CEREALS AND THEIR PRODUCTS—Cereals.—Particularly when bought in original packages cereals are generally pure and unadulterated. When bought in bulk there may be found dust, dirt, worms, insects, and excessive moisture. These may all be determined by careful inspection. The presence of an undue amount of moisture adds greatly to the weight of cereals and is therefore a fraud. Cereals should be dry to the touch and the individual kernels or particles separate and distinct.
Flour.—By this general term is meant the ordinary wheat flour. It should not be too moist, should have a fine white appearance, remain lumpy, or hold its form, on pressure, not show any particles which cannot be crushed, and when a handful is thrown against the wall, part of it should adhere. The odor and taste should be fresh and clean and not musty or moldy.
The common adulterants are corn and rice meal. If a sample of the flour be thrown on the surface of a glassful of water, the corn and rice, being heavier, will sink; grit and sand may be detected in the same way. If the flour has been adulterated with mineral substances it may be shown by burning a portion down to an ash; the ash of pure flour should not exceed two per cent of the total amount; if mineral substances are present the amount of ash will be greatly increased.
Alum is sometimes added to flour in order to give it a whiter appearance and to produce whiter and lighter bread; it is most unwholesome. It can be detected by the so-called "logwood" test, which is prepared and used as follows:
Make two solutions. The first: a five per cent solution of logwood chips in alcohol. The second: a fifteen per cent solution of ammonium carbonate in water. Make a paste of one teaspoonful of the flour and an equal amount of water; mix with it one-quarter of a teaspoonful of the logwood solution; follow this immediately with one-quarter of a teaspoonful of the ammonium carbonate solution. If alum is present, the paste will show a lavender or blue color; if absent, the mass will become pink, fading to a dirty brown. If the result is doubtful, set the paste aside for several hours, when the colors will show more plainly.
Bread.—Bread should be well baked and not too light or too heavy; the crust should be light brown and adherent to the substance of the bread. The center should be of even consistency, spongy, and firm; it should not pit or be soggy or doughy. The pores or holes should be of practically the same size throughout.
Exceedingly white, light, or porous bread shows the presence of alum. It may be detected by means of the solutions already mentioned in the "logwood" test. Mix one teaspoonful of each solution and add three ounces (six tablespoonfuls) of water; pour this over a lump of bread, free from crust and about an inch square. After the bread has become thoroughly soaked, pour off the excess of liquid and dry the bread in the dish; if alum is present, the mass will show a violet or blue tint, more marked on drying; if absent, a brownish color will appear.
Baking Powders.—Baking powders are of three classes, all having sodium bicarbonate (baking soda) as their alkaline salt. The first style is the commonly used and wholesome mixture of cream of tartar and baking soda; the second has calcium phosphate for the acid salt, and the third contains alum. All have a certain proportion of starch to absorb moisture. Of these the alum powders are the most harmful and should be avoided. Practically all of the well-known brands of baking powder are of the first-mentioned class and wholesome, and are rarely adulterated.
DAIRY PRODUCTS—Milk.—Pure milk should have a specific gravity of from 1.027 to 1.033. Its normal reaction is neutral or slightly acid; it should never be strongly acid. If it is strongly alkaline, i. e., turning red litmus paper blue, it is pretty certain that something in the way of a preservative has been added to it. When left standing for a few hours the cream should show as a slightly yellowish top layer, one-tenth or more of the whole amount; the milk below the cream should be lighter in color and with the slightest bluish tinge. If the color is of a yellowish tinge throughout, the addition of coloring matter must be suspected. "Annatto," a vegetable pigment, is used to give a "rich" tint to milk. To detect it, add one teaspoonful of baking soda to one quart of milk and immerse in it a strip of unglazed paper; in a few hours examine the paper; if annatto is present, it will have become an orange color.[5]
If the whole milk has a blue and thin appearance, or if the cream is scant in quantity, it has probably been diluted with water. The popular idea that chalk is sometimes added to poor milk to make it appear of better quality is erroneous; chalk would always show as a precipitate, as it does not dissolve, and the presence of such a sediment would be a too obvious adulteration to be practiced.