While the properties of cranberries for warding off urinary tract infections have been well documented, researchers at the Worcester Polytechnic Institute (WPI) are now reporting a surprise finding that expands the red berries’ healing characteristics. They discovered that cranberry juice cocktail evidently helps block a strain of the bacteria Staphylococcus aureus from bringing on staph infections, which can range from minor skin rashes to serious bloodstream problems. One particular strain, Methicillin-resistant S. aureus (MRSA), is a growing public health concern because it doesn’t respond to most antibiotics.

To cause an infection, bacteria must first adhere to host tissue, and then gather in colonies to form a biofilm. In their study, the scientists found that in participants who had recently consumed cranberry juice, the ability of bacteria such as E. coli and S. aureus to form biofilms was significantly decreased, thus reducing the chance of contracting a urinary or staph infection. “We saw essentially no biofilm in the staph samples,” reports Terri Camesano, a WPI professor of chemical engineering.