New technology for rapid in-house detection of foodborne pathogens

by CEA inSight

Contrary to some claims, CEA facilities aren’t immune to foodborne human pathogens such as salmonella, listeria and E. coli. While tracking capabilities in the face of outbreaks have improved exponentially, they’re still not fast enough for affected consumers and producers. But a peer-reviewed article recently published in the Journal of Food Safety details a novel new platform that can detect these pathogens on produce in just three to six hours — before product hits stores or consumer tables.

Noninvasive multi-spectral imaging

This food safety advance results from work by University of Delaware (UD) faculty researchers Harsh Bais and Kali Kniel, former UD graduate student Nick Johnson, and Anthony Ragone of Delaware-based startup Biospection, funded by a Delaware Biocenter for Advanced Technology grant for scientific technology and intellectual property.

The multi-spectral imaging device developed by the team monitors plant sentinel response to reveal early changes in plant tissue, such as a drop in chlorophyll, at a stage otherwise invisible to the naked eye. Eventually, growers may be able to use this technique to scan produce on in-house conveyors before it’s transported to stores.

“Because these bacteria are not true pathogens for plants, you cannot physically see early signs that the plant is under stress,” said Bais, UD professor of plant biology. “Biospection’s technology allows us to say, very quickly, if the opportunistic human pathogen is present in the plant.”

The new noninvasive technique scans leaves using multispectral imaging and deep UV to sense changes that indicate when the plant is under attack. When viewing benign bacteria, researchers observed no change in plants. But with harmful human pathogens, the affected plant showed significant differences very early on.

“Using listeria as an example, in three to six hours, we see a sharp drop of chlorophyll pigments,” Bais said. “That’s a strong signal that the plant is responding physiologically — a marker of unusual bacteria.”

Commercial availability and future applications

While the new technique is not yet commercially available, expect that to change fairly soon. Biospection was awarded a 2022 National Science Foundation Small Business Innovation Research grant to further develop and commercialize the new technology into a real-time imaging sensor for disease and stress in plants. The company is already working with CEA growers to embed the imaging sensor into vertical farm racks and drones for outdoor crops.

“Working with UD, we’ve laid the scientific foundation to create better instruments,” Ragone said. “We’re working toward an instrument that’s portable, automated and can give an answer in a matter of seconds.”

For future research, Bais may pursue more work to determine if this technology can differentiate between different microbes. “If the sentinel response is different from one microbe to the other, that gives us the identity of the microbe based on plant sentinel response. We haven’t gone there yet, but that would be the ultimate achievement,” Bais said. “In one sentinel, then you could differentiate between what benign and harmful microbes do in terms of one sentinel.”

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