Preservatives

A preservative is a naturally occurring or synthetically produced substance that is added to products such as foods, pharmaceuticals, paints, biological samples, wood, etc. to prevent decomposition by microbial growth or by undesirable chemical changes. Preservatives can be divided into two types, depending on their origin. Class I preservatives refers to those preservatives which are naturally occurring, everyday substances. Examples include salt, honey and wood smoke. Class II preservatives refer to preservatives which are synthetically manufactured.