Properties of Adulterated Lards.—It is possible to mix together the different materials used in making adulterated lard in such a manner as to produce a compound which in some respects resembles the natural product. This compound, however, necessarily differs from the natural product in its physical and microscopic properties and in its reaction with various chemicals which give distinct color with the different fats and oils used as adulterants. The mean properties of thirteen samples of mixed or compound lards are shown in the following table:
Refractive Rise of Temperature
Specific Gravity. Melting Point. Index. with Sulfuric Acid. Water. Iodin.
35° C. ° C. 25° C. ° C. Percent. Percent.
.9060 40.6 1.4634 46.5 .098 63.58
These lards, in addition to the above properties, show distinct color reaction with sulfuric and nitric acid and with the reagents which are distinctive of cottonseed oil. They are mostly mixtures of lard and tallow stearin with cotton oil or cotton oil stearin.
In addition to the adulterations already mentioned as mixing with cottonseed oil may be added the use of coconut oil. It is not probable that in the United States any adulteration of lard with coconut oil has been made for commercial purposes. Such an adulteration, however, is practiced in some foreign countries. Coconut oil contains considerable quantities of volatile acid, and, therefore, when used as an adulterant of lard, would increase the normal quantity of volatile acid materially. One sample examined by Allen, of England, was found to contain a quantity of coconut oil, amounting to 33 percent.
Summary.—In the preceding pages has been given a description of the character of lard, the sources from which it is made, the method of its preparation, its chemical and physical properties and the common adulterations to which it is subjected. There is no question of the wholesomeness of the usual fats and oils, or parts thereof, which are used in the sophistication of lards. The adulteration is intended solely for fraudulent purposes, that is, to sell under the name of a higher priced article one of a lower price.
There are many persons who prefer to use vegetable oils and fats as substitutes for lard in all cases. It is only fair to the consumer that the character of a fat and oil, however, for edible purposes be plainly made known to the purchaser. He is then to judge of the propriety or impropriety of using the articles in question. It seems quite certain that the use of vegetable oils and fats will be greatly increased in this country. All hygienists grant that they are at least equally as wholesome as the animal fat and oil. They are certainly less open to suspicion as having been derived from diseased sources. As a rule, they are carefully expressed and properly refined, free from rancidity and from any mechanical or chemical constituents which render them
