News | Aug 9, 2017

Natick Labs invented a sonic scrubber to keep chow halls clean, listeria study demonstrates superior performance

Army sampling wand uses acoustic energy to blast potentially dangerous pathogens from surfaces, available for commercial license

News Article Image of Natick Labs invented a sonic scrubber to keep chow halls clean, listeria study demonstrates superior performance

PFC Asia Johnson, culinary specialist, sets vegetables on serving lines at Fort Stewart in 2017. (Joshua Petke/Army)

This high-tech sonic scrubber might look like it belongs in the toothbrush or kitchen aisle at the grocery store, but it’s getting attention from microbiologists as a tool in keeping the public safe from deadly pathogens.

It’s called the “handheld implement for removing microbiological matter from a surface,” according to its patent, and was invented in 2009 by Patrick Marek, a research microbiologist, and Joshua Magnone, supervisory food technologist, at the Army’s Natick Soldier Research, Development & Engineering Center.

The portable sonic scrubber is battery powered and has a pump inside that can suck up microbiological pathogens like E. coli and listeria living on food preparation surfaces after they’ve been blasted off by the push-button sonic horn, which helps address an issue for military and civilian personnel charged with food safety and sanitation–when is clean really clean?

“If bacteria are not found with a traditional swab you are probably thinking we are all set and have done our due diligence and have cleaned and sanitized correctly. What if what we didn’t see was the real issue, bacteria remaining on the surface in a scratch or a seam and hiding from detection,” Marek said in a statement to TechLink.

Army sonic scrubber

Conceptual illustration of the Army’s sonicating swab

Traditional cotton swabs may be soaked in a liquid to help remove the encrusted biological matter, but such measures have limited success. That’s why the research team added the tried-and-true ultrasonic cleaning technique.

Pushing the button on the wand activates an ultrasonic transducer, which sends acoustic energy into the base fluid (water) and spontaneously produces cavitation bubbles.

The tiny bubbles implode, generating a fluid jet, which dislodges microbiological materials. After that, drawing the syringe plunger sucks up a sample from the scrubbing tip for lab testing.

“This device is focused on going after those stubborn guests that have overstayed their welcome on surfaces for food contact but it also has applications in hospitals, schools, and cruise ships to list a few examples,” Marek said. “The sonicating swab has been demonstrated to be effective in removing and collecting biofilm in a recent publication in Applied and Environmental Microbiology and was found superior to the traditional cotton swab.”

The journal article focused on a study of the sonic swab’s efficacy in sampling listeria monocytogenes biofilms on stainless steel.

“Scanning electron microscopic imaging showed that biofilms remained in the polished grooves of the (steel) coupons sampled with the standard swab but were noticeably absent with the sonicating swab,” the 2017 article reported.

Listeriosis affects about 1,600 people per year in the United States and is usually caused by eating contaminated food. Most people with invasive listeriosis require hospital care, and about one in five people die. If infection occurs during a pregnancy, the bacteria can spread to the baby through the placenta and cause miscarriage, according to the Centers for Disease Control and Prevention.

A patent for the sonicating swabbing device issued in 2012 and it is available for commercialization. To learn more about licensing the Army’s patented technology, contact TechLink for no-cost assistance.

Troy Carter can be reached at troy.carter@montana.edu or 406-994-7798.

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