Food Poisoning

by Edwin O. Jordan

Although diseased conditions due to the absence rather than the presence of certain constituents in the food are not perhaps to be properly classed as food poisoning, they may be mentioned here to illustrate the complexity of the food problem. At least one disease,—pellagra—is attributed by some observers to the presence of an injurious substance or micro-organism in the food, and by others to the absence of certain ingredients necessary to the proper maintenance of life.

Beriberi.—One of the best established instances of a disease due to a one-sided or defective diet is beriberi. This affection is prevalent among those peoples subsisting chiefly or wholly on a diet of rice prepared in a certain way. As a matter of trade convention milled white rice has long been considered superior to the unpolished grain. The process of polishing rice by machinery removes the red husk or pericarp of the grain, and a diet based almost exclusively on polished rice causes this well-marked disease—beriberi—which was for long regarded as of an infectious nature.[116] It has been shown that if the husks are restored to the polished grain and the mixture used as food the disease fails to develop. Experiments upon chickens and pigeons show that an exclusive diet of white rice causes in these animals a disease (polyneuritis of fowls) similar to beriberi, which likewise can be arrested or prevented by a change in diet. From such observations the conclusion has been drawn that in the pericarp of the rice grain there are certain substances essential to the maintenance of health and that their withdrawal from the diet leads to nutritional disturbances. The name "vitamin" has been given to these substances, but little is known about their chemical or physiological nature. In a varied diet vitamins are presumably present in a variety of foodstuffs, but if the diet is greatly restricted, some apparently trivial treatment of the food may result in their elimination. It is uncertain how many and how various the substances are that have been classed by some writers under the designation vitamin. At least two "determinants" are thought to be concerned in the nutrition of growth, a fat-soluble and a water-soluble substance.[117]

Pellagra is one of the diseases attributed to an unbalanced diet,[118] and it has been suggested that the increased use of highly milled maize and wheat flour from which vitamins are absent may be responsible for the extension of this malady in recent years. Other observers, while admitting that a faulty diet may predispose to pellagra as to tuberculosis and other diseases, do not assent to the view that it is the primary factor.[119]

Lathyrism.—The name lathyrism has been given to a disease supposed to be connected with the use of the pulse and the chick pea. Nervous symptoms are conspicuous and sometimes severe, although the affection is of a milder type than pellagra. The disease is said to be associated with the exclusive or almost exclusive use of leguminous food and with generally miserable conditions of living. It is yet uncertain whether lathyrism is a deficiency disease like beriberi and possibly pellagra, or whether it is due to a mixture of foreign and poisonous seeds with the particular legumes consumed, or whether under certain conditions the legumes themselves may contain poisonous substances generated by some unknown fungus growths.

Favism (from fava, "bean") is an acute febrile anemia with jaundice and hemoglobinuria which occurs in Italy and has been attributed to the use of beans as food or even to smelling the blossom of the bean plant.[120] A marked individual predisposition to the malady is said to exist. Although the symptoms are very severe and seem to point to an acute poisoning, no toxic substance has been isolated from the implicated beans. It has been suggested by some that bacterial infection, and by others that a fungous growth on the bean, is responsible, but no evidence has been brought forward to support either assumption.

Scurvy in some forms is undoubtedly connected with the lack of certain necessary components of a normal diet. The development of scurvy on shipboard in the absence of fresh milk, fresh vegetables, fruit juice, and the like is a fact long familiar. Guinea-pigs fed on milk, raw and heated, and on milk and grain have developed typical symptoms of scurvy.[121] On the other hand, a form of experimental scurvy has been produced in guinea-pigs and rabbits kept on an ordinary diet of green vegetables, hay, and oats by the intravenous injection of certain streptococci.[122] The relative share of diet and infection in the production of human scurvy is consequently regarded by some investigators as uncertain.

Rachitis or rickets is a pathological condition in some way connected with a protracted disturbance of digestion which in turn leads to faulty calcium metabolism. It does not seem probable that rickets is caused by too little calcium in the food, but rather by the inability of the bone tissue to utilize the calcium brought to it in the body fluids. Experiments upon the causation of the disease have not given uniform results, and it does not seem possible at present to place responsibility for this condition upon any particular form of diet, such as deficiency of fat or excess of carbohydrates or protein. It appears to be true that the prolonged use of any food leading to nutritional disturbance causes an inability on the part of the bone cells to take up calcium salts in the normal manner.

While there are many obscure points with regard to the origin of both scurvy and rickets, there is no doubt that some dietary shortcoming lies at their base, and that they can be cured or altogether avoided by maintenance of suitable nutritional conditions.

THE FOODS MOST COMMONLY POISONOUS

Certain articles of food figure with special frequency in the reports of food poisoning outbreaks. It is not clear in all cases why this special liability to inflict injury exists. For an example, vanilla ice-cream and vanilla puddings have been so often implicated that some investigators have not hesitated to ascribe a poisonous quality to the vanilla itself. But there is no good evidence that this is the case, and it has been suggested that the reducing action of the vanilla favors the growth of anaërobic bacteria which produce poisonous substances, an explanation highly conjectural.