If someone from Earthbound Farm tells you they’re waiting for ultrasound results, it’s probably not what first comes to mind.
The San Juan Bautista, Calif.-based company is researching ultrasound — long used in the medical industry for scanning, diagnosis and treatment — as a means to sanitize leafy greens.
Will Daniels, Earthbound’s senior vice president of operations and organic integrity, said the producer is looking for an effective wash system that will meet organic standards. Daniels said that high-powered ultrasound is a mechanical process, not a substance, so it would not be subject to organic certification.
Earthbound Farm is working with the Institute for Food Safety at the Illinois Institute of Technology to study adding ultrasound to an organic, citrus-based sanitizing wash.
“Chlorine is effective on pathogens and also cost-effective, but we don’t like the environmental effects of its use,” Daniels said. “The citrus-based sanitizers won’t have that effect, and the high-powered ultrasound provides an additional mechanical action to the sanitizing process. It forms microscopic bubbles on the surface of the leaf, and when they explode and release energy, the action knocks the pathogens off the leaf.”
Earthbound Farm and the Institute for Food Safety and Health have been working on an ultrasound treatment for years and are currently testing the process on spinach and romaine.
“We donated a true commercial wash line to the Institute for Food Safety and Health, so they are testing in a realistic environment, not just bench top,” Daniels said. “If results look good, we’re hoping to be able to test in our own facility late this year.”
Daniels said Earthbound can’t estimate the cost implications of adding ultrasound to a sanitizing line yet because the configuration is still being testing. However, a source from Cavitus — an Australian company that uses high-powered ultrasound in the dairy, olive oil, soy and wine industries — told Scientific American that the investment could cost up to $200,000.
Before Earthbound takes that step, researchers must determine not only whether the technology eliminates things such as E. coli, salmonella and listeria but also if it affects the quality — taste, texture, smell and appearance — of the product.
“That’s why we’re doing the pilot test — so we can evaluate both the efficacy in reducing pathogens and its effect on the product,” Daniels said. “If it winds up making mush of the leaves, it won’t be viable.”