Copper sulphate is but one of a host of chemical substances applied to various foods for the purpose of altering the color which the foods would otherwise possess. In some cases perhaps it may be the general opinion that by special treatment the attractiveness of a food product is increased, as when dark-colored flour is bleached white with nitrogen peroxide, but in many instances the modification of color is based on preposterously artificial standards. The use of poisonous aniline dyes for staining candies all the colors of the rainbow must be defended, if at all, on aesthetic rather than on sanitary grounds. Some coloring matters in common use, such as the annatto, universally employed in coloring butter, are believed to be without harmful effect, but others are to be viewed with suspicion, and still others, like copper sulphate, are unquestionably dangerous. The whole practice of food coloration at its best involves waste and may entail serious danger to health. Broadly speaking, all modification of the natural color of foodstuffs is based on an idle convention and should be prohibited in the interest of the public welfare. Bleached flour, stained butter, dyed jelly and ice-cream are no whit more desirable as foods than the natural untreated substances; in fact, they are essentially less desirable. If the whole process of food coloration were known to the public, artificially colored foods would not be especially appetizing. Economically the practice is singularly futile. The artificial whitening of flour with the highly poisonous nitrogen peroxide seems hardly worth the extra tax of fifty cents to a dollar a barrel. Such bleaching with a poisonous gas certainly does not improve the nutritive or digestive qualities of flour; it may be insidiously injurious. The solution of the problem of food coloration seems to lie in a policy of educational enlightenment which shall make natural foods appear more desirable than those sold under false colors. Custom, however, buttressed by skilful advertising, offers a difficult barrier to reform in this field.
FOOD PRESERVATIVES
It is not only legitimate, but in every way most desirable, to keep food over from a season of superabundance to a season of scarcity. From time immemorial food has been preserved by drying, smoking, or salting, and, in modern times, by refrigeration and by heat (canning). These latter methods have come to play a large part in the food habits of civilized communities. Since food spoils because of microbic action, all methods of preservation are based upon the destruction of the microbes or the restraint of their growth by various physical and chemical agencies. The use of certain chemical preservatives such as strong sugar and salt solutions, saltpeter brines, and acid pickles has long been known and countenanced. In recent times the employment of chemical preservatives has acquired a new aspect through the increasing tendency of manufacturers to add to food products antiseptic chemicals in wide variety and of dubious physiological effect.
It is not so easy and simple as it might appear to declare that no substance that is poisonous shall be added to food. The scientific conception of a poison is one involving the amount as well as the kind of substance. Common salt itself is poisonous in large doses, but, as everyone knows, small amounts are not only not injurious, but absolutely necessary to health. Well-known and very powerful protoplasmic poisons such as strychnine and quinine are frequently administered in minute doses for medicinal purposes, without causing serious results.
How complicated the question of using food preservatives really is appears in the case of smoked meats and fish, which owe their keeping qualities to the creosote and other substances with which they are impregnated by the smoke. Although these substances are much more highly poisonous than chemical preservatives like benzoic acid, over which much concern has been expressed, but little if any objection has been made to the use of smoked foods.
The use of benzoic acid (benzoate of soda) as a food preservative illustrates several phases of the controversy. Observations by Wiley in 1908 upon so-called "poison squads" were thought by him to indicate that benzoate of soda administered with food led to "a very serious disturbance of the metabolic functions, attended with injury to digestion and health." On the other hand, the experiments of the Referee Board of Scientific Experts (1909), conducted with at least equal care and thoroughness, were considered to warrant the conclusions that:
(1) Sodium benzoate in small doses (under five-tenths of a gram per day) mixed with the food is without deleterious or poisonous action and is not injurious to health. (2) Sodium benzoate in large doses (up to four grams per day) mixed with the food has not been found to exert any deleterious effect on the general health, nor to act as a poison in the general acceptance of the term. In some directions there were slight modifications in certain physiological processes, the exact significance of which modification is not known. (3) The admixture of sodium benzoate with food in small or large doses has not been found to injuriously affect or impair the quality or nutritive value of such food.
Still later experiments under the auspices of the German government (1913) showed that in the case of dogs and rabbits relatively large doses of benzoic acid (corresponding to sixty to one hundred grams per day for a man weighing one hundred and fifty pounds) were necessary in order to produce demonstrable effects of any kind. This finding may be considered to confirm in a general way the finding of the Referee Board that four grams per day is harmless.
Probably the evidence respecting the effect of benzoic acids and the benzoates when used as food preservatives constitutes as favorable a case as can be made out at the present time for the employment of any chemical substance. Benzoic acid is present in noteworthy amounts in many fruits and berries, especially cranberries, and its presence in these natural foods has never been connected with any injurious action. In point of fact, substances present in many ordinary foodstuffs are converted within the human body first into benzoic acid and then into hippuric acid. Folin's masterly summing up is worth quoting:
We know that the human organism is prepared to take care of and render harmless those small quantities of benzoic acid and benzoic acid compounds which occur in food products or which are formed within the body; we know how this is accomplished and are reasonably sure as to the particular organ which does it. We also know that the mechanism by means of which the poisonous benzoic acid is converted into the harmless hippuric acid is an extremely efficient one, and that it is capable of taking care of relatively enormous quantities of benzoic acid. In this case, as in a great many others, the normal animal organism is abundantly capable of performing the function which it must regularly perform in order to survive. From this point of view it can be argued, and it has been argued with considerable force, that the human organism is abundantly capable of rendering harmless reasonable amounts of benzoic acid or benzoate which are added for purposes of preservation to certain articles of our food. In my opinion this point of view is going to prevail, and the strife will resolve itself into a controversy over how much benzoic acid shall be permitted to go into our daily food.