Bread Mold Experiment

This biology experiment requires you to gather some background information before starting with the research. Once you know what the organisms called molds are, understanding the activity would be easy.

Bread Mold Experiment
Bread Mold Experiment

How to Do Mold Bread Experiment


A piece of bread kept under moisture and high temperature develops mold on its surface.

Materials Needed

  • Water
  • Slice of bread
  • Plastic zipper bag
  • Marker
  • Masking tape
  • Pen
  • Notebook
  • Camera (optional)


  1. Sprinkle water on the slice of bread.
  2. Put the bread in the plastic bag and zip it.
  3. Use the tape to secure it further.
  4. Write today’s date on the tape with the marker.
  5. Leave the bag undisturbed for 7 days in a warm place outside the house.
  6. Track the growth of the mold by checking the sample every day. Collect data in the notebook on the size and color of the colony. You can also take a photograph of the bread each day.
  7. In the end, throw away the bag with the moldy bread without consumption or inhalation near it.

You Can Also Try Out

  1. Instead of just 1 slice, take 3 slices of bread and mark them as A, B and C with the marker on the masking tape. Repeat the process by placing one in the refrigerator, one in a dark room and the last one in a sunny place. Observe and analyze the rate of mold growth under the different conditions of temperature and light.
  2. Check the results by keeping one of the variables like temperature constant for the 3 samples mentioned above but altering the type of bread in the different samples.
  3. Instead of adding moisture to the 3 slices as indicated in the steps above add different amounts of lemon juice or sugar to the slices. How does that affect the molding on the bread? What happens if you add salt?

For accurate measurements, you can take the help of a plastic grid to check how many squares or cm of it gets covered by the mold. While creating the lab report for your science experiment you can plot that data along the Y-axis and the no. of days along the X-axis on a graph paper.

Mold on Bread Project Video

What Is Happening? A Conclusion

Mold is a fungus that best grows in dark, moist and warm conditions. It feeds on organic matter like bread while decomposing the same. Hence it is harmful to consume the moldy bread or even inhale the smell as mold spores could enter the body in that way. Adding salt inhibits the development whereas sugar enhances the method. Types of bread with high moisture content like rye, oat, Boston and other dark breads mold faster than the drier and denser varieties.

Some Interesting Facts

Many food industries depend on molds to produce food materials like soy sauce, country cured ham, certain types of cheese, etc. They need to know the favorable conditions for fast culture. On the other hand, there are other food industries that take measures to preserve the produce from molds. They utilize the knowledge of the unfavorable situations of infestation.

If you are planning to demonstrate molds growing on bread at a science fair, it is best to perform the experiment beforehand and exhibit the resulting samples for all to see with due explanation of the method adopted.


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