How to tell if mayo is bad? (+5 tips)

In this brief article we will address the question, “how to tell if mayo is bad?” as well as the health risks of eating spoiled mayo, how long does mayo take to go bad and how to store mayo. 

How to tell if mayo is bad?

You can tell if Mayo has gone bad by noticing the signs of spoilage mentioned below:

  • A Bad putrid or sour acidic smell 
  • Visible bacterial growth inside the packing 
  • Change is color and taste 
  • Separation of water or oil content

Mayo is a highly acidic food product that does not easily go bad. Having said that, they CAN go bad if proper storage conditions are not maintained or if you leave them out in the open for too long.

Important: You should not consumed spoiled mayo as this can cause different foodborne illnesses as a consequence of the presence of harmful microorganisms (1-3)

There are various indicators that will help you identify if your mayo has gone bad. The signs of spoilage that you should look for. Here are the five tips to tell if your mayo has gone bad:

  1. Texture: Even though mayonnaise lasts for a good amount of time, you should always look for any loss of texture. This is typically in the form of unevenly spread layers in the jar. 

The liquid starts to accumulate and forms another layer on top which can be clearly distinguished when you scoop it out with a spoon and the liquid collects in the hole that the spoon made. 

This is an immediate sign that your mayo has gone bad and it is now time to throw it away. The liquid has an oily appearance that usually can be seen when the mayo is old. The color of mayo also changes.

  1. Color: Fresh mayo has a creamy white color. If you notice a change in colouration then it indicates that your mayo has gone bad. The color of spoiled mayo is usually pale or yellow.

The discolouration occurs as a result of leaving your mayo out in the open for too long. It is a result of oxidation by the atmospheric oxygen. This color usually appears when you leave the jar opened.

  1. Smell: Fresh mayo has a somewhat sour taste that does not irritate the nose. However, if you notice that the smell is putrid or acidic, it means that your mayo has gone bad. 

You should throw the jar in the trash if you notice any off-odor.

  1. Taste: Well, taste is like your litmus test when it comes to any food product. If you notice a bad or unpleasant taste, it is best to discard your mayo. It simply means that the mayo is either oxidized or contaminated.
  1. Mold growth: Since mayo does indeed have a good moisture content – it is basically a thick liquid, there are greater chances of mold growth. Mold growth can usually be seen at the neck of the jar and is a definite sign that you need to throw that jar in the bin.

Changing the jar will not help in any way because the contents of your jar have already been contaminated with the mold.The mold will continue to grow even if you change the jar. 

Be careful as consuming mayo contaminated with mycotoxins produced by molds can lead to severe food poisoning and health issues (4).

Mold or its spores are usually coloured and can be clearly distinguished from the rest of the contents of the jar. You should always check your mayo!

Can you get sick from eating spoiled mayo?

Yes, eating spoiled mayo can pose several health risks due to the potential presence of harmful pathogens and their toxins (1-3). Here are some possible symptoms that someone may experience after consuming spoiled mayo:

  • Gastrointestinal Distress: Consuming spoiled mayo can lead to various gastrointestinal symptoms, such as nausea, vomiting, diarrhea, and abdominal cramps (5). 

Pathogens that may cause these symptoms include SalmonellaStaphylococcus aureus and certain strains of E. coli, such as E. coli O157:H7 (1-2).

  • Food Poisoning: Consumption of spoiled mayo can result in food poisoning, leading to various symptoms such as ever, muscle aches, nausea, and, in severe cases, meningitis, bloodstream infection,blurred vision, difficulty swallowing, muscle weakness, and paralysis (5).

Food poisoning can be a consequence of contamination with Clostridium botulinum (botulism) or Listeria monocytogenes (listeriosis) (6-7).

  • Allergic Reactions: Some people may have specific allergies to ingredients present in mayo, such as eggs or soybean oil. Consuming spoiled mayo can exacerbate these allergies and result in symptoms like hives, itching, swelling, difficulty breathing, or anaphylaxis in severe cases (8).

It is important to note that if you suspect that you have consumed spoiled mayo and are experiencing severe or prolonged symptoms, it is crucial to seek medical attention immediately. Remember that your safety comes first!

How long does mayo take to go bad?

Industrial mayo contains preservatives that help to prolong the shelf life of the product (9). It can last for months when it is stored away from sunlight in a cool and dry place. An unopened jar or pouch of mayo can last up to a year.

In terms of the “best by” date, mayo can last 2-3 months past this date when they are unopened. 

However, once opened, mayo should be stored in the refrigerator. This will keep the product fresh till its expiry date mentioned on the jar or the container.

Since homemade mayo do not contain any preservatives, they last for only a week in the refrigerator. 

How to properly store mayo?

Refrigerating mayo is a good idea to keep the product in its optimal quality. However, you can also store them at the back of a kitchen cabinet in a cool and dry place. Just keep them away from direct sunlight and sources of heat. 

Generally, it is recommended to store opened mayo in the refrigerator and unopened in a cool and dry place.


In this brief article we addressed the question, “how to tell if mayo is bad?” as well as the health risks of eating spoiled mayo, how long does mayo take to go bad and how to store mayo. 


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