—The canning of mushrooms is an industry of large magnitude, especially in France. The young, unexpanded mushrooms in the form of buttons are those which are usually subjected to the canning process. Mushrooms are brought to the factory where they are cleaned and scraped, the stem cut to a proper length, thoroughly washed in several washings of clean water, and taken to a sulfuring furnace where they are exposed to the fumes of burning sulfur for some time. The purpose of this treatment is to bleach the mushroom and make it as white as possible. Decayed or deformed buttons are not included in the cans of highest quality. The prepared mushrooms are then placed in cans, usually of tin, and preserved by subjecting them to a temperature at or above boiling water until thoroughly sterilized.
Canned Pieces and Stems of Mushrooms.
—The imperfect portions, the pieces which are cut away, and other fragments of the mushroom, resulting from the preparation of the product described above, are treated practically in the same manner for sterilizing purposes and are sold to the trade under various names, the most common of which is Champignons d’Hotel. They also frequently appear under the name of Champignon Choix and other deceptive labels.
Adulteration of Mushrooms.
—There is no adulteration practiced of fresh mushrooms unless the occasional occurrence of poisonous varieties may be so considered. It is evident, however, that the introduction of poisonous varieties is the result of carelessness or mistake and not for any purpose. Nevertheless a most exacting supervision over the preparation of fresh mushrooms for the market should be required, and any failure to exercise this care may be considered as resulting in adulteration or depreciation of the character of the product.
In canned mushrooms the presence of sulfurous acid may be regarded as an adulterant, and such a substance, believed to be inimical to health, is not necessary in the preparation of the goods. It is quite certain that the public taste would soon adapt itself to an amber- or brown-colored product in canned mushrooms and value it as highly as the buttons which are white. Since the sole purpose of the use of sulfur is for bleaching, the end secured scarcely justifies the means. It is claimed, naturally, that the use of sulfur is also a safeguard in securing a better keeping of the product, but such an adjunct for keeping purposes is only necessary when the sterilization is not complete. It is to be hoped that the day will soon come when mushrooms bleached with sulfurous acid shall no longer be found upon our market. The use of other preservatives than sulfurous acid has at times been practiced, but it is not believed that there are many cans of mushrooms offered upon the market which contain any chemical preservatives whatever save the sulfurous acid above noted. Since the canned mushrooms are valued principally as a condiment, the inclusion of imperfect or partially decayed or malformed buttons is extremely unusual. The buttons are separated into sizes of approximately the same magnitude, so that a can of the product is uniform in size as well as in quality. The customer may be reasonably certain that he is getting a good, young, carefully selected product, free from disease and from accidental impurities which might render the product unwholesome or unpalatable.
Truffles.
—The truffle has been known almost, if not quite as long as the mushroom as an edible delicacy. The use of truffles in France became very common during the 14th century, but on account of their high price they remained for a long time a luxury and not a general article of commerce. It is only within the 19th century, after 1840, that their consumption became general. The truffle belongs to the botanical family Tuberaceæ.
The propagation of truffles is similar to that of mushrooms, by spores, which first give rise to a mycelium which by further condensation forms the body of the truffle. This mycelium furnishes the nutritients for the tubercle during a certain time of its early growth. In the cultivation of the truffle, artificially, it is necessary to make use of a forest or other similar artificial covering. If trees are planted especially for the development of truffles it requires six or eight years growth before the cultivation of truffles is successful. The truffle grows very readily in the shade of nut-bearing trees and in the shade of the oak. The mycelium does not produce truffles until after several years of vegetation. When it once begins to fructify and produce the truffle it continues to bear for many years. The truffle, like the mushroom, grows rapidly. At first, as has already been stated, it is nourished by the mycelium, but when this is exhausted it is nourished by absorbing the nutritious elements from the soil and air. When it reaches maturity and its spores are well formed the truffle acquires its maximum of aroma and palatability. After it has reached maturity it can remain a certain time in the soil without being changed. However, after a time it is rapidly decomposed and its tissues become the seat of various chemical reactions or it is devoured by insects.