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How are antioxidants different from antimicrobial food preservatives?

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A woman reads the nutrition labels on two brightly colored boxes of cereal. — food additive Labels provide information on a food product's ingredients and nutritional value.

Antioxidants and antimicrobial agents are both types of food preservatives, but they function through distinct mechanisms to prevent food spoilage.1

Antioxidants
These compounds are used to delay or prevent the deterioration of food caused by oxidative mechanisms. They specifically target autoxidation—a chain reaction where fats and oils react with oxygen to produce rancidity. Antioxidants, such as BHA and BHT, typically function by scavenging free radicals or acting as oxygen scavengers to terminate these oxidative chain reactions.12

Antimicrobial Agents
In contrast, antimicrobials are designed to inhibit the growth of spoilage and pathogenic microorganisms, including bacteria, yeasts, and molds. Their mechanisms of action include disrupting cell membrane functions, inhibiting essential enzymes, or preventing spore germination. Common examples include acetic acid, nitrates, and nisin, which are often used alongside other techniques like refrigeration to ensure food safety.13

While antioxidants protect against chemical degradation, antimicrobials protect against biological threats.14