While you may love avocados year-round, imports of this creamy green fruit increase by as much as 40 percent in January and early February, according to an industry report, likely because of all that delicious guacamole on game day. There’s nothing wrong with consuming avocado, which contains fiber and potassium and is a plant-based source of healthy fats, according to the United States Department of Agriculture (USDA), but when it comes to the proper way to store sliced avocado, it’s things are known to get a little risky.
Sliced avocados tend to brown easily, and while there are many hacks that claim to prevent that process and keep avocados fresh for a month, not all of them are safe. Following the wrong advice can even lead to foodborne illness. In 2022, the U.S. Food and Drug Administration (FDA) issued a warning in response to a viral trend on social media that suggested storing whole or cut avocados in water keeps them fresh longer. The videos continue to generate more and more views.
In one, which received more than four and a half million views, TikTok user @sidneyraz kept half an avocado in a container of water and took it out the next day to find it was still ripe and green. Another user, @shamamamahealing, stored an uncut avocado in a jar of water in the refrigerator, which revealed perfectly smooth, green fruit inside after two weeks of soaking. Her video quickly went viral and was viewed more than six million times before she deleted it. Newsweek reported.
The idea sounds plausible. Avocados begin to brown when exposed to oxygen, in a process called oxidation, says Matt Regusci, the chief compliance officer at New Era Partners, a company that specializes in food safety compliance. “The same thing happens with apples and potatoes,” he explains. “There’s nothing wrong with the tan in terms of health risk, it just doesn’t look good.”
Storing avocados in water, users suggest, will slow the oxidation process and keep the fruit ripe and green for longer. But according to the FDA, this practice can have serious health consequences. As @sidneyraz exclaimed in a later video retracting his advice (which was viewed just under 750,000 times): “Take the avocados out of the water!”
What are the health risks of storing sliced avocados in water?
While water can preserve the freshness and flavor of an avocado for a while, it can also expose you to foodborne illness. “The biggest concern is the possibility that any remaining human pathogens (such as Listeria monocytogenes and salmonella) that may be on the surface of the avocado can multiply during storage if submerged in water,” notes Janell Goodwin, a spokesperson for the FDA.
Previous FDA research found that 17 percent of imported and domestic avocados showed traces of Listeria monocytogenes on their skin, and 1 percent tested positive for salmonella. According to the USDA it is Listeria monocytogenes can cause fever, muscle aches, nausea and diarrhea; salmonella can cause fever, diarrhea and abdominal cramps. Both can cause serious illness and death in people with weakened immune systems Listeria monocytogenes can be especially dangerous for pregnant women, newborns, and older adults.
“Bacteria such as listeria and salmonella are living things. They need the right temperature, food and especially water to grow,” says Regusci. “If you cut an avocado into pieces, divide it in half and then immerse it in water, you create the perfect environment to create a disease-causing soup.”
If you choose not to cut your avocados before submerging them, you may still be at risk. Even whole, washed avocados can contain spores of bacteria that, over time, make their way into the edible part of the fruit.
“[Past] research conducted by FDA scientists has shown that Listeria monocytogenes has the potential to infiltrate and settle into the pulp of avocados within 15 days of refrigerated storage when immersed in refrigerated dump tanks,” says Goodwin. “In this case, even disinfecting the avocado skin before cutting does not remove the contamination.”
How can you safely keep avocados fresh?
Avocados should be stored on the counter as soon as you buy them; Once they’re ripe, you can put them in the refrigerator to extend their life by a day or two, according to the Cleveland Clinic. The FDA recommends rinsing whole avocados under running water and scrubbing them with a firm brush to remove any dirt or bacteria, then drying them with a clean towel and storing them at room temperature until ripe.
Once you’ve cut open the avocado, add a squeeze of lemon or lime juice to the exposed surface if you don’t plan to use the whole fruit right away. This will help keep them fresh longer, as the citric acid in these fruits can slow the oxidation process, says Regusci. Then wrap the fruit in plastic wrap until you are ready to eat it.
Storing avocado in the freezer is another way to prevent bacterial growth (a video about freezing avocados on TikTok, posted by @livecomposed, has been viewed nearly 11 million times), Yahoo reported. Freezing food to 0 degrees Fahrenheit will inactivate any bacteria present in food, notes the USDA (but keep in mind that these bacteria can continue to multiply as usual once the food is thawed). Although the video shows whole frozen avocados, cutting them before freezing can be helpful and a way to maintain portion control.
“Divide the avocados into quarters, peel off the skin and throw them in a container [resealable plastic] bag. Add a little lemon or lime juice and put it in the freezer,” Regusci advises. (Keep in mind that ice crystals can slightly change the texture of your avocados, so this hack is best for avocados you want to use in smoothies, mousses, or other blender recipes.)
Citrus juice can also keep your bowl of guacamole from turning brown by preventing oxidation, according to a previous study that found onions have a similar effect. If you have any leftover guacamole, sprinkle some lime juice over it and place plastic wrap directly on the guacamole (instead of stretching it tightly over the top of the bowl). “You want as little product as possible exposed to the air,” says Regusci.
You can also store guac in gallon-sized bags in the freezer. “Pushing the guacamole flat in the bag exposes the product to the least amount of air and allows it to lay nice and flat in the freezer for better storage,” says Regusci.
The takeaway
While there are a number of creative ways to enjoy avocados, the struggle to keep them from turning brown is real. While it is not unsafe to eat a brown avocado or guacamole that has darkened after exposure to the air, it is far from appealing. Storing avocados in water is not a good idea because it increases the risk of pathogens such as listeria and salmonella, which can cause foodborne illness. Fortunately, you now know several safe, expert-approved options for preserving avocados for maximum enjoyment.