Can you Leave a Metal Spoon in Mayonnaise? What Experts Say

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Ever questioned whether it was okay to leave a metal spoon in mayonnaise? As a home cook and food blogger, I frequently find myself questioning this action, since a lot of people are accustomed to doing this, due to several beliefs and cooking myths.

I’ll be delving into the matter in this blog post to examine any studies or research that have been done on it, as well as any potential risks.

Can you leave a metal spoon in mayonnaise?

Many of us have heard the warnings about leaving a metal spoon in food items like mayonnaise, which might give rise to questions about safety and freshness.

So, first things first, let’s talk about the composition of mayonnaise.

Mayo is an emulsion of oil, egg yolk, and either vinegar or lemon juice, with optional seasonings. The high oil content gives it a relatively stable structure, while the acidic components contribute to its preservation.

Now, what about the metal spoon?

The concern that people usually have is about metallic taste or potential reactions with the mayo.

While it’s true that certain foods, especially acidic ones, can react with some metals like aluminum, the metals used in cutlery, such as stainless steel, are generally non-reactive.

This means that leaving a stainless-steel spoon in your mayo is unlikely to cause any unwanted taste or safety concerns.

However, there is an aspect of food safety that’s also note-worthy.

Once you’ve used that spoon to spread mayo on your sandwich, and then dipped it back into the jar, you’ve potentially introduced bacteria into the mayo.

This can increase the rate at which the mayo spoils. So, it’s not the metal spoon per se that’s the problem, but the cross-contamination it could introduce.

How long can Mayonaise be left out before being Unsafe?

Now, despite popular belief, commercially prepared mayonnaise is actually rather acidic thanks to vinegar or lemon juice, which makes it less susceptible to spoilage than one might expect.

But what happens when it’s left outside the refrigerator?

The U.S. Food and Drug Administration (FDA) provides clear guidelines on this: perishable food should not be left out at room temperature for more than two hours.

In environments where the temperature is above 90°F, like a hot summer day, that window decreases to just one hour. These guidelines also apply to dishes made with mayonnaise.

The reasoning behind this is that harmful bacteria, which can cause foodborne illness, love to multiply at temperatures between 40°F and 140°F, also known as the ‘danger zone’.

Leaving mayo or mayo-based dishes out in this range for longer than recommended can lead to bacterial growth, making the food unsafe to eat.

Tips to Make Sure Your Mayonaise is Safe

1. Keep your mayonnaise refrigerated.

    Mayo, like other perishable foods, should be stored at or below 40°F. Sticking to this simple rule will help your mayonnaise last until the “best by” date, and even a bit beyond.

    2. Keep it Clean

    Second, cleanliness is key. As we mentioned before, the biggest threat to your mayo’s longevity isn’t the mayo itself, but rather the possibility of contamination from other foods.

    Always use a clean utensil when scooping out your mayo. If you’re making sandwiches for a crowd, consider spooning out the amount you’ll need into a separate bowl instead of going back and forth to the jar.

    3. Make Sure it’s well closed

    Remember the old saying, “keep a tight lid on it”? It definitely applies here. Always make sure the mayonnaise jar is tightly sealed before you put it back in the fridge. This prevents air and moisture from entering the jar, both of which can expedite spoilage.


    To summarize, it’s not the metal spoon in the mayo that’s a problem but what could be on the spoon from other sources. Cleanliness is paramount when handling foods like mayonnaise to prevent bacterial contamination.

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