Impact of Cooking, Storage and Processing affect vitamin D

How do cooking, storage, or processing affect vitamin D?

Since cow�s milk-containing foods are an important source of vitamin D in the United States, and since most dairy products are not only fortified with vitamin D but also pasteurized prior to retail sale, there is good research data on the stability of vitamin D under different heating and storage conditions. Researchers have found virtually no loss of vitamin D following pasteurization of processed cheese under normal commercial conditions. They have also found a vitamin D loss of about 25-30% when cheese is exposed to an oven temperature of 450�F (232�C) for approximately 5 minutes.

Since foods like frozen cheese pizzas are often cooked in the oven at temperatures between 400-450�F (204-232�C) for approximately 20 minutes, this research tells us that we can expect at least one-fourth of the vitamin D to be lost during the pizza re-heating process. This percentage of vitamin loss is still relatively low, however, in comparison to similar heating of other foods and loss of other vitamins (especially less heat-stable vitamins, like vitamin C).

Storage of cheese over a 9-month period at temperatures ranging from 39-84�F (4-29�C) have shown virtually no loss of vitamin D, also underscoring the relative stability of this vitamin.