Carbondale, IL. -- An Indian spice might hold the key to improving the shelf life of fresh produce and even in curbing E. coli outbreaks.
It sounds like something you'd find in a futuristic kitchen – countertops, cutting boards and knives that prevent cross-contamination by killing bacteria on contact. Ruplal Choudhary, a food and bio-process engineer and associate professor in the Department of Plant, Soil and Agricultural Systems at Southern Illinois University Carbondale, is part of a research team looking at applications of the spice turmeric to do just that: to make food-safe, antibacterial surfaces for food processing, preparation and packaging. The team published its early results this year in the "Journal of Agriculture and Food Chemistry."
Curcumin, the main ingredient in turmeric, forms a phenolic compound – a plant-based chemical compound. This curcumin compound contains naturally occurring properties that make it a powerful antioxidant and anti-inflammatory. This is not news in India, where curcumin is widely used as a medicinal herb. Science, however, has confirmed that the phenolic compounds known as curcuminoids have health benefits and antimicrobial qualities.
Choudhary and a collaborative team of SIU researchers in the colleges of Agricultural Sciences and Science, along with a team under the direction of Victor Rodov from the Agricultural Research Organization at The Volcani Center in Israel, put curcumin to the test as they tried to find a way to use the phenolic compound to create a food-safe, antibacterial surface.
Their initial tests, conducted with the aid of a $100,000 feasibility grant from the Bi-national Agricultural Research and Development Fund (BARD), included other compounds, such as resveratrol found in grapes and hydroxytyrosal found in olives. Curcumin turned out to be the most effective antimicrobial compound. In particular, the researchers tested the compound against E. coli, and found curcumin to be highly effective.
With the aid of $300,000 in continued support from BARD, the team, including Punit Kohli, associate professor of chemistry and biochemistry, and John Haddock, associate professor of microbiology, set out to use the curcumin compound to develop an antimicrobial surface. They employed nanotechnology, a relatively new interdisciplinary science dealing in the realm of the very tiny – smaller-than-microscopic tiny.
The team built nanovesicles for the curcumin compound that adhere to and enclose the compound and bind it to glass and other surfaces. These nano-coated surfaces, when used in food processing, preparation and storage, naturally kill microbes and prevent spoilage. Despite the spicy origin of the compound, the nanotreated surface does not flavor the food that comes in contact with it.
Next, Choudhary wants to use the curcumin compound in active food packaging --- nanocoated packaging that extends the shelf life of fresh produce and other foods with natural antimicrobials and preservatives.
"Where I grew up, our house was surrounded by gardens," Choudhary said. "My father never liked to eat produce that came from the store, especially if it was harvested early and ripened in transit or at the store – he said it had no taste. We know now fresher foods are also higher in antioxidants and nutritive value. My goal is to find practical ways to use this technology to preserve food freshness as well as to create antimicrobial surfaces."
Choudhary will visit the Volcani Center in Israel this spring as the SIU team and Rodov's team near the conclusive stage of the BARD-funded research. They hope to patent the nanocoating process they have discovered, and to continue to broaden its applications for food safety.