sharp Knives, Gentle Cuts: new Research Reveals How to Minimize Onion Tears & Food Safety Risks
ITHACA, NY – For millennia, cooks have battled the tear-inducing effects of chopping onions. Now, a new study from Cornell University published in PNAS reveals the mechanics behind those tears – and a surprisingly simple solution: use sharp knives and employ gentle cutting motions.
Researchers discovered that when an onion’s layers are breached, an initial explosion of mist is followed by a slower seep of fluids. Blunter knives create significantly more droplets and faster sprays as they require greater force, building pressure within the onion’s juices.These forceful cuts can propel droplets at speeds reaching 40 meters per second (144 kilometers/89 miles per hour), posing the greatest risk to eyes.
The study also debunked the long-held belief that chilling onions reduces tear production, finding that colder onions may even worsen the effect.
“These observations were supported by theoretical models that accurately capture independently measured fracture forces,” the researchers wrote in thier published paper.
Beyond tear prevention, the research has implications for food safety. The cutting style influences how pathogens spread,perhaps contributing to outbreaks like the E. coli incident at McDonald’s in the US last year. according to researcher jung, pathogens on the onion’s surface can become encapsulated in droplets and spread during cutting.
The team found that sharp blades and gentle cuts keep the droplet mist below eye level, minimizing exposure. The history of onions in cooking dates back approximately 5,000 years, with even Shakespeare referencing the tear-inducing qualities of the vegetable in Antony and Cleopatra.
