Foods with a medicinal function are part of a growing trend in food product marketing called "nutraceuticals," or functional foods. Food scientist Robert Beelman believes ordinary Agaricus mushrooms could be marketed as nutraceuticals as well. Several years ago, when Beelman added calcium chloride to mushroom irrigation water to improve color and increase shelf life, he discovered the mushrooms absorbed about twice as much calcium as normal. He and graduate student Matt Spolar later theorized that mushrooms also could absorb other minerals, such as selenium. Selenium, a rare element found naturally in the Earth's crust, plays a crucial role in the human body as part of a system of enzymes that enhance the ability of a normal cell to eliminate free radicals and foreign compounds, such as carcinogens in automobile exhaust and cigarette smoke.

Spolar and Beelman added sodium selenite to irrigation water for an experimental Agaricus crop at Penn State's Mushroom Research Center and discovered that predictable amounts of selenium could be absorbed into the crop. Further tests showed that the mushrooms could absorb enough selenium to achieve the current recommended daily allowance in one 84-gram serving -- about 5 mushrooms -- with no reduction in crop yield. "The selenium also made the mushrooms last longer," Beelman explains. "It makes sense, because selenium reduces damage from oxidation, which is a major cause of deterioration in mushrooms."

Beelman then collaborated with Penn State nutritionist John Milner in a cancer trial using laboratory rats. For two weeks, the control group of rats was fed a normal diet, another group received a diet with normal mushrooms added, a third group received a diet with selenium-rich mushrooms added, and the fourth received a diet containing sodium selenite. The rats were then fed a carcinogen and examined for changes in their DNA that are precursors for cancer. "A selenium-rich mushroom diet reduced damage to the rats' DNA by about half," Beelman says. "Selenium-rich mushrooms can become a significant source of dietary selenium, and more importantly, they may significantly modify cancer risk."

Beelman and Spolar are currently working to enrich mushrooms with selenium and other minerals without treating irrigation water. "Selenium is toxic in large doses," Beelman says. "Adding it to irrigation water means that producers would have to closely monitor all irrigation to prevent adding too much selenium." Instead, the researchers developed a process of adding selenium to the mushroom compost by treating the nutritional supplement growers add to compost at the same time it is "seeded" with mushroom spawn. The process produced selenium levels similar to those in irrigation methods. "Enriching the nutritional supplement with selenium takes away the element of chance from the grower," Beelman explains. "Selenium levels in the supplement can be analyzed before shipping and could give growers more consistent quality control. Consumers may not be ready yet to embrace selenium-enriched mushrooms as nutraceuticals, but the concept of growing mineral-rich mushrooms is legitimate. Our goal is to create a nutritional identity for mushrooms, like Vitamin C has for orange juice."

Although marketing new mushroom varieties and improving Agaricus mushrooms are priorities for the mushroom industry, growers are just as concerned about solving production and disease issues that have threatened the industry over the last decade. Representatives from the industry approached both key legislators from their districts and Penn State's College of Agricultural Sciences to help. According to plant pathology department head Elwin Stewart, the University played a major research role in building the state's mushroom industry from the 1930s to the 1980s. Funding cuts and other issues reduced that role after the mid-'80s, but the mushroom industry decided to change that.

In 1995, Stewart formed an advisory board of mushroom industry growers and representatives from related industries to identify and prioritize issues that could be addressed through Penn State research. At the same time, growers asked legislators to provide funding to support research. As a result, a multimillion-dollar initiative called Mushroom Industry Farmer-Based Applied Research (MIFBAR) targeted three areas for intensive Penn State research projects: green mold, reducing mushroom compost odors, and solving problems associated with spent mushroom substrate.