How do acetic acid, benzoic acid, and sorbic acid act against microorganisms?

Acetic acid, benzoic acid, and sorbic acid are organic acids used as antimicrobial agents to inhibit the growth of spoilage and pathogenic microorganisms in food. These preservatives are most effective in products with a low pH.1

Their specific mechanisms of action against microorganisms are summarized below:

| Chemical Agent | Mechanism of Action | Target Microorganisms |
| :--- | :--- | :--- |
| Acetic acid | Disrupts cell membrane function | Bacteria, yeasts, and some molds2|
| Benzoic acid | Disrupts cell membrane function and inhibits enzymes | Molds, yeasts, and some bacteria2|
| Sorbic acid | Disrupts cell membrane function, inhibits enzymes, and inhibits bacterial spore germination | Yeasts, molds, and some bacteria2|

For benzoic acid specifically, the free acid is the active agent, which is why it must be used in an acid medium to be effective. These preservatives are often used in conjunction with other techniques, such as refrigeration, to ensure food safety and quality.31