FOOD ADDITIVE

any of various chemical substances added to foods to produce specific desirable effects. Additives such as salt, spices, and sulfites have been used since ancient times to preserve foods and make them more palatable. With the increased processing of foods in the 20th century, there came a need for both the greater use of and new types of food additives. Many modern products, such as low-calorie, snack, and ready-to-eat convenience foods, would not be possible without food additives. Food additives and their metabolites are subjected to rigorous toxicological analysis prior to their approval for use in the industry. Feeding studies are carried out using animal species (e.g., rats, mice, dogs) in order to determine the possible acute, short-term and long-term toxic effects of these chemicals. These studies monitor the effects of the compounds on the behaviour, growth, mortality, blood chemistry, organs, reproduction, offspring, and tumour development in the test animals over a 90-day to two-year period. The lowest level of additive producing no toxicological effects is termed the no-effect level (NOEL). The NOEL is generally divided by 100 to determine a maximum acceptable daily intake (ADI). There are four general categories of food additives: nutritional additives, processing agents, preservatives, and sensory agents. These are not strict classifications, as many additives fall into more than one category. For more information on additives, see emulsifier; food colouring; nutritional supplement; and preservative. Additional reading R. MacRae, R.K. Robinson, and M.J. Sadler (eds.), Encyclopaedia of Food Science, Food Technology, and Nutrition, 8 vol. (1993); and Y.H. Hui (ed.), Encyclopedia of Food Science and Technology, 4 vol. (1992), are general works that cover all aspects of the science of food. P. Fellows, Food Processing Technology: Principles and Practices (1988), is an introductory text. R. Paul Singh A. Larry Branen, P. Michael Davidson, and Seppo Salminen (eds.), Food Additives (1990), treats all aspects of the subject. Thomas E. Furia (ed.), CRC Handbook of Food Additives, 2nd ed., 2 vol. (1972, reissued 1980), contains a classification and description of the compounds used as food additives, as well as commercial forms, functions, applications, stability, and regulatory status of individual agents. Joseph A. Maga and Anthony T. Tu (eds.), Food Additive Toxicology (1995), discusses toxicological aspects. Tim Smith (ed.), Food Additive User's Handbook (1991), provides tables containing data on the functions, characteristics, processing stability, and applications of specific food additives. P. Michael Davidson