The Effect of Light on Fungal GrowthINTRODUCTIONThe “hot” compound in chilies, capsaicin, affects taste buds, nerve cells and nasal membranes, but it also functions in wild chili plants in other ways continued to be studied. In chili pepper, capsaicin is found in the fruit, secreted via a gland neat the stem, and increases with ripeness. Capsaicin has been found as a protective agent in chilis, fending off fungal growth (Borrell, 2009). It is important that learn about the fungal growth on foods such as chilies for storing and packaging purposes in the food industry and in our own homes. Therefore, we decided to conduct an experiment over one particular factor in storing foods, light. In 1967, Hasan and Magid found several types of fungus produced much more growth in the presence of light. We decided to retest this hypothesis, but on blue cheese in particular. We hypothesized that lighting has an effect on fungal growth. Our null hypothesis was that lighting has no effect on fungal growth. We predicted that fungal growth increases with the amount of light exposure and in the presence of a small amount of capsaicin. If Hasan and Magid finding are true for other fungi, then we should see larger fungal growth with the fungus exposed to light. METHODSThe independent variable was the lighting and absence of lighting. The dependent variable was the fungal growth. We began the experiment with 24 (48 total) replicates of both light and dark plates; however, due to complications, we ended with 21 plates placed in the light and 22 in the dark. Capsaicin Media plates containing 1.0 gram of capsaicin were used. A sterile swab was dipped into autoclaved water and, for each plate, rubbed onto the blue cheese and then rubbed in the center of the experimental plate. In order to measure fungal growth, found the cirmcumference of each fungus by measuring the diameter (in centmeters) with a ruler and then multiplied this value by pi. In Excell we calculated the mean fungal growth of the different treatments, standard deviation, and performed a t-test. We had to perform a 2-tailed t-test because we had different numbers of relicates for each treatment. In order for us to accept our alternative hypothesis, out p-value must be less that 0.05.RESULTSWe found the mean circumference of the fungus with the dark treatment to be 15.215cm and 17.345cm for the fungus with the light treatment. The standard deviation for the fungus in the absence of light was 1.472 and 1.442 for the fungus in the presense of light. We then calculated a t-test resulting in a value of 2.19 x 10-5. Because our p-value is less than 0.05, we can determine that the fungal growth in the two different treatments is statistically significantly different. This evidence is shown in figure 1 showing the difference in the means of the two differnent treatments.DISCUSSIONBecause our experiment provided us with a p-value less than 0.05 we were able to accept our alternative hypothesis and reject our null hypothesis that lighting has no effect on fungal growth. Our results lined up with Hagan and Magid’s finding, therefore, leading us to believe that many other types of fungus, including those that attack chili peppers and blue cheese, thrive in the presense of light. How can we use this information? We can assume that foods are less likely to contract fungal growth if stored and packaged in the absence of light. If we were to re-do the experiment, we would use more replicates to give us even more sufficient evidence. We would also you other types of fungal contracting foods to determine if other types of food attracted fungus thrive in the presence of light as well. We could also further investigate fungal growth in relation to food storage by testing other factors such as temperature and humidity.Figure 1 This figure shows a comparison of the average circumference of the two different treatments, light and dark.1414.51515.51616.51717.518Circumference (cm)Borrell, B. (2009). What’s So Hot About Chili Peppers? Smithsonian.Hasan, Y., Magid, A. (1967). The effect of light on growth and sporulation of certain fungi. Mycopathologia et mycologia applicata. Volume 33, Issue 2 , pp