Extracts from culinary ingredients such as green tea, grape seed and spices could be used instead of chemical preservatives as a way to protect against foodborne pathogens like Listeria, according to researchers at the University of Arkansas.

A newsletter from the Food Safety Consortium at the University of Arkansas Division of Agriculture recently reported that food processing companies might soon have such natural alternatives.


In a series of trials, researchers from the University of Arkansas said they applied extracts from natural sources including green tea, grape seed, and nisin, a bacteriocin recognized as a safe food preservative, to chicken and turkey hot dogs. In performing the experiment, researchers used a combination of 75 percent of the chemical preservative and 25 percent natural plant extracts.

According to Navam Hettiarachchy, the University of Arkansas food science professor who supervised the project, the results were encouraging.

When combined with lower levels of chemical preservatives, the natural plant extracts in green tea and grape seed inhibited the growth of Listeria monocytogenes to undetectable levels, Hettiarachchy said.

Importantly, Hettiarachchy explained that “the chemical preservatives can be partially or wholly replaced by natural plant extracts when the extracts are combined with other technologies such as heat treatment, electrostatic spraying or nanotechnology.”

She added of those three technologies, nanotechnology would most likely work best as a delivery system for the natural antimicrobials.

“If we can deliver these antimicrobials in nanoparticles, we will have better pathogen inhibition at a much lower concentration of the antimicrobial over a longer period of time,” Hettiarachchy said.  Essentially, this would allow for the least amount of plant extracts to be used with the greatest capacity for pathogen reduction.

This development could prove to be advantageous not only for food processors, but for consumers as well.

Currently, food preservation systems often use chemicals and heat treatments to reduce the risk of bacterial food poisoning outbreaks and food spoilage, but chemicals can alter the taste of the product and, moreover, can compromise food safety.

The findings of Hettiarachchy’s research team indicate that food can instead be treated with natural substances in order to eliminate the risk of potential pathogens during the processing stage, creating a benign alternative to the use of chemicals.

The Food Safety Consortium, established by Congress in 1988 through a special Cooperative State Research Service grant, works on the pressing technological needs of the food industry.

Its primary function is to develop the necessary tools for a safe food supply, including “technology to rapidly identify contaminants, methods to evaluate potential health risks, risk-monitoring techniques to detect potential hazards in the food chain, and the most effective intervention points to control microbiological or chemical hazards.”

Consisting of researchers from the University of Arkansas, Iowa State University and Kansas State University, the Consortium allows each university to focus its studies on a particular animal species. For instance, scientists at the University of Arkansas concentrate on the study of poultry, while Iowa State University targets pork and Kansas State University, beef.

The food industry presents a great demand for technology that would improve food safety.  It wants what is considered to be cutting-edge technology.  Hettiarachchy is confident the use of nanotechnology to introduce natural antimicrobials to meat would provide just that. “The food processing companies are interested in the state-of-the-art delivery system with the natural antimicrobial extract for better pathogen control,” she added.

Before food processing companies adopt natural antimicrobials for use in their products, however, further development will be required.  As Hettiarachchy confided, “Industry takes time to decide.”