Hi there! Chef Michael here, ready to break down some common food myths and give you the facts you need to keep your kitchen safe and delicious. Today, we're tackling a question that's been the source of many a picnic-basket debate: Do you REALLY need to refrigerate mayonnaise?

The short answer? It depends. Let's unpack that, shall we?

Commercial Mayonnaise: Playing it Safe

Commercially prepared mayonnaise, the kind you find in jars on supermarket shelves, typically boasts a high acidity level. This is due to the presence of ingredients like vinegar and lemon juice, which act as natural preservatives. This acidity, combined with pasteurization (a heating process that kills harmful bacteria), makes commercial mayonnaise relatively shelf-stable.

However, while unopened commercial mayonnaise can generally sit at room temperature for a while, once opened, refrigeration is key. Exposure to air introduces bacteria, and while the acidic environment might slow their growth, it won't eliminate the risk entirely. Refrigeration helps maintain the quality and safety of your mayonnaise, preventing spoilage and potential foodborne illnesses.

Homemade Mayonnaise: A Different Story

Now, let's talk homemade mayonnaise. While the creamy goodness of freshly made mayo is undeniable, it also comes with a higher risk factor. Why? Because homemade mayonnaise typically uses raw eggs.

Raw eggs have the potential to carry *Salmonella*, a bacteria that can cause food poisoning. While the vinegar or lemon juice in your recipe does offer some level of protection, it's not a foolproof safeguard. Therefore, **refrigeration is non-negotiable for homemade mayonnaise**. Always store it in an airtight container in the refrigerator and consume it within a few days.

Signs Your Mayonnaise Has Gone Bad

Whether store-bought or homemade, it's essential to be able to recognize when mayonnaise has passed its prime. Here are some telltale signs:

* Off smell: Fresh mayonnaise has a clean, slightly tangy aroma. A rancid, sour, or unpleasant odor is a sure sign of spoilage.
* Discoloration: Mayonnaise should be a pale yellow or creamy white. If you notice any significant yellowing or browning, it's time to toss it out.
* Separation: Mayonnaise is an emulsion, meaning it's a mixture of oil and water held together by egg yolks. If you see the mixture separating or a layer of oil forming on top, it's a sign the emulsion has broken and the mayonnaise is no longer safe to eat.
* Changes in texture: Fresh mayonnaise is smooth and creamy. If you notice any curdling, lumpiness, or a watery consistency, it's best to err on the side of caution and discard it.

**The Bottom Line: Don't Gamble with Food Safety**

When it comes to mayonnaise, it's always better to be safe than sorry. Refrigeration is a simple yet crucial step in preventing foodborne illness and ensuring your culinary creations are both delicious and safe to enjoy.

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Leaving mayonnaise out at room temperature is acceptable as long as it's not contaminated by other food or dirty utensils, but keeping it in the fridge helps extend its shelf life. Commercially produced mayonnaise, as opposed to the homemade version, does not need to be refrigerated, according to the report.read more >>