Fermented milks are consumed in many parts of the world for their acidic taste and health benefits. Some strains of lactic acid bacteria used in making fermented milks produce exopolysaccharides, or EPS – polymers usually high in molecular weight that are made up of sugar residues and are secreted by microorganisms such as bacteria.

Exopolysaccharides are associated with factors such as the smoothness and creaminess of fermented milk products and some may also have chemopreventive properties, meaning they can prevent tumor development.

“Reports in the literature showed chemopreventive activities of polysaccharides from mushrooms. Since the structure of such polysaccharides is somehow similar to that in the bacterial EPS, we expected bacterial EPS to show similar activities,” Hassan says.

He adds that there is a correlation between molecular characteristics of polysaccharides from mushrooms and their chemopreventive activities.

For the study, rats were on diets supplemented with different fermented milks made with differing strains of EPS-producing or non-producing cultures. Rats fed diets supplemented with fermented milk made with two EPS-positive strains and one EPS-negative strain had significantly lowered incidence of colon tumors compared to the other groups.

Distinguished professor Chandradhar Dwivedi, research associate Ekta Bhatia, and graduate research assistant Xiaoying Zhang, all of SDSU’s Department of Pharmaceutical Sciences, also participated in the study, which was recently published in the Journal of Dairy Science.

The SDSU study has important implications because cancer causes about 13 percent of all deaths and is the second leading cause of death in the United States. Colon cancer is the third most prevalent cancer in the United States, accounting for about 10 percent of cancer deaths in men and women.

As researchers learn more, Hassan said, it may become possible to craft dairy products with known disease-fighting properties.