Hi there! I'm Chef Emily, and I've been a professional chef for over 15 years. I'm also a certified food safety instructor, so I can tell you everything you need to know about keeping your food safe to eat.

Leaving mayonnaise out overnight is a big no-no in the food safety world. Here's why:

Mayonnaise and Bacterial Growth

Mayonnaise is made from oil, eggs, and an acidic ingredient like lemon juice or vinegar. While the acidic component provides some level of protection, mayonnaise is still considered a high-risk food when it comes to bacterial growth. This is mainly because of the eggs.

* Eggs and Salmonella: Raw eggs can sometimes contain a type of bacteria called Salmonella. Salmonella can cause food poisoning, leading to symptoms like fever, diarrhea, and abdominal cramps. While commercial mayonnaise uses pasteurized eggs, which significantly reduces the risk of Salmonella, there's still a chance, especially if the mayonnaise isn't stored properly.

* Temperature Danger Zone: Bacteria thrive in what we call the "temperature danger zone," which is between 40°F (4°C) and 140°F (60°C). Leaving mayonnaise out at room temperature overnight puts it squarely in this danger zone, giving bacteria ample opportunity to multiply.

The 2-Hour Rule

The general rule of thumb for perishable foods like mayonnaise is the "2-hour rule". This rule states that you should never leave perishable foods out of refrigeration for more than 2 hours. This time limit is cut down to just 1 hour if the ambient temperature is above 90°F (32°C).

Leaving mayonnaise out overnight far exceeds this recommended time frame. Even if the mayonnaise looks, smells, and tastes fine, it could still harbor dangerous bacteria that are invisible to the naked eye.

**Consequences of Consuming Spoiled Mayonnaise**

Consuming mayonnaise that's been left out overnight can lead to food poisoning. Symptoms of food poisoning can range from mild to severe and typically include:

* Nausea
* Vomiting
* Diarrhea
* Abdominal cramps
* Fever
* Headache
* Weakness

In some cases, food poisoning can lead to serious complications, especially in individuals with weakened immune systems, young children, pregnant women, and the elderly.

Playing it Safe

When it comes to food safety, it's always best to err on the side of caution.

* Refrigerate promptly: Always store mayonnaise in the refrigerator at or below 40°F (4°C).
* Check the expiration date: Pay attention to the "use by" or "best by" date on the mayonnaise jar.
* Don't risk it: If you're unsure whether mayonnaise has been left out for too long, it's best to throw it away.

Remember, preventing foodborne illness is always better than treating it. Following these simple guidelines can help ensure that you and your loved ones stay safe and healthy.

read more >>

Answer: You can let an opened jar of mayonnaise sit out at room temperature for up to 8 hours, says the United States Department of Agriculture. Opened mayonnaise that has been held above 50 degrees Fahrenheit for more than 8 hours should be discarded.read more >>