By: Stephanie Westover
The purpose of this experiment will be to determine how temperature affects the growth of mold on wheat bread. The researchers choose this topic because she thinks it will be beneficial to find a way to keep food from molding. Determining how long bread can be stored before molding can help save money, prevent illness and preserve freshness. The question the researcher will attempt to answer is how freezing affects the rate of mold growth in wheat bread. The information gathered in this experiment may be relevant to those individuals who contend with food borne molds at home, or professionally. Because the rate of mold growth can vary depending on the type of bread tested, the researcher will limit this study to a commonly available variety of wheat bread that can found in most stores. This will make the results of this experiment more relevant to average consumers and it will enable the results to be generalized across a larger selection of commercially produced wheat breads.
Having some understanding of common practices regarding food storage and mold growth, the researcher sought out formal studies of food borne mold growth to help develop my hypothesis. What the researcher discovered was that food storage at low temperature slows many of the enzymatic reactions involved in spoilage and reduces the growth rate of microorganisms. (Microsoft Encarta, 2007) This literature review shows that refrigeration slows the growth rate of mold. Further, the article demonstrated that refrigerators should be kept at temperatures 32 to 40 degrees Fahrenheit to minimize bacterial growth. In this procedure the researcher discovered that refrigeration does indeed slow the growth rate of mold. Many organisms will not grow at all or will grow at a slower rate if stored in low temperatures. While low temperatures are not bactericidal, the low temperatures do slow the growth rate of bacteria. Although a few microbes will grow in super cooled solutions as low as minus 20o c, most foods are well-preserved against microbial growth in the household freezer. (Todar, Kenneth, 2011) In this article it states that even a household freezer can preserve foods against growth of mold if set at the right temperature. The researcher discovered that the zip lock baggie that the freezer in this experiment did in fact preserve the bread against the growth of mold.
The experiment design will be as follows: The researcher will purchase a loaf of commercially produced wheat bread and record the rate of mold growth on that bread over a period of 10 days at three different temperatures. The researcher will use commercial grade thermometers placed in a standard refrigerator, freezer and kitchen countertop to measure temperature. A commercial grade thermometer was used as it is close to the same type used in a typical restaurant. The researcher will place one piece of bread in a clear, sealed zip lock bag and put one of those bags in each of the three temperatures zones. Zip lock baggies were chosen over any other standard container because it was the best choice to keep out any bacteria that might give false results. She will remove each test bag from its controlled temperature zone and measure the mold growth on each piece of bread through the clear zip lock bag using a fractional ruler. The researcher will record those measurements in a log book noting the time, temperature variation if any, and size of mold growth in inches. She will then immediately replace the bag back into its respective temperature zone. The researcher will repeat those measurements for 10 days and summarize my findings at that time. The researcher will be using commercially available wheat bread so that the results of this experiment can be at least partially generalized to all commercial bread products. She will be using common temperature settings throughout the...