The Home Medical Library Volume V Part 7

=Cabbage=, crisp and firm, with a well-rounded and compact head.

=Carrots=, light red or yellow, with a regular, conical shape, sweet and crisp.

=Cauliflower=, white, compact head; any tinge of yellow or green generally indicates an inferior quality.

=Celery=, nearly white in color; large, crisp, and solid stalks, nutty in flavor.

=Cuc.u.mbers=, firm, crisp, with a smooth skin and white flesh.

=Lettuce=, the head close and compact; the leaves clean, crisp, and sweet. When it is too young or running to seed the taste is bitter.

Pale patches on the leaves are caused by mildew and are a sign of decay.

=Parsnips=, buff in color, with unforked roots, sweet and crisp.

=Potatoes=, underripe, green potatoes are unfit for food; they contain a poisonous substance which renders them actually harmful. Good potatoes should have a smooth skin and few eyes; the flesh pale and of a uniform color and of a firm consistency. A rough skin, with little depressions, indicates a disease called "scab"; dark-brown patches on the skin are due to a disease called "s.m.u.t." Potatoes with such diseases are of inferior quality. If green on one side, due to exposure to the sun when growing, the potatoes are unwholesome.

=Fruits.=--Underripe or green fruit should never be eaten. This condition may be easily detected by the color and consistency of the fruit. Diseased or decayed fruit is known by its change of color, softening, and external mold. Spots on fruit are often caused by a fungus which lowers its quality and renders it less wholesome.

=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 gla.s.sful 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 ma.s.s 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 ma.s.s 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 cla.s.ses, 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 cla.s.s 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 quant.i.ty, 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.

Milk should always be kept at a temperature below 50 F.; above that temperature the bacteria in it multiply with great rapidity and render it unfit for use.

Milk may be preserved for several days if "pasteurized" or "sterilized." Pasteurization consists of heating milk to a temperature of about 167 F., and maintaining it at that degree for twenty minutes. Sterilization means keeping the milk at a temperature of 212 F. for two hours and a half. Immediately after either process the milk should be cooled, then placed in absolutely clean, covered bottles and kept on ice. These methods are not only harmless but actually beneficial in that they destroy any disease germs that might be present.

Chemical preservatives are occasionally found in milk. They may be suspected if the milk is alkaline in reaction and has a disguised taste. The ones most commonly used are boric and salicylic acids and formaldehyde; the two former can only be detected by chemical tests too delicate and intricate to be used by the housewife. Formaldehyde may be tested for by using a solution of one drop of a ten per cent solution of ferric chloride to one ounce of hydrochloric acid.[6] Fill a small porcelain dish one-third full of this solution; add an equal volume of milk and heat slowly over a flame nearly to the boiling point, giving the dish a rotary motion to break up the curd. If formaldehyde is present, the ma.s.s will show a violet color, varying in depth with the amount present; if it is absent, the ma.s.s turns brown.

=b.u.t.ter.=--Good b.u.t.ter has a fresh, sweet odor and an agreeable taste.

It should be of the same color and consistency throughout, easily cut and adherent and not crumbly when molded into shapes. Pure b.u.t.ter is very light in color; nearly all that is sold is colored, in order to meet the popular demand for "yellow" b.u.t.ter; annatto and other vegetable and mineral substances are sometimes employed for this purpose. These coloring matters are generally harmless but may be detected by dissolving a portion of the b.u.t.ter in alcohol; the natural color will dissolve, while foreign coloring will not. b.u.t.ter should consist of eighty-five per cent fat, with the remainder water, casein, and salt. The most common methods of adulteration consist in an excess of water and the addition of oleomargarine. If an excess of water has been added it may be shown by melting the b.u.t.ter; the water and fat will separate in two distinct layers. Oleomargarine has a distinctive meaty smell, like that of cooked meat, and lacks the characteristic odor of pure b.u.t.ter. If pure b.u.t.ter is melted in a spoon, it will not sputter; if oleomargarine is present, it will.

The preservatives sometimes used, namely, boric and salicylic acids and formaldehyde, can only be detected by chemical tests.

=Eggs.=--Two methods may be used to detect stale eggs. First: make a solution of one part of table salt to ten parts of water and immerse the suspected egg; if it sinks, it is perfectly fresh; if it remains in the water below the surface, it is at least three days old, and if it floats, it is five or more days old.

Second: hold the egg between a bright light and the eye. If it is fresh, it will show a rosy tint throughout, without dark spots, as the air chamber is small; if not fresh, it will look cloudy, with many dark spots present.

=TEA AND COFFEE.=--These substances are extensively adulterated, but the adulterants are almost without exception harmless.

