Spicing up food safety

An ancient Indian spice might hold the key to the development of countertops, cutting boards and knives that prevent cross-contamination by killing bacteria on contact.

Researchers at a US university have been investigating applications of the spice turmeric to make food-safe, antibacterial surfaces for food processing, preparation and packaging.

Curcumin, the main ingredient in turmeric, forms a phenolic compound — a plant-based chemical compound — with powerful antioxidant and anti-inflammatory properties. This is not news in India, where curcumin is widely used as a medicinal herb. However, science has now confirmed that the phenolic compounds known as curcuminoids have both health benefits and antimicrobial qualities.

Ruplal Choudhary, a food and bioprocess 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 ways to use the phenolic compound to create a food-safe, antibacterial surface. The team has published its early results in the Journal of Agriculture and Food Chemistry.

Their initial tests included other compounds, such as resveratrol found in grapes and hydroxytyrosal found in olives, but 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.

The team then set out to use the curcumin compound to develop an antimicrobial surface by employing nanotechnology. The researchers built nanovesicles for the curcumin compound that adhere to and enclose the compound and bind it to glass and other surfaces. These nanocoated 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 flavour 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.”