G06: Sciences - Physical and Chemical Changes: Chemical Methods

Many types of additives are used to make your food last longer. Some are synthesized in the laboratory while others occur naturally. Preservatives can be categorized into three main groups. Antimicrobials work through stopping the growth of molds, bacteria, and yeast hence keep your food fresh longer. Antioxidants work by slowing down the oxidation of fats, a process that turns food rancid. The third class of preservatives exerts their effects by inhibiting rot in produce.

Salt is used in two primary ways to preserve foods, either in granule form or in brine, which is a salt-and-water solution.

Sugar has some unique properties that mean it can preserve food. It is used in jams, jellies, conserves, relishes, chutneys, cures and all sorts of processes that help to prevent food from spoiling.

To put it simply, fermentation is a bioprocess that utilizes microorganisms such as bacteria and fungi (yeasts and molds) to produce either alcohol or acid from carbohydrate sources. These metabolites preserve products and create unique flavors, textures and enhanced nutrition. Fermentation generally occurs in an anaerobic environment, meaning no oxygen is present.

For centuries, ingredients have served useful functions in a variety of foods. Our ancestors used salt to preserve meats and fish, added herbs and spices to improve the flavor of foods, preserved fruit with sugar, and pickled cucumbers in a vinegar solution. Today, consumers demand and enjoy a food supply that is flavorful, nutritious, safe, convenient, colorful and affordable. Food additives and advances in technology help make that possible.