, boric acid or salicylic acid may be added to preserve the milk. Annatto, caramel or some coal-tar dye is added, sometimes to improve the color of the milk, and at other times to cover up traces of watering. Gelatin and starch are added for the same purpose, though they are not frequently used. ARTIFICIAL COLORING MATTER ANNATTO Add acid sodium carbonate to a sample of the milk until it shows a slight alkaline reaction. Immerse a piece of filter-paper and leave it in for 12 or 15 hours. If annatto is present, there will be a reddish-yellow stain on the paper. CARAMEL _Leach’s Method._--Warm 150 cc. of the sample and add 5 cc. of acetic acid, then continue heating it nearly to the boiling point, stirring while it is being heated. Separate the curd by gathering it with the stirring rod or by pouring through a sieve. Press out all the whey from the curd and macerate the latter for several hours (10 to 12 hours) in 50 cc. of ether. It is best to do this in a tightly corked flask, shaking it frequently. If the milk was uncolored or colored with annatto the curd when thus treated will be white. If the curd is a dull brown color caramel was probably used to color the milk. Confirm its presence by shaking a portion of the curd with concentrated hydrochloric acid (sp. gr. 1.20) and gently heating. If the acid solution turns blue while the curd does not change its color, caramel was used to color the milk. (Remember that the ether-extracted curd must be brown.) COAL TAR COLORS _Lythgoe’s Method._--Mix in a porcelain vessel about 15 cc. each of the sample of milk and hydrochloric acid (sp. gr. 1.20) and break up the curd into coarse lumps by shaking gently. If an azo-color was used to color the milk this curd will be pink, but the curd of normal milk will be white or yellowish. STARCH The presence of starch in milk may be detected by heating a small quantity of the milk to boiling. When it has cooled add a drop of iodin in potassium iodid, and if starch is present there will be a blue coloration. GELATIN