|MadSci Network: Genetics|
Hi Joshua, To answer your questions about bread color first: White bread is made with flour that has be ground from just the endosperm of the wheat kernel, while whole-wheat, or brown, bread is made from whole-wheat flour which includes the bran (germ and hull). Whole-wheat flour appears brown because it includes the brown parts of the wheat kernel, while white flour is only the white portion of the kernel. Whole-wheat bread tends to have a stronger flavor than white bread due to the additional components from the whole-wheat flour. Now for the microbial questions: I think you are asking about the types of molds you might see on either type of bread. There are many molds which will grow just fine on either type of bread. Bacteria, in general, will not grow on baked bread because there is not enough water available to support their growth. However, many types of mold do not require as much water as bacteria, so bread is an excellent substrate for their growth as they will not have to compete with faster growing bacteria. What types of molds you see growing on your bread will be a matter of what spores have landed on your bread. If there is diversity in the air, then you will likely see diversity on the bread that has been exposed to the air. Some molds, however, may be able to grow more quickly under the incubation conditions you provide, outcompeteing other molds. Mold spoilage in bread can be slowed by the addition of preservatives. I hope that answers your questions, and you are welcome.
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