Select four slices of bread preferably from a loaf without preservatives (this will speed your mold growth.) Give each piece the following treatment and then place the slices into a “treatment-labeled” Ziploc bag. Store the bags in a warm, dark place for incubation
Wipe an unwashed hand (pretend you are smearing on mayonnaise with your entire hand) on both sides of the slice.
Place it into a Ziploc bag.
Lick one piece on both sides with your tongue.
Wipe one piece on both sides on the floor.
WASH YOUR HANDS.
Place one slice onto a paper towel.
Moisten the slice with water from a mister bottle.
Observe the bread for microorganism growth every other day for the next week. (This may take longer if you are using bread that contains growth inhibitors or preservatives.)
Ask the students to record their observations.
At the end of 2 weeks review the results and make some class conclusions.