| Complexity level: | 4 |
| Project cost ($): | 15 |
| Time required: | 1 hour to prepare, 8 days for observation |
| Material availability: | Very easily found. May be purchased at a supermarket/hobby store. Access to a refrigerator at school or at home is required. |
| Safety concerns: | None |
Hypothesis
Bread mold will grow faster in a warm and damp environment.
Overview
Bread Mold
If a slice of bread was left outside for a few days, some light hairy kind of growth can be seen on its surface. This growth is called bread mold. The bread mold is actually a kind of fungus. The spore from the fungus is being blown about by the wind and it will eventually reach the surface of the bread. Once the spore finds the bread surface, it will start to consume the nutrients and moisture in the bread to grow.
The spores of the fungus that grow on the bread are quite commonly found in our surroundings. There are several types and can be found in different colors and shapes. This is why bread normally spoils very fast. Some of the common types of fungus that grow on the bread are Penicillium, Fusarium, Rhizopus, Aspergillus and Monasus.
Once the mold starts to grow on the bread, it should not be eaten. The roots of the mold will grow very deep into the bread and they will grow again even if the mold is scrapped off. The only way to keep the bread longer is to prevent the mold from growing on the bread surface.
Scientific Terms
Materials
The materials required for this science fair project:
- 5 slices of bread
- Some water
- An airtight plastic bag
- A refrigerator
- A magnifying glass
Procedure
1. For this experiment, the independent variable is the environment in which the bread slice is kept. The dependent variable is the growth of bread mold. This is determined by inspecting the bread with a magnifying glass. The constants (control variables) are the room temperature, the age of the bread and the handling of the bread.
2. The 5 slices of bread are prepared as follows :
a. a few drops of water are placed on the 1st slice of bread and it is kept in a dark and damp place,
b. the 2nd slice of bread is kept unattended under normal room conditions,
c. the 3rd slice of bread is kept under the hot sun,
d. the 4th slice of bread is kept inside an air tight plastic bag,
e. the 5th slice of bread is kept in the refrigerator.
3. The bread slices are observed daily to see if there are any signs of mold growing. The results are recorded in the table below.
4. If there is no sign of mold growth, the box will be ticked ‘ X’. If mold growth is found, the box is ticked ‘v’.
Results
It is observed that the 1st bread slice with a few drops of water and kept in the dark space had started to grow mold the fastest. The 5th bread slice that was kept in the refrigerator took the longest for the mold to appear.
Environment |
Day 1 |
Day 2 |
Day 3 |
Day 4 |
Day 5 |
Day 6 |
Day 7 |
Day 8 |
Wet bread in dark area |
X |
Y |
Y |
Y |
Y |
Y |
Y |
Y |
Bread in room condition |
X |
X |
X |
Y |
Y |
Y |
Y |
Y |
Bread kept under the sun |
X |
X |
X |
X |
X |
Y |
Y |
Y |
Bread in airtight bag |
X |
X |
X |
X |
X |
Y |
Y |
Y |
Bread in refrigerator |
X |
X |
X |
X |
X |
X |
X |
Y |
Conclusion
The hypothesis that bread mold will grow faster in warm and damp environment is proven to be true. Mold will grow fast on bread in humid and warm conditions. Bread should be kept in dark, dry and cool places for it to last longer. Bread can also last longer if stored in the fridge or in airtight containers. Adding some small amounts of edible chemicals like acetic acid or prop-ionic acid to the bread will also help to preserve it longer.
Mold is a nuisance when it comes to storing food, but it has its usefulness too. Molds help in the decomposing process of decaying animals and plants. Penicillium is used in pharmaceutical work to produce medicine.
Also consider
What would happen if the experiment was repeated by baking the bread at high temperatures again before starting the experiment?
The experiment can be repeated using different types of food like biscuits or cooked rice.
References
Bread mold - http://ezinearticles.com/?Bread-Mold&id=405845
Bread storage to prevent spoilage - http://www.ehow.com/way_5746731_bread-storage-prevent-spoilage.html
