Cranberries May Provide Protection Against Bacteria Associated with Food Poisoning

18/09/06 E. coli is a common cause of food-borne illness -- every year, an estimated 76 million cases of food-borne illness and 5,000 associated deaths occur in the United States. Now, there's a natural alternative to combat certain strains of E. coli bacteria -- cranberries.

Compounds in cranberries called proanthocyanidins (PACs) have been known to "disable" certain harmful bacteria in the body, helping to ward off infections. For example, in the urinary tract, cranberry compounds disable certain E. coli bacteria so that they can't attach to bladder cells and are harmlessly flushed out of the body. Other data has suggested that this "anti-adhesion" mechanism of action found in cranberry PACs may also help prevent certain bacteria from adhering to the stomach and the mouth, reducing the risk of stomach ulcers and gum diseases.

According to a new laboratory study conducted by researchers from Worcester Polytechnic Institute, cranberry PACs disable certain E. coli bacteria and may prevent the attachment of microorganisms that cause infection by changing the shape of the bacteria from rods to spheres, altering their cell membrane, and making it difficult for bacteria to make contact with cells, or from latching onto them should they get close enough.

Another study shows cranberries may offer a unique line of defense with their ability to reduce the growth of certain E. coli and other types of bacteria found in food and in the body. Researchers at the University of Maine added cranberry concentrate to samples of food tainted with several types of bacteria that frequently cause food related illness. After several days, scientists discovered that the cranberry concentrate significantly reduced the growth of certain E. coli and other bacteria in the food samples.

"Incidences of E. coli contamination and food-borne illness seem to be occurring more frequently throughout the United States," said Dr. Vivian Chi Hua Wu, Assistant Professor, Department of Food Science & Human Nutrition at the University of Maine. "Cranberry's antimicrobial effect offers considerable promise as a natural and effective tool to prevent such outbreaks."

Some E. coli bacteria are now becoming increasingly resistant to the commonly prescribed antibiotics used to treat them. Cranberries may reduce the need for antibiotics by preventing the initial infection. Fewer infections may mean fewer antibiotics.

Cranberry PACs anti-adhesion activity is primarily due to their unique A-type structure. While some other foods only contain the more-common B-type PACs, it is cranberry's A-type PACs that are responsible for this anti-adhesion mechanism of action. Since cranberry PACs also function as antioxidants, they provide a dual anti-adhesion and antioxidant health benefit. With more PACs and antioxidants per gram than most fruit, cranberries ward off certain bacteria and bolster the body's defenses against free radical damage that can contribute to many chronic diseases including heart disease.

There are a variety of ways to get the cranberry's anti-adhesion benefits. One eight-ounce glass of cranberry juice cocktail contains just as many PACs as: 1/4 cup of fresh or frozen cranberries, 1/3 cup of sweetened dried cranberries, or 1/3 cup of cranberry sauce.