By Ben
Coxworth
March 03, 2021
Facebook
Twitter
Flipboard
LinkedIn
While it's
important to rinse leafy vegetables before eating them, the use of regular water
alone may not be sufficient to dislodge harmful bacteria Photo credit: Denisfilm/Depositphotos
VIEW 1 IMAGES
First of all, plain ol' tap water
can't necessarily dislodge all of the bacteria from leafy vegetables, yet the
use of cleansers such as soap or disinfectants also isn't recommended. Not only
is it difficult to completely rinse the chemicals out of all the leaves' nooks
and crannies, but bacteria deep within those same crevices may get missed by the
cleansers.
Instead, researchers at Britain's
University of Southampton tried using a continuous stream of water that carried
microscopic bubbles and acoustic waves down from an upstream source onto
contaminated leafy vegetables.
"The sound field sets up echoes
at the surface of the leaves, and within the leaf crevices, that attract the
bubbles towards the leaf and into the crevices," says the lead scientist, Prof.
Timothy Leighton. "The sound field also causes the walls of the bubbles to
ripple very quickly, turning them into microscopic 'scrubbing' machines. The
rippling bubble wall causes strong currents to move in the water around the
bubble, and sweep the microbes off the leaf."
It was found that six days after
receiving a 2-minute ultrasonic water treatment, microbial loads on contaminated
spinach leaves were "significantly lower" than those on leaves rinsed with plain
water at the same velocity, for the same amount if time. And importantly, the
scrubbing micro-bubbles appeared to cause no damage to the leaves.
While it's unlikely that our
household taps will be equipped with ultrasound transducers anytime soon, the
technology could be utilized by produce suppliers such as Vitacress, which
funded the study.
A paper on the research was
recently published in the journal Ultrasound
in Medicine and Biology.
Source: University
of Southampton