Growing the Wrong Kind of Green

Scripture: Genesis 39-41

Learning Objectives:

  • Students will review how Joseph helped the Egyptians store grain for the years of famine.
  • Students will experiment with moisture, temperature and bread to explore the conditions under which mold grows.
  • Students will learn the signs of mold and how to prevent it so that bread stays fresher for longer.

Guiding Questions:

What causes mold to grow on food?

What prevents mold from growing on food?

How do we test food for mold?

Materials: Bread, plastic zipper bags, spray bottle of water

Review the story of Joseph helping the Egyptians store grain for Egypt. Ask students how they think the grain would have been stored. What conditions would keep the grain healthy for a long period of time? Ask if they have ever seen moldy bread or cheese before. Explain that mold is a type of fungus that can cause illness and stomach problems. Show them pictures of different kinds of fungus including different colors, molds and mushrooms.

Ask students where they have seen mold and under what conditions. Mold likes warm moist places like humid forests and even uncleaned bathrooms! Yuck! Bread is more likely to mold if moisture gets to it, hands aren’t properly washed before touching the loaf, and if it is stored in a warmer environment.

Let students experiment with conditions for mold growth. You will need a plastic bag and piece of bread for your variable and control group. Choose one control by sealing a slice in a bag and placing it in a room temperature environment. Then try to make mold grow on another piece by spraying it lightly with water (careful not to drench sweeter breads as they will dissolve), trying to get mold spores by rubbing the bread with leaves or a dirty window sill, setting it in sunlight, etc. Seal it in a plastic bag. Emphasize to students that they are not to ever reopen the bag once it is sealed, especially when mold starts to grow.

When the experiment is finished they are to throw it away without touching or smelling it. Explain that this is importance for health reasons and that mold spores can spread. This experiment takes 6-14 days. Observe it each day. If you will not see students again or for several days, students can take a control and variable bag of bread with them to continue the experiment at home. Encourage them to keep a daily journal of observations and report back to the class at the following session so that they can compare results. Another option would be to do one as a class and students can observe the results when they return.

Review how to best prevent moldy bread:
1. Wash hands thoroughly before touching it
2. Keep the container well sealed without letting air get to it
3. Keep at cooler temperatures
4. Do not let moisture get to it

Review how to check for mold:
1. Look for unusual colors such as black, green, white, or pink
2. Mold is often fuzzy
3. Smell the bread for freshness. It should smell appetizing. If you think it might be moldy do not inhale too deeply to prevent inhaling spores.
4. If in doubt, throw it out! Do not taste-test it.

Additional Questions:

  • What types of fungus do people actually eat? (Bleu cheese, mushrooms)
  • True or False: If only one slice of bread in a loaf has mold, then it is safe to throw out the slice and eat the other part of the loaf. Answer: False! Mold spores spread and can be microscopic. There may be more fungus all over the loaf, but the mold colonies have not yet grown large enough to see with the human eye.

Supplemental Activities:

  • Students can research types of foods that typically mold faster. Ask what causes them to grow fungus more quickly and the best way to resolve it.
  • Students can create a written and/or illustrated “Pantry Plan” for their home that sets rules for how to handle food in a pantry so that it lasts longer and does not become contaminated. It can also include what types of foods belong in the pantry vs. what should go in the fridge.

Written by: Savannah Negas

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