The use of preservatives other than traditional oils, salts, paints, etc. in food began in the late 19th century, but was not widespread until the 20th century.

When were food additives first used?

The 1958 Food Additives Amendment to the Federal Food, Drug, and Cosmetic Act provided for the first specific regulations of food additives. Approval of new food additives was required before they could be marketed, and the responsibility for proving their safety was placed on the manufacturer.

When did they start putting chemicals in food?

By the 1930s, a variety of agrochemicals were commonly used, and food additives were becoming common in processed foods. During the 1940s and 1950s advances were made in toxicology, and more systematic approaches were adopted for evaluating the safety of chemical contaminants in food.