One can judge of the amount of tin dissolved by the corrosion of the inside of the can.
Reject cans that show much rust around the cap on the inside of the head.
If more than one hole is found soldered in the cap, reject the can. Cans of salmon are the only exception that has come to the author’s notice. A second hole, in general, indicates that decomposition had set in and the can had been punctured and resealed.
CHAPTER VI
FRUITS AND FRUIT PRODUCTS
Salicylic acid, benzoic acid, and saccharin are used to preserve fruits. The last is also added as a sweetener instead of sugar. Many fruit products lose their color with age, and to give them a lasting color they are treated with a coal-tar dye, cochineal, acid magenta, or caramel.
A very small per cent of the jams and jellies sold are strictly pure. These cheap products are made up principally of apple juice and commercial glucose; artificial essences are added to imitate the real flavor.
In cheap jellies made of apple juice and glucose syrup, a “coagulator” is used; usually sulfuric acid and alum, also citric and tartaric acids may be used for this purpose.