June 6, 2024

How Long Can Mayo Sit Out?

How long can mayo sit out? You should not leave mayonnaise out at room temperature for more than two hours. Mayonnaise usually contains raw eggs, which can begin growing harmful bacteria like salmonella, listeria, and E. coli if left out too long. Eating spoiled mayo can lead to serious illness.

mayonnaise in cup
  • Raw eggs in mayonnaise create a breeding ground for bacteria like salmonella if left unrefrigerated. Keep mayo cold and discard mayo left out for more than 2 hours.
  • Spoiled mayo can cause serious illness. Symptoms of food poisoning from bad mayo include nausea, vomiting, cramps, diarrhea, fever, chills, and headaches.
  • Keep unopened mayo in the fridge until the “Best By” date. Opened mayo lasts 2-3 months for commercial brands, 4 days for homemade. Use clean utensils and avoid double-dipping to prevent contamination.

Discovering you got sick from eating contaminated mayonnaise can be upsetting, especially if it occurred due to mishandling during the manufacturing or retail process. If you have become ill from mayonnaise, contact Keep Food Safe. We can connect you with a lawyer to discuss your options for seeking fair compensation.

Why Should Mayo Be Refrigerated?

Mayonnaise contains raw eggs, which are highly perishable and prone to bacterial contamination. In the U.S., eggs are washed before sale, removing their natural protective coating and making them more susceptible to bacteria entering through the porous shells.

Refrigerating mayonnaise slows the growth of harmful bacteria like salmonella, a leading cause of foodborne illness. Bacteria multiply most rapidly between 40 F and 140 F, known as the “danger zone.” Leaving mayo unrefrigerated for more than two hours significantly increases the risk of these bacteria reaching unsafe levels.

What Happens When Mayo Sits Out Too Long?

When mayonnaise is left at room temperature for an extended period, the raw eggs in the emulsion provide an ideal environment for dangerous bacteria to thrive. After sitting out for more than two hours, the following bacteria can proliferate:

Ingesting mayonnaise contaminated with these bacteria can cause serious foodborne illnesses. Contrary to popular belief, the acid content in mayonnaise from vinegar or lemon juice is insufficient to prevent bacterial growth over extended periods without refrigeration.

In many cases of illness linked to foods like chicken salad, tuna salad, or sandwiches, it’s often the meat, poultry, fish, or eggs that have been kept unrefrigerated for too long that is the source of the bacterial contamination, not the mayonnaise itself.

Side Effects of Eating Spoiled Mayo

Consuming mayonnaise that has gone bad can cause food poisoning with the following symptoms:  

  • Nausea and vomiting: The onset of nausea and vomiting can occur within a few hours of eating contaminated mayo.
  • Abdominal pain and cramps: Painful cramps and discomfort in the abdominal region are common signs of gastrointestinal distress.
  • Diarrhea, sometimes bloody: Watery or loose stools may persist for several days. In severe cases, there may be blood in the stool.
  • Fever and chills: A low-grade fever and chills often accompany foodborne illnesses as the body tries to fight off the infection.
  • Headache: Dehydration and electrolyte imbalances from vomiting and diarrhea can trigger headaches.
  • Muscle aches: General weakness and muscle pain may occur as the immune system responds to harmful bacteria.

Severe salmonella infections, in particular, can lead to life-threatening complications, especially for vulnerable groups such as the following:

  • Young children under 5 years old
  • Older adults over 65
  • Infants who are not breastfed
  • Those with weakened immune systems due to chronic illnesses or medications

These high-risk individuals may experience more intense symptoms and have a higher likelihood of hospitalization due to dangerous dehydration, electrolyte imbalances, and high fever.

In rare cases, a salmonella infection can trigger reactive arthritis, an autoimmune condition causing painful swelling of the joints, eyes, and urinary tract. Symptoms of reactive arthritis may appear several weeks after the initial illness and can last for months or even years, significantly impacting the affected person’s quality of life.

If you believe you have developed a severe foodborne illness or prolonged symptoms after consuming contaminated mayonnaise, seek medical attention promptly. Keep records of your treatment, as you may be entitled to compensation for your physical, emotional, and financial hardships.

How Long Can a Sandwich With Mayo Sit Out?

Sandwiches made with mayonnaise are subject to the same two-hour rule as mayo on its own. Regardless of the type of bread, if the sandwich contains perishable fillings like meat, poultry, fish, eggs, or mayonnaise, it should not sit out for more than two hours—or one hour if the ambient temperature is above 90 F. 

Even if the sandwich still looks and smells fine after a few hours, it could harbor unsafe levels of bacteria that can make you sick. Always refrigerate sandwiches promptly if not consuming them within two hours.

How To Tell if Mayo Has Gone Bad

Spoiled mayonnaise often shows signs that it’s no longer safe to eat, such as:  

  • Color changes: Fresh mayo is a pale ivory or white. If it appears yellow, brown, or greenish, discard it.
  • Off odor: Mayo that smells rancid, sour, or strangely chemical-like should be thrown out.  
  • Sour taste: Give it a taste only if it looks and smells okay. If it’s acidic, bitter, or “off,” spit it out and dispose of the rest.

Other red flags include visible mold, ingredient separation, or a noticeably thicker/thinner texture than usual. However, remember that dangerous bacteria can still be present before noticeable signs of spoilage develop when mayo is left unrefrigerated for too long.

How To Safely Store Mayo

To maximize the shelf life of mayonnaise and prevent bacterial growth, always keep it refrigerated at 40 F or below. Store the container tightly sealed in the fridge at all times when not in use. If you’re unsure about the temperature of your refrigerator, use a thermometer to ensure it’s at or below 40 F.

When shopping for mayonnaise, check the “Best By” date on the package. This date indicates the manufacturer’s estimate of how long the product will remain at peak quality. Unopened store-bought mayo can typically be kept in the refrigerator for up to three or four months after this date, but it’s essential to note that the “Best By” date is not a safety deadline.

Some manufacturers may print a date up to 30 days after packaging, so the “Best By” date alone is not always a reliable indicator of freshness. Instead, use your senses to evaluate the quality of the mayonnaise before consuming it. If you notice any signs of spoilage, such as discoloration, off-odors, or changes in texture, discard the mayonnaise regardless of the printed date.

Once opened, commercial mayonnaise is generally safe to use for two to three months if continuously refrigerated. However, homemade mayonnaise and varieties made with olive oil instead of vegetable oil may spoil faster due to their lack of preservatives and different compositions.

For the best quality and safety, use opened jars of homemade mayo within four days and store-bought olive oil-based versions within two months.

To minimize the risk of contamination, always use clean utensils when scooping mayonnaise from the jar. Avoid double-dipping or introducing any food particles into the container, as this can accelerate spoilage. If you suspect that the mayonnaise has been left out for too long or contaminated with other food items, err on the side of caution and discard it. When in doubt about the safety of your mayonnaise, observe the two-hour rule.

If you suspect foodborne illness from contaminated mayonnaise, eggs, or another food product, contact Keep Food Safe today. Our team can connect you with trusted legal representation to help you explore your options for pursuing compensation. You shouldn’t have to suffer due to a manufacturer’s negligence. Let us help you seek the justice you deserve.

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