Whether you're adding some moisture to a classic club sandwich or binding together the ingredients of a tuna salad, mayonnaise is a useful kitchen essential with many applications. Although it's a widely-available provision sold at almost every supermarket in various forms — from sriracha-infused types to vegan iterations — making mayonnaise at home gives you more agency over its flavor, texture, and nutritional makeup. But no matter which type you go for, both packaged and scratch-made mayo are perishable items, which begs the question: Does store-bought mayo spoil faster than homemade? Store-bought mayonnaise actually does not spoil quicker than its homemade counterpart.
In fact, the latter spoils significantly faster than the former. Store-bought mayo is shelf-stable at room temperature for a considerable amount of time (with the exact period varying between products) until it's been opened, after which it can last for up to two months in the refrigerator. On the other hand, homemade mayonnaise should be refrigerated and consumed within four days.
Store-bought mayonnaise lasts longer than homemade because it is usually manufactured with natural and/or chemical preservatives such as citric acid, vinegar, and sorbic and benzoic acid. Supermarket mayo is also made with pasteurized eggs that have been heat-treated to kill harmful bacteria — which further reduces the risk of pathogen contamination or spoilage. Maximizing mayonnaise shelf life Regardless of which type you .
