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Originally published October 25 2007

Propolis could be used as a natural, non-toxic food preservative

by David Gutierrez, staff writer

(NaturalNews) Extract of propolis may function as a natural antibacterial preservative, according to research conducted by scientists from the National University of Technology in Argentina and published in the journal Food Chemistry.

Researchers applied extracts of Argentinean propolis to cultures of E. coli bacteria. They found that this extract inhibited bacterial growth at an average minimum concentration of 14.3 milligrams of soluble compounds per milliliter of the most active propolis. This concentration was effective on E. coli populations as high as 10,000 cells per milliliter.

According to lead author Enzo Tosi, this concentration is safe for human consumption. "Most propolis components are natural constituents of food and recognized as safe substances," he said.

The researchers say that a safe dose is probably 1.4 milligrams of propolis per kilogram of body weight per day (0.63 milligrams per pound), which translates to approximately 70 milligrams per day for an adult.

Propolis is a waxy resin that bees collect from plants and use to seal cracks or other holes in their hives, or to seal away foreign substances (like animal carcasses) that are too large to remove. The composition of propolis varies widely depending on the individual hive, the region where the hive lives and even the time of year. This has made it difficult to evaluate propolis' effects with clinical studies.

Nonetheless, there is a substantial market for propolis as a health supplement, and it has been found to be useful in treating inflammations, minor skin wounds, ulcers, bacteria, viruses and fungus. It has also been said to improve heart health and reduce cataract risk. However, the Argentinean study is the first to test its use as a preservative.

A growing reluctance among consumers to use synthetic preservatives, which are often derived from industrial chemicals, has led to a boom in natural preservatives research. Food companies have been looking into rosemary extract, for example, as an alternative to synthetics.

The current worldwide market in food preservatives is estimated at $574.8 billion, and will likely reach $710 billion by 2008.

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