Can High-Power Ultrasound Protect Produce From Pathogens?
Perfectly sanitized dimpled spinach leaves or tender greens like baby lettuce has been high on the wish list of the $3.1-billion bagged salad industry since its inception. The race to develop better wash systems for cleaning took off in earnest in 2006, after the high profile E. coli O157:H7 outbreak linked to bagged spinach killed five people and sickened more than 200, leaving the leafy green industry with a black eye and an ego-bruising $350-million price tag in recalls and lost sales.
Advances to date in cleaning salad greens have mostly centered on chlorine-based washes and plenty of testing throughout the supply chain. But for organic salad producers, a wash additive may not be an option because it has not been approved for organic use. Among the most promising outside-the-bag solutions? High-power ultrasound. When applied to leafy greens, high-powered ultrasound creates millions of tiny bubbles along a leaf’s surface. As they burst at a rate of a thousand times a second, they provide high-energy shock waves that can get into the leaf’s nooks and crannies to dislodge pathogens, which are then whisked away in the sanitized wash.