Which fruits and vegetables should and shouldn’t be stored together

You brought home all your fresh produce from the supermarket or farmers market. Now is the time to unpack.

The task seems easy enough, but you’d better think about it at least a little. What you store, where and when, is important in part because of ethylene, a plant hormone responsible for ripening and which can, over time or under the right circumstances, reduce shelf life and cause spoilage, says Laura Strawn, associate professor at the Virginia Department of Food Science and Technology at Tech.

The presence of ethylene and variations in how fruits and vegetables release or react to it mean that not all products work well together. Here’s what you need to know and why it might not be a big deal if you get it wrong sometimes.

Which fruits and vegetables are friends in the fridge? They don’t need to go all in the crisper. Photo: iStock

Sensitive ethylene v ethylene producers

When it comes to ethylene, “Technically, the generalization of saying that fruits are the producers and real vegetables are sensitive is a safe logic to follow,” Strawn says.

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Bananas, melons (like melon, not watermelon), apples, tomatoes And avocado they are great examples of ethylene producers, says Strawn. But it’s a little more nuanced than one / o, as many ethylene producers are also hormone sensitive – they produce it to trigger their own ripening process. Carrots, broccoli, vegetables And cucumbers are examples sensitive to ethylene that do not produce their own ethylene.

Of course, the division isn’t quite as clear-cut once you dig a little deeper. “Humans love to classify,” says Christopher Watkins, a professor at Cornell University’s School of Integrative Plant Science Horticulture Section. But there are many exceptions and variations. Production and sensitivity to ethylene may vary by variety or stage of maturity. Some apples they produce a lot of ethylene and are very sensitive to it (anyone who has had a soggy one can understand that), while varieties like Fuji and Pink Lady produce far less, Watkins says.

If you’ve ever heard of the advice not to store potatoes and onions together because ethylene will cause one or the other to sprout, that’s only partially true.

A green tomato it will be very sensitive to ethylene as it is not ripe yet, but a red less. Watkins notes that farm-market heirloom tomatoes that appear to transform the moment you look at them are more sensitive to ethylene than store-bought varieties.

Climatic vs non-climatic

There is also another way to classify fruits, depending on whether they ripen after being harvested. These are called climatic, and will respond to the presence of ethylene by producing more ethylene. The ethylene producers I mention above are climacteric, just as they are stone fruit, pears, kiwis And mangoes. (This is also why articles like bananas And tomatoes they are often harvested unripe and then left to ripen on their own or treated with ethylene for sale.) In climacteric fruit, starch continues to turn into sugar, improving texture and flavor.

Non-climatic fruits “Don’t respond to ethylene with its increasing production of ethylene,” says Harold McGee About food and cooking. While they won’t get sweeter, other enzymes can make them softer or improve the aroma. Citrus fruits, grapes, cherries, berries (blueberries are somewhere in between), pineapple And watermelon are examples of non-climatic fruits.

Keep in mind that just because one type of product doesn’t respond to ethylene doesn’t mean it’s immune to spoilage. Bacteria, mold, yeast, humidity and temperature can reduce the shelf life of fruits and vegetables.

What does all this mean for archiving?

“When you’re thinking about storing fruits and vegetables, in general, you want to avoid storing ethylene-producing products close to those that are sensitive to ethylene,” says Alexis Hamilton, a postdoctoral associate in Strawn’s lab.

Exposure to ethylene can cause broccoli and kale to turn yellow and carrots become bitter, Strawn says. Lettuce and other vegetables, as well as some herbs, can also discolour or wilt in the presence of ethylene.

Heirloom tomatoes are more sensitive to ethylene than store-bought varieties.

Heirloom tomatoes are more sensitive to ethylene than store-bought varieties. Photo: Marco Del Grande

“Reducing the unwanted effects of ethylene at home is as easy as storing these products in separate drawers or bags and in separate places in the refrigerator,” says Hamilton.

“Many refrigerators come with multiple types of sliding containers designed to store fruit and vegetables to preserve their quality and freshness based on humidity requirements, but you want to be sure to control the production of ethylene within these as well.”

So consider keeping ethylene sensitive products in your refrigerator’s vegetable basket, where you can make sure there is enough moisture to keep things from moving.

In the fruit basket, where you can typically open a vent to let the moisture escape, you can store your non-climatic fruit and even seasoned items, such as Peaches.

Apples they are fine in colder places, so consider storing them in the back in a bag, where they will also be separated from the more ethylene-sensitive items. The good news is that refrigeration also slows down ethylene production.

For items you are storing on the bench that you plan to eat soon or that need to ripen, you don’t have to worry too much about taking extreme measures to separate items that may be more or less sensitive to ethylene. Watkins says that the outdoors in your kitchen or dining room has plenty of ventilation to allow ethylene to dissipate, although, as Strawn notes, bananas they are particularly susceptible to ripening in the presence of other bananas.

Tight spaces – a bag, closet, or refrigerator drawer – are somewhat different, as they can trap ethylene and accelerate ripening or germination. (If you’ve ever heard the advice not to store potatoes And onions together because ethylene will sprout one or the other, this is only partially true. Watkins says the main reason for keeping them separate is to prevent potatoes from picking up odors from onions.)

But can trapping ethylene also be a good thing? This is the next step.

How to use ethylene to your advantage

You’ve probably heard tips on how to put fruit in a brown paper bag to speed up the ripening process. In this case, conventional wisdom checks. By bagging such climate products as kiwi, avocado or mangoes, as Strawn did during his food safety research, you are trapping ethylene gas which will trigger the production of even more and, voila, mature. Bagging alone is often sufficient, although you can add an apple for good measure if you wish.

How much does it really matter?

Much of the storage recommendations are based on experiments and observations done in highly controlled scientific environments, Watkins says, but “the real world is very different.” This means that not everyone will follow the advice and maybe it won’t necessarily be a problem.

Will the typical person always notice or worry about some yellowing broccoli or slightly harder asparagus? As Watkins pointed out in a report, the damage caused by ethylene is more relevant to growers and large-scale markets. A home kitchen is not the same, especially in terms of the quantity of products present and how long they are stored.

That said, “In the end, we want people to do the right thing,” Watkins says. In addition to being equipped with a basic knowledge of the differences between the products and the little things you can do to deal with them in storage, his main advice is to pay attention to what you have so that you can eat it fresh and ripe, or at least move it to the refrigerator if necessary.

“If you are worried about food waste, your number one priority would be to think about what’s in your refrigerator.”

Washington Post