The adulteration of food of almost every kind is unfortunately so common a custom, that our limited space will merely allow of our noticing a few of the leading points in regard to it.
Wheal-flour is not unfrequently adulterated with one or more of the following sub stances: flour of beans, Indian corn, rye, or rice, potato-starch, alum, chalk, carbonate of magnesia, bone-dust, plaster of Paris, sand, clay, etc. The organic matters—the infe rior flours and starch—do little or no serious harm; most of the inorganic matters are positively injurious, and of these, alum (one of the commonest adulterations) is the worst. The beneficial action of wheat-flour on the system is in part due to the large quantity of soluble phosphates which it contains. When alum is added, these phos phates are decomposed in the process of making bread, the phosphoric acid of the phos phates uniting with the alumina of the alum, and forming an insoluble compound; the beneficial effect of the soluble phosphates is thus lost.
Arrow-root is adulterated with potato-flour, 'sago, starch, etc. Out of 50 samples examined by Dr. Hassall, 22 were adulterated, and in 10 of the samples there was scarcely a particle of the genuine article.
Sugar of the inferior kinds is occasionally adulterated with flour, gum, starch-sugar, etc. It is oftener, however, impure than intentionally adulterated.
Pepper is adulterated with linseed, mustard-seed, wheat-flour, etc.
Cayenne pepper is adulterated with red led, vermilion, red ocher, brick-dust, common salt, turmeric, etc.
Mustard is largely adulterated with ordinary and pea flour, linseed meal, and turmeric; and a little chromate of lead is sometimes added to improve the color. Dr. Hassall sub mitted 42 specimens of mustard, to examination; the whole of them contained wheat flour and turmeric.
Ginger is frequently adulterated. Out of 21 samples, Dr. Hassell found that 15 con tained various-kinds of flour, ground rice, Cayenne pepper, mustard husks, and turmeric, which in most cases formed most of the so-called ginger.
Out of 26 samples of mixed spices, 16 were found by Dr. Hassall to contain sago-meal, ground ricefw heat-flour, etc.
Curry powder (q.v.) was found by Dr. Iis,ssall to be very commonly 'adulterated, only 7 specimens out of 26 being genuine. In 8 of the samples, red lead was detected. The frequent use of curries may thus often give rise to the disease known as lead-palsy.
The adulterations of tea, both by the Chinese and in this country, are too numerous for us to mention. See Hassall's Adulterations Detected, pp. 65-104.
Coffee, in its powdered form, is not merely largely adulterated with chicory, but additionally with roasted grain, roots, acorns, sawdust, exhausted tan (termed croats), eoffina (the seeds of a Turkish plant), burnt sugar, and (worst of all) baked horses' and bullocks' liver. In the Quarterly Journal of the Chemical Society for April, 1856, there is an excellent report by Messrs. Graham, Stenhouse, and Campbell on the mode of detecting vegetable substances mixed with coffee. Even whole roasted coffee is not safe
from adulteration, a patent having been actually taken out to mold chicory into the form of coffee-berries.
Cocoa and chocolate arc adulterated with flour, potato-starch, sugar, clarified mutton suet, and various mineral substances, such as chalk, plaster of Paris, red earth, red ocher, and Venetia] earth, the last three being used as coloring matters.
The adulterations of beer, wine, and spirits arc noticed in the articles devoted to those subjects.
Vinegar is adulterated with water, sulphuric acid, burnt sugar, and sometimes with chilies, grains of paradise, and pyroligneous acid. The English law allows one part of sulphuric acid to 1000 of vinegar, with the view of preserving it from decomposition, but Dr. Hassan found that in many cases three or four times the legal amount was present. It appears from evidence taken before the parliamentary committee on adulterations, that arsenic and corrosive sublimate are no uncommon .ingredients in vinegar. In con nection with vinegar we may place pickles. Dr. Massa. analyzed 16 different pickles for copper, and discovered that poisonous metal more or less abundantly in all of them; "in three, in a very considerable quantity; in one, in highly deleterious amount; and in two, in poisonous amount." Preserved fruits and vegetables (especially gooseberries, rhu barb, greengages, and olives) are often also contaminated largely with copper. In these cases, the copper, if in considerable quantity, may be easily detected by placing a piece of polished iron or steel in the suspected liquid for 24 hours, to which we previously add a few drops of nitric acid. The copper will be deposited on the iron. Or ammonia may be added to the fluid in which the pickles or fruit were lying, when, if copper is present, a blue tint is developed. We should he suspicious of all pickles, olives, pre served gooseberries, etc., with a particularly bright green tint.
Milk is usually believed to be liable to numerous adulterations, such as flour, chalk, mashed brains, etc. It appears, however, from Dr. Hassall's researches on London milk, that, as a general rule, water is the only adulteration. The results of the exam inations of 26 samples were, that 12 were genuine, and that 14 were adulterated, the adulteration consisting principally in the addition of water,-the percentages of which varied from 10 to 50 per cent, or one half water. In the article 31mi we shall describe the means of testing the purity of this fluid.
If space permitted, we might extend the list of alimentary substances liable to adulteration to a much greater length. In conclusion, we may remark, that, as a gen eral rule, adulterations of an organic nature, such as flours and starches of various kinds, are best detected by the microscope; while chemical analysis is usually necessary for the detection of mineral adulterations. Dr. Hassall's Adulterations Detected is a perfect cyclopmdia on this subject. See FOOD.