Preservative

A (food) additive which retards spoilage, putrefaction, or other undesirable chemical changes in a substance.

Common food preservatives are salt, BHA, BHT, sodium nitrate, sodium nitrite, sulfites (sulfur dioxide, sodium bisulfate, potassium bisulfate...), disodum EDTA.

The relative benefits of artificial food additives (including preservatives) are the subjects of intense debate among dieticians.

Other preservatives include formaldehyde? (usually in solution), glutaraldehyde, ethanol, methylchloroisothiazolinone, and freeze drying.