Narrow earth band on the outer wall of a defensive ditch.
A chemical compound that is added to protect against decay or decomposition.
Substance (additive) added to a food in order to inhibit the growth of bacteria, yeasts, molds, and other microorganisms, and therefore extend its shelf life. The term sometimes refers to antioxidants (substances added to oils and fats to prevent their becoming rancid) as well. All preservatives are potentially damaging to health if eaten in sufficient quantity. Both the amount used, and the foods in which they can be used, are restricted by law.
Alternatives to preservatives include faster turnover of food stocks, refrigeration, better hygiene in preparation, sterilization, and pasteurization (see food technology).