Figure 2: Increase in vitamin D2 in sliced white button mushrooms exposed to sunlight under varying conditions of UV intensity (mean ± standard deviation; 1 IU = 0.025 μg). Vitamin D2 in the control (unexposed) mushrooms was < 30 IU/70 g (Table 3) and differed significantly from the corresponding exposed mushrooms in all cases (α=0.05). Letters on data points correspond to experiments in Table 1. Data points with no superscript were for mushrooms placed on aluminum foil, and superscripts indicate mushrooms exposed on 1white paper, 2dark non-stick pan, and 3aluminum pan. DRI= Dietary Reference Intake (20). See Table 3 for results of means comparisons.