An odour or flavour foreign to a product. The distinguishing feature of a taint, as distinct from off-flavour/ odour, is that the chemical responsible for the taint is not produced in the product, but comes from its surroundings. Taints often have an unpleasant character, but that is not a necessary condition for taint. In the case of fish in the aquatic environment, taints are acquired from the ambient water. Examples are the earthy/muddy taints in freshwater fish and oily taints in fish exposed to petroleum or petroleum products. Products can be tainted by strong smelling chemicals such as phenolic disinfectants in the ambient air. See off-flavour/odour.