Mayonnaise is a kitchen staple. Many households use it as a condiment or as an ingredient in recipes. But questions often arise: should it stay in the fridge or can it sit on the counter? This matters because improper storage can lead to foodborne illnesses. Knowing how to store mayonnaise properly ensures safety and preserves its quality.

The Science Behind Mayonnaise
Mayonnaise is an emulsion of oil, egg yolks, and an acid like vinegar or lemon juice. Egg yolks contain lecithin, which stabilizes the mixture. Commercial mayonnaise usually adds preservatives and pasteurized eggs, which extend its shelf life. Homemade mayonnaise lacks these safeguards, making it more prone to spoilage.

Acidity in mayonnaise slows bacterial growth, but it’s not foolproof. Leaving it out at room temperature for too long can still be risky.

Why Temperature Matters
Temperature plays a critical role in mayonnaise safety. At room temperature, bacteria multiply quickly. Refrigeration slows this growth, keeping the mayonnaise safe longer. For best results, store mayonnaise below 40°F (4°C).