=Tea.=--The commonest forms of adulteration of tea are as follows: (_a_) Exhausted tea leaves which have already been used are dried and added. Their presence may be detected by the weakness of the infusion, made from a given quant.i.ty of the suspected tea, compared with a similar infusion made from tea known to be pure. (_b_) Leaves from other plants are sometimes dried and added; these are easily shown if an infusion is made and when the leaves are thoroughly wet unrolling and comparing them. (_c_) Green teas may be "faced" or colored with Prussian blue, indigo, French chalk, or sulphate of lime; black teas may be similarly treated with plumbago or "Dutch pink." If teas so treated are shaken up in cold water the coloring matter will wash off.

(_d_) Sand and iron filings are occasionally added for weight; observation, and the fact that they sink when tea is thrown in water, will show their presence. Iron filings may be readily found by using a magnet. (_e_) The presence of starch may be shown by was.h.i.+ng the tea in cold water, straining it, and testing the solution in the following manner: dissolve one-half teaspoonful of pota.s.sium iodide in three ounces of water and add as much iodine as the solution will dissolve; a few drops of this solution added to the suspected sample will give a blue color if starch is present.

=Coffee.=--Coffee should always be purchased in the bean, as ground coffee is much more frequently adulterated and the foreign substances are more difficult to detect.

The adulterants commonly used are: chicory, peas, beans, peanuts, and pellets of roasted wheat flour, rye, corn, or barley.

Fat globules are always present in pure coffee; their presence may be shown by the fact that imitation coffee sinks in water, while pure coffee floats.

Chicory is the most frequently used adulterant; it is added for flavor and to produce a darker infusion, thus giving the impression of greater strength. It is perfectly harmless and as a drink is actually preferred by some people. Its detection is comparatively easy. Chicory grains are dark, gummy, soft, and bitter; coffee grains are hard and brittle; a small amount put in the mouth will demonstrate the difference. Chicory will often adhere to the wheels of a coffee grinder, clogging them on account of its gummy consistency.

When a sample of adulterated coffee is thrown in water the pure coffee floats and leaves the water unstained; chicory sinks almost instantly, coloring the water, while peas and beans sink more slowly but also color the water.

Peas and beans are also detected by the polished appearance of the broken or crushed grains in marked contrast to the dull surface of crushed coffee.

The presence of peas, beans, rye, wheat, bread crumbs, and allied substances may be shown by the fact that they all contain starch.

Make a ten per cent infusion of the suspected coffee; filter it, and decolorize the solution by boiling it with a piece of animal charcoal.

Test the decolorized solution by slowly adding a few drops of the "pota.s.sium-iodide-iodine solution," directions for preparing which were given under heading of "Tea." A resulting blue color will indicate the presence of starch.

=COCOA AND CHOCOLATE.=--The adulterants of these substances are generally harmless, as they usually consist of flavoring extracts, sugar, starch, flour, and animal fats. No tests other than flavor, consistency, and smoothness need be considered. Good cocoa and chocolate should be slightly bitter, with a pleasant characteristic odor and taste; they should have a smooth, even consistency and be free from grit or harsh particles.

=CANNED AND BOTTLED VEGETABLES AND FRUITS.=--In general, acid substances, such as tomatoes and fruits, should not be canned in tin, as the action of the acid tends to dissolve the tin. It is better, therefore, to purchase these articles in gla.s.s.

After opening the can the odor and appearance of the contents should be noted. The odor should be clean and fresh, and the slightest trace of any sour, musty, or disagreeable smell should cause the rejection of the food. The appearance should be clean, with no mold; the consistency and color of the fruit or vegetables should be uniform throughout. If the color is brighter than that of a similar article when canned at home, the presence of artificial coloring matter must be suspected. The brilliant green of some brands of peas, beans, or Brussels sprouts is produced by the addition of the salts of copper.

This may be proved by leaving the blade of a penknife in the contents of the can for a short time; if copper is present it will be deposited on, and discolor, the blade.

Brightly colored fruits should excite suspicion; this same dictum applies to all brightly colored jams and jellies, as the colors are usually produced by the addition of carmine or aniline red.

The presence of preservatives, salicylic and boric acids, the benzoates, etc., can only be proved by delicate chemical tests.

=SUGAR.=--Pure granulated or powdered sugar is white and clean. The presence of glucose should be suspected in sugar sold below the market price; it is perfectly harmless, but has a sweetening power of only about two-thirds that of sugar and is added on account of its cheapness and to increase the bulk.

If sand, dirt, or flour are present they may be detected by observation, or by was.h.i.+ng the suspected sample in water; flour will not dissolve, sand will sink, and dirt will discolor the water.