A preservative is a natural or synthetic chemical that is added to products such as foods, pharmaceuticals, paints, biological samples, wood, etc. to prevent
decompositionby microbial growth or by undesirable chemical changes.
Preservatives in wood
Preservatives may be added to
woodto prevent the growth of fungias well as to repel insects and termites. Typically arsenic, copper, chromium, borate, and petroleumbased chemical compounds are used. For more information on wood preservatives, see timber treatment, lumber, and creosote.
Preservatives in foods
food additives can be used alone or in conjunction with other methods of food preservation. Preservatives may be "anti-microbial preservatives", which inhibit the growth of bacteria and fungi, or " antioxidants" such as oxygen absorbers, which inhibit the oxidationof food constituents. Common anti-microbial preservatives include calcium propionate, sodium nitrate, sodium nitrite, sulfites ( sulfur dioxide, sodium bisulfite, potassium hydrogen sulfite, etc.) and disodium EDTA. Antioxidants include BHAand BHT. Other preservatives include formaldehyde(usually in solution), glutaraldehyde(kills insects), ethanoland methylchloroisothiazolinone. The benefits and safety of many artificial food additives (including preservatives) are the subject of debate among academicsand regulators specializing in food scienceand toxicology.
Natural food preservation
Natural substances such as salt,
sugar, vinegar, and diatomaceous earthare also used as traditional preservatives. Certain processes such as freezing, pickling, smoking and salting can also be used to preserve food. Another group of preservatives targets enzymes in fruits and vegetables that continue to metabolize after they are cut. For instance, citric and ascorbic acids from lemonor other citrusjuice can inhibit the action of the enzyme phenolasewhich turns surfaces of cut apples and potatoes brown. Caution must be taken, however, since FDA standards do not currently require fruit and vegetable product labels to accurately reflect the type of preservative used in the products. Further, there is no current regulation requiring the inclusion of preservative chemical in labels at all; some potentially hazardous.
Some modern synthetic preservatives have become controversial because they have been shown to cause respiratory or other health problems. Some studies point to synthetic preservatives and artificial coloring agents aggravating ADD & ADHD symptoms in those affected. [“Food additives and hyperactive behaviour in 3-year-old and 8/9-year-old children in the community: a randomized, double-blinded, placebo-controlled trial”, "The Lancet", Sept 2007] [1997 Graduate Student Research Project conducted at the University of South Florida. Richard W. Pressinger M.Ed.] Older studies were inconclusive quite possibly due to inadequate clinical methods of measuring offending behavior. Parental reports were more accurate indicators of the presence of additives than clinical tests. ["Food Additives May Affect Kids' Hyperactivity", "WebMD Medical News", May 24, 2004] Several major studies show academic performance increased and disciplinary problems decreased in large non-ADD student populations when artificial ingredients, including preservatives were eliminated from school food programs. ["A different kind of school lunch", "PURE FACTS", October 2002] [The impact of a low food additive and sucrose diet on academic performance in 803 New York City public schools, Schoenthaler SJ, Doraz WE, Wakefield JA, "Int J Biosocial Res.", 1986, 8(2); 185-195] Allergenic preservatives in food or medicine can cause anaphylactic shock in susceptible individuals, a condition which is often fatal within minutes without emergency treatment.
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preservative — (adj.) late 14c., from M.Fr. preservatif, from M.L. praeservativus, from praeservare (see PRESERVE (Cf. preserve) (v.)). The noun is from early 15c., a preservative medication. Sense of chemical added to foods to keep them from rotting is from… … Etymology dictionary
Preservative — Pre*serv a*tive, a. [Cf. F. pr[ e]servatif.] Having the power or quality of preserving; tending to preserve, or to keep from injury, decay, etc. [1913 Webster] … The Collaborative International Dictionary of English
Preservative — Pre*serv a*tive, n. That which preserves, or has the power of preserving; a presevative agent. [1913 Webster] To wear tablets as preservatives against the plague. Bacon. [1913 Webster] … The Collaborative International Dictionary of English
preservative — index preventive, prophylactic, protective Burton s Legal Thesaurus. William C. Burton. 2006 … Law dictionary
preservative — ► NOUN ▪ a substance used to preserve foodstuffs or other materials against decay. ► ADJECTIVE ▪ acting to preserve something … English terms dictionary
preservative — [prē zʉrv′ə tiv, prizʉrv′ə tiv] adj. [ME preseruatyve < MFr preservatif < ML praeservativus] having the quality of preserving n. anything that preserves; esp., a substance added to a food to keep it from spoiling … English World dictionary
preservative — UK [prɪˈzɜː(r)vətɪv] / US [prɪˈzɜrvətɪv] noun [countable/uncountable] Word forms preservative : singular preservative plural preservatives chemistry a chemical substance used for preventing food or wood from decaying wood preservative This drink… … English dictionary
preservative — noun ADJECTIVE ▪ food, wood ▪ artificial, chemical, synthetic ▪ Our products contain no artificial preservatives. VERB + PRESERVATIVE … Collocations dictionary
preservative — n. a food preservative * * * [prɪ zɜːvətɪv] a food preservative … Combinatory dictionary
preservative — [[t]prɪzɜ͟ː(r)vətɪv[/t]] preservatives N MASS A preservative is a chemical that prevents things from decaying. Some preservatives are added to food, and others are used to treat wood or metal. Nitrates are used as preservatives in food… … English dictionary