Is It Safe to Eat Brown Avocado? Experts Weigh In

Few things can ruin your morning routine more than preparing your avocado toast only to find that the half you saved the day before has turned brown, either in spots or all over. While it's a shock at first, browning on your avocado is normal and is only risky to eat in certain cases. Before you toss out your avocado and settle for your second-choice breakfast, there are a few things you should know to determine if the avocado is truly no longer safe to eat.

We spoke to food science and safety experts to learn why this tasty fruit turns brown, if it's safe to eat, and when it's time to toss it, along with some tips and tricks for keeping cut avocado fresh longer so you can enjoy it.

Why Do Avocados Turn Brown After They're Cut?

Avocados contain an enzyme called polyphenol oxidase. When you slice an avocado in half, you expose the enzyme to oxygen, which triggers a natural reaction called enzymatic browning, according to Jessica Gavin, a certified food scientist and culinary scientist.

"The enzyme speeds up a reaction that converts those compounds into new molecules and forms a brown pigment called melanin. That’s why the bright green flesh slowly turns brown after it’s cut or mashed," Gavin explains. This process also occurs in other produce, such as apples, bananas, and potatoes.

Are Brown Avocados Safe to Eat?

When you open a freshly cut avocado, it is normal to see brown spots or streaks in the flesh. Exposure to oxygen and sometimes minor bruising cause the green color to turn brown, Gavin says. Oxidation affects the avocado's appearance more than its safety to eat.

While a brown avocado is safe to eat, browning can create a subtle bitter flavor that you may or may not enjoy on your morning toast. However, do not eat avocados with black flesh, a slimy or mushy texture, or an off odor. Throw them away instead.

Luckily, avocados that brown from oxidation do not completely lose their nutritional value. "The good news is that most of the avocado’s key nutrients, like heart-healthy monounsaturated fats, fiber, potassium, and vitamins E, K, and B6, remain largely intact during the early stages of browning," Gavin says. "During this reaction, some antioxidant polyphenols break down and form the brown pigment called melanin. As a result, a small amount of antioxidant activity is lost."

When to Throw Away Brown Avocados?

There are several key differences between harmless browning and actual spoilage to look for when assessing your avocado.

To determine whether an avocado is safe to keep or best to toss, start with the color. Harmless browning appears light to medium brown, according to Hermineh Galstian, food safety and quality expert and founder of The Food QA. Spoiled avocados appear very dark brown, gray, or black. "Try scraping some of the brown flesh off - if the flesh underneath is green, then you likely have harmless browning," she suggests.

After scraping, check the texture. The flesh should be creamy and slightly firm, like a normal avocado. If it feels slimy, stringy, mushy, or watery, it's likely spoiled. In addition to texture, smell the avocado. It should have a typical, slightly nutty scent, Galstian says. "Sour, rancid, or other off odors can indicate spoilage," she adds. "If you decide to taste it, harmless browning can make the flavor slightly bitter. However, if there are strong off or sour flavors, this is a sign of spoilage."

If you notice any of these signs, discard the avocado immediately.

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How to Slow Avocados From Browning

If you've cut your avocado and don't need to use the other half right away, use these tips to slow the browning process.

First, after cutting, leave the pit in, Galstian advises. The pit reduces the surface area exposed to oxygen, which helps prevent browning underneath it. Next, squeeze lemon or lime juice over the flesh. "The acid in the juices reduces the chemical reactions that take place when the enzyme in the avocado is exposed to oxygen," Galstian says.

Store the avocado cut-side down in a container, or cover it tightly with plastic wrap or foil. Gavin also suggests brushing olive oil on the cut side and placing it cut-side down on a lightly oiled plate to create a barrier between the fruit and the air. Once covered, refrigerate it. The cool temperature slows the chemical reactions that cause browning.