This booklet presents a brief survey of the gradual evolution of man's efforts to preserve his food. The story is presented in a simple manner that should appeal to all types of readers. As a basis for understanding the forces which must be combated if food is to be preserved, some discussion is given at first to the principal factors responsible for food spoilage. The action of microscopic agents such as bacteria and molds accounts for by far the greatest amount of food loss.
In the early days of our civilization, man used the means which were at hand for preserving his foods. This was simple storage in clean containers, sometimes aided by low temperature. Such methods were inadequate and suitable only for foods with natural keeping qualities. Then, so far back that no one knows their origin, came the use of such means of preservation as spices, wood smoke