Can Leftover Onion Turn Toxic Overnight?

by Tom Ryan

Like other vegetables, onions don't last forever. They don't, however, go bad overnight. If you've used only part of an onion for a recipe, you don't need to throw away the leftovers for fear of them turning toxic. Instead, simply wrapping and storing them properly can ensure that they last for an additional week, or even longer.

Safely Storing an Onion

Despite urban legend, onions do not turn toxic overnight after they are cut. Similar to other fruits and vegetables, though, a cut onion shouldn't be left out on the counter overnight, simply because the warm temperature and open air make it spoil faster. To make onion leftovers last, wrap them tightly in plastic or seal them in an airtight container, then store them in a refrigerator kept below 40 degrees Fahrenheit. Your leftovers will stay good for as long as 10 more days.

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About the Author

Tom Ryan is a freelance writer, editor and English tutor. He graduated from the University of Pittsburgh with a degree in English writing, and has also worked as an arts and entertainment reporter with "The Pitt News" and a public relations and advertising copywriter with the Carnegie Library of Pittsburgh.

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