A food preservative is a substance added to food products to prevent or slow spoilage caused by microbial growth, enzymatic activity, or chemical changes such as oxidation.
Preservatives are classified into two main categories: antimicrobial agents, which inhibit the growth of bacteria, yeasts, or molds (e.g., sodium benzoate, potassium sorbate, and nitrates), and antioxidants, which prevent oxidation and rancidity (e.g., ascorbic acid and BHT (butylated hydroxytoluene)).