In the ever-increasing quest for healthy foods, more and more consumers are shunning foods laden with chemical additives and preservatives in favor of what they perceive to be cleaner, greener foods. But just because a food is greener doesn’t always make it cleaner, as evidenced by the massive spinach E. coli disaster a few years ago. The concept of naturally-derived preservatives has been an evolving area of focus for researchers at the University of Alberta who recently discovered a compound in mango pits that appears to hold some promise in the realm of natural food preservation.

“Finding alternatives to current food preservatives is an ongoing, important area in food science and preservation,” explained Dr. Michael Gaenzle, a professor in the department of Agricultural, Food and Nutritional Science at the University of Alberta. “It’s a major focus in the department and an obvious area of study because you’d like to replace chemical preservatives and/or improve the safety of foods without damaging them, and that cannot be improved by current methods.”

Dr. Gaenzle has studied natural food preservatives and their effect on E. coli, Listeria and salmonella for a number of years, having previously worked with wheat and barley polyphenols that contain anti-Listeria compounds.

His work with bacteriocins, small proteins produced by lactic acid bacteria, has also shown great potential when it comes to killing Listeria bacteria in meat products.

More recently, Dr. Gaenzle and his colleagues discovered that the tannins found in the pits of mangoes are their most promising area of study. Usually discarded, the tannins from the pits could be used in the wash water that’s used to clean ready-to-eat salads, for instance, as well as fresh juices if the preservative is eventually approved by Health Canada, which has currently approved about 380 food additives for various uses.

As to when consumers might be able to find foods preserved with these natural additives in their local grocery store, Dr. Gaenzle said that reality is still many years down the road. “There are various fields of investigation that are closer to market,” he explained, noting that lactic acid-derived bacteriosides are at the forefront of the movement. “The first big wave of research on these compounds came in the mid 1990s and it took more than 10 years to get the product in the marketplace, after completing the science to ensure it works on real food systems and then finding or building a company that can sell it,” he said.

And then there is also the fact that certain foods are more receptive to treatment with natural preservatives. “For the mango compounds, we’ve started looking at applications with fresh produce, such as fresh cut fruit or spinach salad,” he said. “Fresh produce can be a problem for the food industry. There are frequent, reoccurring outbreaks related to fresh produce because you can’t pasteurize or otherwise preserve it.”

He added that although there is still much research to be done, the mango tannin compound seemed like it would be an effective fit because the plant-derived preservative would be used to preserve another plant.

When asked about the quantifiable market size for natural preservatives, Dr. Gaenzle said it would be complex to estimate how far the reach of natural preservatives could extend. “It’s difficult to assess," he said. “If we find a natural preservative, which makes sure E. coli is eliminated from ground beef, or an antimicrobiral agent, which keeps bread mold-free to replace propionate, then the potential market for those natural preservatives would be huge.”