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How Long Can Mayonnaise Sit Out?

Mayonnaise has long been a staple condiment in many households, adding a creamy touch to sandwiches, salads, and various recipes. However, there has always been a debate surrounding the need for refrigeration regarding mayonnaise. The primary concern revolves around raw eggs in mayonnaise and the potential risks associated with leaving it at room temperature.

So, how long can mayonnaise be left out of the fridge? Keep reading to learn more.

How Long Can Mayonnaise Sit Out?

Mayonnaise should not remain out for more than 8 hours before refrigerating it. While some argue that the preservatives in commercially produced mayonnaise eliminate the need for refrigeration, this is not entirely accurate. While preservatives can extend the shelf life of mayonnaise, they do not eradicate the need for proper storage.

Unopened mayonnaise can be safely stored in a cool, dark cupboard until expiration. However, once opened, it is crucial to keep mayonnaise refrigerated to maintain its freshness and prevent the growth of harmful bacteria.

Safety of Consuming Mayonnaise Left Out Overnight

Mayonnaise left at room temperature overnight should not be consumed. Extended exposure to temperatures between 40 and 140 degrees Fahrenheit creates an ideal environment for bacterial growth, increasing the risk of foodborne illnesses. Even if the mayonnaise does not exhibit immediate signs of spoilage, leaving it out for extended periods significantly shortens its shelf life.

Bacterial growth in mayonnaise can lead to the production of toxins that may not be detectable by sight or smell. Therefore, it is essential to prioritize food safety and avoid consuming mayonnaise left out overnight or for extended periods.

How Long Will Mayonnaise Last in the Fridge?

Properly stored mayonnaise can last two to three months in the refrigerator. However, it is essential to note that leaving mayonnaise out at room temperature, even for a short period, reduces its overall shelf life. When mayonnaise is repeatedly exposed to temperature fluctuations, its quality deteriorates, and the risk of spoilage increases.

Additionally, contamination from other foods, such as using the same knife for spreading mayonnaise and touching raw meat, can introduce harmful bacteria to the jar. This can further decrease the storage time of mayonnaise in the fridge.

How Long Will Mayonnaise Last in a Cool Cupboard?

If unopened, mayonnaise can be stored in a cool cupboard until its expiration date. However, once opened, mayonnaise in a cool cabinet has a limited shelf life of approximately eight hours. Bacterial growth can occur even at temperatures above 50 degrees Fahrenheit, making refrigeration the preferred method for keeping mayonnaise fresh and safe for consumption.

Signs of Spoiled Mayonnaise

It is crucial to be able to identify signs of spoiled mayonnaise to avoid the risks associated with consuming it. Visual indicators include mold growth, discoloration, or separation of the ingredients. If the mayonnaise smells off or has a sour odor, it is another strong indication of spoilage.

Caution should always be exercised when consuming mayonnaise that shows signs of spoilage, as it may contain harmful bacteria or toxins that can cause food poisoning.

Potential Hazards of Consuming Spoiled Mayonnaise

Eating spoiled mayonnaise can pose significant health risks. The primary concern lies in the use of raw eggs in mayonnaise production. As eggs can potentially contain Salmonella bacteria, consuming spoiled mayonnaise increases the likelihood of food poisoning.

Food poisoning from contaminated mayonnaise may lead to symptoms including nausea, vomiting, diarrhea, abdominal pain, and fever. In severe cases, it can lead to dehydration and require medical attention. It is crucial to exercise caution and avoid consuming mayonnaise that has gone bad.

How Long Can Homemade Mayonnaise Sit Out?

Homemade mayonnaise should always be included at room temperature for extended periods. Unlike commercially produced mayonnaise, homemade versions often do not contain preservatives, making them more susceptible to bacterial growth.

Moreover, homemade mayonnaise typically incorporates raw eggs, increasing the risk of Salmonella contamination. Due to these factors, homemade mayonnaise must be promptly refrigerated to ensure food safety. Its shorter shelf life compared to commercial mayonnaise further emphasizes the importance of proper storage and refrigeration.


In conclusion, mayonnaise can be left out of the fridge for up to eight hours. However, refrigeration is strongly recommended to maintain freshness and prevent bacterial growth. It is essential to follow general guidelines for refrigeration of other perishable foods to ensure food safety.

Proper storage and refrigeration of mayonnaise are crucial steps to avoid the risks associated with consuming spoiled or contaminated products. By prioritizing food safety and adhering to recommended storage practices, you can enjoy mayonnaise while minimizing the potential for foodborne illnesses.

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