Of the twenty-seven functional categories defined by European Union legislation, Natamycin belongs to preservatives. These are the substances that increase the shelf life of food by protecting it from contamination by microorganisms. Another group of additives that perform a similar role in preserving food for longer periods of time are the antioxidants, which prevent food deteriorating due to oxidation, which is what happens when food is left outdoors.
However, food additives cannot be exchanged or used interchangeably in food.
For example, Natamycin (E-235 according to the nomenclature) is authorised as a preservative for cheese rind and the skin of dried sausages. It acts mainly against moulds and yeasts.
Food additives are always used in a permitted dose that cannot be exceeded.