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How Long Does Mayonnaise Last? | Refrigerated vs. Left Out

Wondering how long mayonnaise will last is a common concern. We all know that ketchup can be left out for extended periods without having to worry about it going bad. But what about mayo? I did some extensive research and can give you a definitive answer.

Mayonnaise can last over a year in an unopened container before it starts to degrade nutritionally. Once opened, mayo can last 2 to 3 months if refrigerated but just a few hours when left out. This is because one of the ingredients, egg yolks, spoils quickly once exposed to air and warm temperatures.

Mayonnaise is a staple in most US homes. While some may consume the nation’s favorite creamy condiment quickly, others may have a jar lingering at the back of the fridge and be curious to know if it is still viable. There are several telltale signs that food has started to expire, and it’s good to be on the lookout for them.

Mayonnaise in a Small Bowl with a Spoon

How To Tell If Mayonnaise Has Gone Bad

Identifying if a product has expired prior to consuming it can save you from suffering adverse health effects. There are several simple ways to inspect your mayonnaise for signs that it has expired.

Before anything else, look for evidence of mold or any other foreign growths inside the jar. If you detect this, discard the mayonnaise immediately. While taking in the visual appearance of the mayonnaise, appreciate the color of the condiment. If it appears to be a darker shade, then that indicates that the egg content has started to deteriorate. Throw the mayonnaise away to avoid any adverse health effects.

You can also use your sense of smell and taste to determine if the mayonnaise has gone bad. Any foul smell or altered taste that is repulsive is a clear sign that bacteria have started to propagate.

A final indicator is the texture of the product. Mayonnaise is an emulsion, which is when two immiscible liquids, like oil and water, have been forced to combine. Therefore, mayonnaise should be a homogenous spread, void of lumps. If you find lumps in your mayonnaise, it’s a sign that the ingredients have separated, and the product is no longer in its intended condition for human consumption. Best to be safe than sorry and throw any suspect mayonnaise away.

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It isn’t always possible to detect whether your mayonnaise has expired. All of the above conditions are tailored to inspecting the jar when using it after a while of neglect. However, most illnesses associated with food poisoning from mayonnaise emanate from eating foods that were prepared with mayonnaise and then left at room temperature, or warmer. Potato or macaroni salads at buffets or picnics are prone to expiring. The mayonnaise is exposed to the air and is held at temperatures that are prime for bacteria to grow. You even have to be careful with thousand island dressing.

If you don’t know how long such an item has been sitting out, avoid it. At the end of a picnic, throw these items away, don’t risk keeping the leftovers for later. Spoiled mayonnaise should be avoided as you will likely contract a foodborne illness, primarily from the bacteria salmonella.

What Prolongs the Life of Mayonnaise?

The shelf life of mayonnaise depends on how it was made, whether the container has been opened, and the temperature at which the condiment was stored. A mass-produced jar or bottle of mayonnaise uses clean manufacturing systems that preserve the product for up to a year. That’s why most purchased mayonnaise products have best by dates well into the future.

Granted, a best by date is not the same as an expiration date. Best by date refers to the age at which the manufacturer guarantees that the nutritional content of the product is the same as it was at the time of manufacturing, if unopened. In contrast, an expiration date is when a product starts to degrade and become unsafe for human consumption. For this reason, most condiments are sold with best by dates that are at least a year into the future. However, it will still be fit for consumption far past that date; it just will have lost some of its nutritional value.

An unopened, mass-manufactured jar, bottle, or packet of mayonnaise will last for years, at room temperature. This is possible because the product is kept airtight, eliminating oxygen from the product. As a result, any bacteria or fungi that survived the manufacturing process are not able to replicate. Once mayonnaise comes into contact with the air, the product starts to oxidize and becomes an optimal environment for bacteria to multiply.

Typically, a mass-manufactured mayonnaise product will last 2-3 months after opening if it stored in a refrigerator. Once opened, at room temperature, it will only last a few hours, so make sure you get it in the fridge quickly after use. The expiration time cannot be precise, as the degradation rate depends on how you use your mayonnaise. The shorter the period your mayonnaise is out of the refrigerator, the longer it will last. Further, if you reseal your mayonnaise quickly, it too will prolong its shelf-life. Remember, bacteria can replicate in as little as twenty minutes. Use your mayonnaise speedily and keep it cool for the best longevity.

