A recent study published in the Proceedings of the National Academy of Sciences highlights the risks associated with cutting onions, particularly concerning the potential spread of pathogens. Onions tend to be more clonal with pathogens. They learned their star power after a huge E. coli outbreak in 2024 that public health officials traced to consumption of the fruits. This outbreak led to 104 reported cases of illness in 14 states, ending with one of those illnesses tragically leading to death.
The recently published research by Zixuan Wu and co-authors deepens our understanding of the mist formation behavior of onions when sliced. Brown explained that onions are capable of ejecting microscopic droplets at incredible velocities. This creates a new health risk if they are not properly managed within the home.
Understanding Onion Mists
When sliced, these vegetables release fiercely sulfurous aerosols, which have been shown to travel more than two-thirds of a meter wide into the air. According to the research, one of the biggest surprises was the cutting process itself creating such small droplets. These droplets move in the estimated velocity range of 5 to 40 m/s. As the knife passes through the onion’s outer layer, it quickly forces a spray of droplets into the air. These droplets can carry harmful bacteria, such as E. coli and salmonella.
Mechanical models have shown that violent human coughing has the potential to propel droplets at velocities in excess of 20 meters per second. Onion mists are shot out at a higher velocity. This grim statistic underscores the great importance of washing and peeling onions. Through simple actions like these, we can make major progress towards eliminating health hazards in the kitchen.
Moreover, the study emphasizes that if proper precautions are not taken, cutting onions can facilitate the spread of bacteria around a kitchen. This last finding is especially troubling for restaurants such as McDonald’s, where cross-contamination has the potential to cause millions of people to get sick.
Techniques to Reduce Droplet Spray
The research provides useful advice on how to cut down the level of droplet spray produced during onion preparation. It recommends that slowly chopping onions using a puncture-proof blade type would greatly reduce aerosol spread. An average blade sharpness of 13 μm greatly mitigates spray production. A cutting speed of 2.0 meter per second is part of this improvement.
Onions, for example, give professional chefs the opportunity to practice their desired slicing cadence, which is usually around 1 meter per second. It’s an innovative approach that prioritizes accuracy and security in culinary arts. Coating onions in oil before chopping can help form a barrier. This technique allows for even less aerosol release and promotes increased kitchen food safety.
In light of recent foodborne illness outbreaks associated with tainted onions, using these techniques is more important than ever. They call on us to be more conscious and cautious in our food preparation habits.
Implications for Food Safety
These results have important applications to the everyday home cook as well as culinary professionals. By understanding how cutting techniques affect aerosol dispersion, individuals can adopt better practices that mitigate the risks associated with handling onions.
Since onions are a common ingredient across the world, proper preparation practices are key to keeping them safe and avoiding future outbreaks. Reducing marketers’ sprays during onion slicing improves health and safety for kitchen employees and extends that protection to customers as well.