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Mayo Left Out Overnight – Safe To Eat Or Throw Away?

Norah Clark

Is authentic, homemade mayonnaise left out overnight still okay to eat? It all is contingent on how long overnight you have left the mayonnaise out for. If mayo had been left on the table for 12+ hours, throw it out. If it was eight hours or less, you should be fine storing or eating it.

Everyone loves this condiment on their sandwiches and on burgers.

Have you ever used your most loved condiment, such as mayonnaise, mustard, and then forgotten to store it in the refrigerator?

The next question is should you throw it away or throw it back in the refrigerator? Every condiment is different, and some people aren’t willing to put to throw money away.

Read on for further information on whether mayo you have is still delicious after sitting on the counter top for over 12 hours or can you become sick.

What’s In Mayonnaise?

Most condiments could be good after a day on the counter, but mayonnaise is unique.

The components in homemade mayonnaise cause us to be slightly more careful to refrigerate it quickly.

This only applies to authentic mayonnaise, which has eggs in its main ingredients. The FDA has a precise definition of what authentic mayonnaise is.

Mayonnaise that is real from eggs that have been boiled. When using eggs as a component, you must be aware of the risk of salmonella poisoning if the food is not taken care of properly.

Mayonnaise is mostly eggs, but it also contains some lemon juice, vinegar, and salt. The lemon juice and vinegar assist in keeping eggs from going off inside a sealed container.

The official statement from the FDA is that authentic mayonnaise should not be kept at room temperature longer than 8 hours.

If the temperature is higher than ambient temperature, the length of time is greatly decreased since warm temperatures provide a fertile food source for bacteria.

What’s The Difference Between Store-bought and Authentic Mayonnaise?

Mayonnaise purchased at the store is pasteurized, then transformed before being sealed and delivered to customers at the grocery store. The eggs are also pasteurized, which means you’re given some freedom in the timing.

If mayonnaise has been sealed at the grocery store, it doesn’t need to be kept in the fridge. If you open the seal off of the mayonnaise, it's best to refrigerate it. However, if you neglect to place it back into the refrigerator, the most effective guideline is that the mayonnaise will remain good for around 8 hours at room temperature.

Authentic mayonnaise does not have any kind of pasteurization process nor are there any added preservatives.  Therefore, the eggs will be the first to go 'off' if left on the counter. 

What Happens If You Eat Mayonnaise Left Out Overnight?

In the majority of cases eating bad mayonnaise will not cause any harm. 

However, it could cause the unpleasant side effects of salmonella or food poisoning. Both are unpleasant experiences, so try not to put yourself in danger if you suspect your mayonnaise isn’t good.

How To Tell If Mayonnaise Has Gone Bad

The best thing to do is to be aware of signs that mayonnaise could be bad. Remember this: the FDA has said it can take your body 8 hours to react to mayonnaise left out overnight.

There are indicators to determine whether the mayonnaise could have become stale. Here are some of them:

  • Examine for scents. If the mayonnaise is sour, sulfuric, or sharp, it indicates that it’s been spoiled, and you should not eat it.
  • Are you seeing some odd colors like yellow, white, or perhaps a hint of brown? These are typically indicators that your mayonnaise may be becoming stale.
  • If you find anything that resembles the mold or spores of mold, your mayonnaise should be thrown away.
  • You can try a tiny portion of mayonnaise. You must take it off and throw it out if it’s off in taste. Don’t eat it again.

A few experts suggest that if you see an abundance of separation in your mayonnaise mix, this could indicate it is time to throw it out.

Some separation is normal since the oil will get settled. Mix it all up and test the smell and appearance after stirring it for a while in this instance.

Frequently Asked Questions

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Norah Clark

Norah Clark, Editor of Boyd Hampers! Norah is a food writer with over a decade of experience in hospitality as a pastry chef, sous chef, and barista; former chef at the Savoy Hotel, Ritz Carlton, Four Seasons and Plaza Hotel.

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