It happens to all of us: the lettuce we picked up at the farmer’s market was perfect when we got it home, but two days later it mysteriously has brown spots. That beautiful bunch of bananas we brought home from the grocery store had a massive freckle attack after a few days. All the fruits and vegetables we buy are subject to oxidation and decay, but is it always a cause for alarm? When is it okay to eat brown produce, when should we toss it, and how can we slow down the breakdown process?
Aside from the financial cost of wasting food, there are other reasons not to throw out produce because it's a little brown. While hundreds of millions of people go hungry every day around the world, Americans alone waste an estimated 70 billion pounds of food every year. Approximately 25 to 40 percent of food grown, processed, and transported in the US is never eaten, and food that ends up in landfills contributes a significant amount to levels of a dangerous greenhouse gas called methane.
At the same time, we don’t want to give our family or ourselves brown or bruised fruits and vegetables that can jeopardize our health. Sure, we can put damaged produce into our compost pile, and that’s at least an environmentally sound solution when the fruits and vegetables aren’t safe to consume. But typically a modest amount of browning is not a reason to toss away the food. According to the Michigan State University Extension, “bruising does not indicate the produce is past its prime.”
Browning and bruising of produce
Fruits and veggies are susceptible to bruising from the moment they are picked or plucked, processed, packed, and placed in markets, where consumers then have an opportunity to pick them up, poke them, and put them back for more handling.
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Along with ample opportunity for produce to be bruised, there’s the browning factor. Fruits emit a gas called ethylene that speeds up the ripening process and causes them to brown faster. Some of the fruits that give off the most ethylene include apples, cantaloupe, peaches, pears, and tomatoes. Keep these high-gas emitters away from other fruits and even vegetables.
Brown areas on lettuce may look unappealing but they rarely are associated with any health risks and don’t indicate any nutritional loss, according to University of California Berkeley. Browning lettuce can be caused by oxidation (exposure of bruised or cut leaves to air); tip burn, which is associated with soil or climate conditions; or exposure to high-gas emitters, so keep your apples away from your greens. Lettuce that has a pink tinge in the middle rib has likely been exposed to high temperatures, but the lettuce is perfectly safe to eat.
Once you cut fruit, it begins to turn brown because of exposure to oxygen and enzymatic reactions within the tissues. To slow this process, sprinkle the cut portion of the fruit with lemon juice. Another option is to place the cut fruit in ice cold water. This is especially effective for avocados, which oxidize quickly. A cut avocado in ice water will stay green for up to four hours.
When to throw it out
Should we automatically throw away a bruised piece of fruit or a vegetable that has some tissue breakdown? What if we can see or smell fungus? What if there's mold around the stem? The answer depends on whether the fungi or mold has penetrated the food. If you have a mildly moldy apple, bell pepper, or carrot, then it’s usually safe to simply cut away the affected portion, since mold has a difficult time compromising produce with firm exteriors. However, softer fruit like a moldy banana should be thrown away.
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Here are a few other important things to know:
Soft rot. Vegetables are susceptible to soft rot, which occurs when bacteria infiltrate the tissues. It is safe to eat these foods once you cut away the affected areas. The bacteria that cause this rot are not associated with food poisoning.
Wilting and wrinkling. Both wilting and wrinkling of produce are indications of moisture loss and are not a health risk. It’s easy to “revive” wilted broccoli, lettuce, and other greens, or wrinkled bell peppers and tomatoes by putting them in ice water for about 5 minutes or by cooking.
Brown avocados. Both bruised and cut avocados turn brown, inside and outside. If the avocado is slightly browned (a brown mark here or there), it is still safe to eat. However, avoid eating avocado flesh that has turned dark or stringy.
How to reduce bruising and browning
We can help reduce the chances of bruising and browning by handling produce correctly from point of purchase to the dinner table. Here are some tips:
• Choose fruits and vegetables that are free of bruises and other damage.
• Avoid pre-cut fresh produce, but if you do buy it, be sure it is refrigerated or stored in ice.
• Separate any fresh produce from raw meat, seafood, and poultry in your grocery cart, in bags, and in your refrigerator.
• Place produce in coolers or use ice packs during transport to home (unless it is a very short drive).
• Once at home, store all produce immediately in a refrigerator set at 40 degrees F or lower.
• Don’t wash any produce until you plan to use it.
• Always use separate cutting boards, cooking utensils, and prep dishes for produce versus meats, poultry, and seafood.
