How Long Can Mayonnaise Be Left Out of the Fridge?

by Charlie
Published: Last Updated on
Homemade mayonnaise

There are ongoing debates about jars of pickles and preserves, and mayonnaise often falls into the “fridge or cupboard” argument. However, it contains things like egg, and that might lead you to wonder whether it’s safe to leave it at room temperature or not.

How long can mayonnaise be left out of the fridge? Mayonnaise should not be left out of the fridge for more than eight hours at the most. Mayonnaise does have preservatives in it, but it is still supposed to be refrigerated at all times once it has been opened. Unopened mayonnaise can be kept in a cool, dark cupboard and doesn’t need to be refrigerated.

Is Mayonnaise That Has Been Left Out Overnight Safe to Eat?

If you have accidentally left a jar of mayonnaise on the counter overnight, you should not eat it. Mayonnaise should only be left at room temperature for a maximum of eight hours, and an overnight period is likely to exceed this.

If you left it out right before you went to bed and you refrigerate it the moment you get up, it may be safe to eat still, especially if you sleep for less than eight hours. However, you should bear in mind that this will have significantly shortened its shelf life, and you should use it up more quickly even if it stays in the fridge from then on.

The longer mayonnaise stands out for, the more time bacteria has to grow and multiple throughout it, and therefore the greater the chance it could make you sick if you eat it. Be careful with mayonnaise that has been left out for more than a few hours.

If your kitchen is warm, you should reduce the eight hour estimate a bit, as bacteria may spread more quickly.

How Long Will Mayonnaise Last in the Fridge?

If properly stored, mayonnaise should keep for two or three months in the fridge. That’s why it’s so important to refrigerate your mayonnaise properly. Leaving it out will shorten that shelf life, even if you refrigerate it afterward.

If your mayonnaise gets contaminated by other foods, its shelf life may be reduced. Always use a clean spoon or knife to serve mayonnaise to reduce the risk of contaminating it with other products.

How Long Will Mayonnaise Last in a Cool Cupboard?

If you place opened mayonnaise in a cool cupboard, it will still only have a shelf life of around eight hours. Unless the cupboard is lower than 50 degrees F, bacteria will continue to breed in the mayonnaise, and it will soon be unsafe to eat.

A cupboard is not a suitable place to store mayonnaise unless you live in a very cold home and it is reliably below 50 degrees F. Even then, a fridge is still a preferable option for keeping your mayonnaise fresh.

How Do You Tell If Mayonnaise Has Gone Bad?

When you want to eat mayonnaise you are unsure about, take some time to inspect it.

Use your senses and check for:

  • Flecks of blue or white mold on the surface
  • A sour or putrid smell
  • Discoloration (e.g. brown or very dark patches of mayonnaise)
  • A funny taste, especially if it’s sour

You should only resort to the taste test if you can’t tell from the other factors, but usually mayonnaise will show visible signs of having gone off. If you do need to taste it, make sure you only put a small amount in your mouth, and spit it out if it tastes bad.

A small quantity of moldy mayonnaise is unlikely to hurt you, but it’s still better not to consume it. 

What are the Risks of Eating Mayonnaise That Has Gone Bad?

Eating off mayonnaise could lead to food poisoning. Any of its ingredients could go off, but egg yolks are a particular concern for some people. If your mayonnaise has gone off, it might make you very ill.

The effects of food poisoning can range from discomfort and stomach cramps to diarrhea or even hospitalization. Although most people will not end up in hospital as a result of eating bad mayonnaise, it is important to be cautious about compromised food and not take unnecessary risks.

If you think mayonnaise has been stored wrongly or has expired, you should throw it away. It is no longer safe to consume and there is nothing you can do to change this. 

How Long Can Homemade Mayonnaise Be Left Out of the Fridge?

Homemade mayonnaise should never be left out of the fridge. You should always put it straight back in the fridge when you have finished using it, and not allow it to sit on the counter for any length of time.

This is because homemade mayonnaise goes off a lot more quickly than store-bought mayonnaise. Commercial mayonnaise contains a lot of preservatives that keep the food fresh and prevent the spread of bacteria, but homemade mayonnaise does not benefit from these.

One of the biggest differences is that commercial mayonnaise is made using pasteurized eggs. The pasteurization process kills off any salmonella bacteria in the eggs, making them safer for consumption and increasing the lifespan of the mayonnaise.

Homemade mayonnaise tends to be made with unpasteurized egg yolks, and these may be contaminated with salmonella. Because the condiment is not cooked, there is a risk of bacteria remaining in the egg yolks and spreading through the mayonnaise.

You can reduce the speed with which bacteria may spread by refrigerating homemade mayonnaise, but if it gets left at room temperature, it should be discarded rather than eaten, as it is very possible for it to contain salmonella without any visible trace.

Homemade mayonnaise also has a much shorter shelf life. In general, it needs to be used within a week or less of being made.

Final Thoughts

Mayonnaise can be left out of the fridge for up to eight hours, which is unusually long – most foods need to be refrigerated within two hours. However, it is not recommended that you leave it out for this long; it is better to keep it refrigerated.

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