Hi there! Chef Ken here, at your service. With decades of experience in the culinary arts, from bustling restaurant kitchens to quiet home kitchens, I've dealt with every ingredient under the sun, mayonnaise included. It's a staple, no doubt, but knowing how to store it and tell if it's still good is key to a safe and delicious meal. Let's dive into your question about unopened mayonnaise and those all-important expiration dates.

Let's get one thing straight off the bat: **expiration dates on mayonnaise jars are not a hard and fast rule.** Think of them more like guidelines. These dates, typically "best by" or "use by" dates, are set by manufacturers to indicate when the mayonnaise will be at its peak quality in terms of flavor and texture.

**So, how long *can* unopened mayonnaise last past this date?**

Here's the deal: unopened mayonnaise, if stored properly in the refrigerator, can often stay fresh for several weeks or even months past the printed date.

Why so long?

Mayonnaise is naturally acidic, thanks to the vinegar or lemon juice in it. This acidity creates an environment that's hostile to many types of bacteria that cause spoilage.

**But don't just take my word for it. Here's what to look out for:**

* Storage is Key: The refrigerator is your mayonnaise's best friend. Keep it consistently cold at 40°F (4°C) or below. Never leave it out at room temperature for more than two hours, especially after it's been opened.
* Check that Seal: A good seal on the jar is essential for keeping that freshness locked in. Make sure the lid is tightly closed and there are no signs of damage or bulging.
* Engage Your Senses: Even with proper storage, mayonnaise can eventually go bad. Before using, give it a good look-over.
* Appearance: Has the color changed? Is there any separation or curdling? These could be signs of spoilage.
* Smell: Trust your nose! Does it smell off, rancid, or just not quite right? If so, it's time to toss it.
* Texture: The texture should be smooth and creamy. If you notice any grittiness or mold (a big no-no!), it's a goner.

Remember, when in doubt, throw it out! It's always better to err on the side of caution when it comes to food safety.

Let me know if you have any other questions! Happy cooking!
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Mayonnaise is still good for a month after its expiration date (unopened) and up to four months after opening. Eggs, properly refrigerated, should last at least three to five weeks after the "sell-by" date. Canned goods are good to eat long after labeling dates, as long as the can is in good shape.read more >>