Busting the myth about leftover onions

Published 8:54 am Wednesday, June 6, 2018

Question: Is it OK to use leftover cut onions? I recently read an article that cut onions are magnets for bacteria and can cause food poisoning.
Answer: That myth has been circulating by email and social media for some time now. It’s not true. The message claims that left over, cut onions should not be used the next day, because they become highly poisonous because of bacteria growth, turn toxic and lead to adverse stomach infections. The message is not a fact, there is no scientific evidence to prove this claim.
Overall, there are no safety precautions that are unique to an onion that wouldn’t hold true to apples, carrots or anything else you would get out of a garden. These rules include thoroughly washing your hands and kitchen tools and wiping down counters with sanitizer before beginning the food prep process so that you don’t introduce outside contamination.
When you follow these safe food practices, cut onions “can be stored in the refrigerator in a sealed container or ziplock bag for up to 7 days,” said the National Onion Association.
Ellen Steinberg, PhD, R.D., L.D., food safety specialist, says, “There is no validity [to this myth] at all. For starters, the chemical makeup of onions just doesn’t support bacteria growth,” she explained. Their low pH (i.e. acidic nature) and low protein content mean they are not an ideal breeding ground for germs, viruses or other pathogens. In fact, the opposite is true: onions contain compounds that have antibacterial properties.
“When cut, onions release compounds that do not promote pathogen growth,” the National Onion Association said in a statement published on their website. “The Center for Food Safety at the University of Georgia states, juice released from cut onion is known to kill or inhibit the growth of several types of microorganisms, including some of those capable of causing food poisoning in humans.”
According to the National Onion Association, this onions-are-poisonous myth originates from several different sources, including a folk belief from the 1919 influenza epidemic that claims cut onions left around the house will combat the flu virus, and a 2008 blog post via Dinner With Zola that purports onions and potatoes cause more food poisoning than spoiled mayonnaise. The blog post, which has since been deleted, triggered Chicken Little-esque chain emails and sensationalized warnings that although officially debunked, still exist on the internet today.
So, are onions a high risk food with respect to food safety and food borne illnesses? Nope.
The onion myth? Busted.
Onions are safe as long as they are handled properly.
Vickie Clark is the Director of the Carter County UT Extension Office and also serves as the Family and Consumer Sciences Agent. If you have questions or need any information related to Family and Consumer Science contact her at the UT Extension Carter County, 824 East Elk Ave., Elizabethton, call 542-1818 or email at vclark@utk.edu.

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