Preservative

A preservative is a substance added to foods, cosmetics, medicines, and other perishable products to slow spoilage by inhibiting microbial growth, retarding oxidation, or both. Preservatives may be synthetic chemicals or natural extracts. In foods, they reduce spoilage caused by bacteria, yeasts, and molds and can prevent enzymatic browning. Common chemical food preservatives include benzoates (sodium benzoate), sorbates (potassium sorbate), nitrites, sulfites, and various organic acids. Parabens are used in some products. Antimicrobial action often involves lowering pH, disrupting cell membranes, or interfering with metabolism; antioxidants such as ascorbic acid and tocopherols help preserve by preventing oxidation but are not strictly antimicrobial preservatives.

In cosmetics and personal care, preservatives prevent microbial contamination during use and storage. Examples include phenoxyethanol, parabens (where allowed), benzyl alcohol, and formaldehyde-releasing agents. In pharmaceuticals, preservatives maintain sterility and product stability.

Safety and regulation: Preservatives are subject to safety assessments and permitted-use limits by authorities such as the FDA and EFSA, and by Codex Alimentarius. Labeling is typically required. Some preservatives can cause allergies or sensitivities; others have raised safety concerns, leading to restricted use or the development of alternatives in some markets.

Natural preservation methods include salt, sugar, vinegar, fermentation, and plant extracts such as essential oils. The choice of preservative depends on product type, desired shelf life, regulatory requirements, and consumer preferences.