Preservatives used specifically in foods: substances that inhibit microbial spoilage or chemical deterioration to extend shelf life. Examples include sorbates, benzoates, sulphites and nitrites, each with permitted maximum levels and conditions of use set by food-additive regulations; natural options include salt, sugar and vinegar. They act by disrupting microbial membranes (sorbic acid), blocking enzyme systems (sulphites) or inhibiting Clostridium botulinum (nitrites in cured meats); hurdle technology combines them with pH, water activity and heat for milder preservation. Consumer resistance drives ‘no added preservative’ formulations relying on fermentation, high pressure or natural antimicrobials such as nisin and cultured dextrose.