The American fruit and vegetable trading company treats Portobello mushrooms and other varieties of mushrooms with short light flashes. In this way the vitamin D levels of the mushroom varieties are raised significantly.
Dole puts the Portobello on the market with a reference to the raised vitamin D levels and low calorie and fat content. Later in the year the normal mushroom varieties may also be put in these new packages. Gary Schroeder, director of Dole Mushrooms says in the magazine The Packer: “Research has shown that light can boost the vitamin D levels in a mushroom. Nature is trying to do this, and we’re just allowing it to happen". Mushrooms naturally offer 4% of the recommended daily vitamin D allowance. The human body is naturally capable of generating vitamin D through sun stimulation, but for people who spend a lot of time indoors this might not be enough.
Besides the American company Dole, Montery Mushrooms, also from the US, is working on ways to raise vitamin D levels of mushrooms with the help of light.