Nisin is approved for use, to varying degrees, as a component of the preservation procedure for pro cessed and fresh cheese, canned foods, processed vegetables and baby foods, in up to 50 countries (Hurst, 1981; Delves-Broughton, 1990; De Vuyst and Vandamme, 1994b). Typical levels that are used in foods range between 2.5 and 100 ppm. It is most stable in high-acid foods.