Related What Condiments Do Not Need to Be Refrigerated After Opening?.

Reducing exposure to air prompted several condiment makers to offer their products in squeezable bottles. By doing so, the air entering the container is minimalized. If you are an irregular user of mayonnaise, buying a squeezable version will help prevent waste.

Homemade mayonnaise is exposed to air throughout its manufacturing process. Therefore, it doesn’t last as long as mass-produced mayonnaise that’s made in clean environments. Typically, homemade mayonnaise will last around a week in the fridge before it starts to turn.

Why Expired Mayonnaise Can Make You Sick

Consuming most expired food products will lead to adverse health effects. Mayonnaise is no different. The egg yolks in mayonnaise are a prime breeding ground for the bacteria salmonella, which, when ingested, causes the infection, salmonellosis that affects the intestinal tract.

Sometimes, this infection does not lead to noticeable symptoms. However, it can make you rather sick for two to seven days. Expect abdominal cramps, fever, vomiting, nausea, headaches, chills, and diarrhea as side effects of your body fighting the infection. It is possible for your condition to become life-threatening if you are in a high-risk health group. The main pathway for such danger is dehydration from excessive vomiting and diarrhea.

Even after the symptoms subside, the infection can persist inside your bowels for several months before it is fully cleared from your system.

Final Thoughts

Mayonnaise has come a long way since its invention in France during the 18th century. It is consumed worldwide, each with a slight adaptation to suit local culinary culture. Presently, mayonnaise is America’s highest-selling condiment, raking in sales in excess of $2 billion each year. It has a multitude of uses, including being applied as a sandwich spread, as the base for number salads, or as a creamy dip for French fries

Unopened mass-manufactured jars, bottles, or packets of mayonnaise will last for years before it becomes unfit for consumption. Once opened, keep the mayonnaise covered in a refrigerator for up to three months. Following this, check for signs that your mayonnaise has started to become a breeding ground for bacteria before eating. Any mayonnaise that has been at room temperature for a prolonged period should be avoided as it is likely to be overrun with the bacteria salmonella, which will cause food poisoning if ingested.

Related Questions

How Do You Make Mayonnaise?

Various recipes exist for mayonnaise, with each brand and chef having their own twist on this classic condiment. However, at its core, mayonnaise is made from oil, raw egg yolk, lemon juice, and seasonings. When making homemade mayonnaise, you will want to add a touch of mustard as it not only adds flavor, it also helps keep the mixture together.

Using a food processor, add the egg yolks first and beat, then your seasonings and mustard. Once that is mixed, very slowly add the oil. Mayonnaise is an emulsion, which means it’s a mix of liquids that do not blend. Adding the oil too fast will not let the droplets of oil disperse properly, and your mayonnaise will split. Once made, keep your mayonnaise covered and refrigerated until use.

Is There a Vegan Version Of Mayonnaise?

Yes, you can make vegan mayonnaise. Several recipes exist, some of which are best made fresh. Ultimately, the variations are down to what substitute has been used to replace the egg. Aquafaba (Amazon Link), made from chickpea juice, is a popular choice, as is tofu. If You don’t mind nuts, cashews can also be used. Many recipes will also include nutritional yeast to provide a “dairy” consistency to the mayonnaise. Finally, in Spain, mayonnaise is made with milk rather than eggs, so a typical vegan mayonnaise uses soymilk as the base.

Can Mayonnaise Be Used For Beauty Treatments?

Mayonnaise isn’t just ubiquitous in the kitchen. It can also be considered universal in the beauty department too. The oils in mayonnaise make it an excellent conditioner for your hair and dry skin. For the same reason, it is an excellent alternative to after sun lotion. Lather some mayonnaise onto the affected area, and you will feel relief while the skin is conditioned simultaneously. The condiment does more than just moisturize, though. Dipping your fingernails in mayonnaise will strengthen them, and rubbing it on your face will provide a quick facial. So, if you’re ever stuck, reaching for the jar of mayo in your fridge just might be the answer.