How to Grow Mold Quickly on Bread

Updated February 21, 2017

Mold growth can ruin a good loaf of bread but also serves as a fun and worthwhile science experiment. Left for prolonged periods of time, bread will naturally develop mould, a fungus that develops from spores collected by dust in the air, depleting the bread of its nutrients and creating a very unpleasant taste. If you want to study the growth and effects of mould spores on bread, you can conduct a home experiment to accelerate the mould growth.

Select a bread with a high water content. Mold grows fastest in moist environments, so you should first consider your bread type. Breads such as Boston brown bread, oat bran bread and plain white bread have some of the highest water contents, according to Phyllis Stumbo of the University of Iowa nutrition staff.

Collect dust on a cotton swab. You can slide the swab along a dusty shelf, floor, television set or any other surface with a thick coating of dust. Since dust contains the spores from which mould grows, you will want to collect as much dust as possible.

Rub the cotton swab over the entire surface of your bread slice, coating it with the dust. The moisture from the bread combined with the spores contained in the dust create an ideal breeding ground for mould. You can also drop a few sprinkles of water on the bread slice.

Seal your bread in an airtight environment to lock in the dust. You can place it inside of an airtight sandwich bag or wrap it in firmly in cling film.

Place your bread in a warm, dark environment to accelerate the growth process. For example, the website Science Fair Adventure recommends placing the bread in an old milk carton (preferably one with traces of milk still left behind) and sealing the lid. Leave the bread alone for approximately 24 to 48 hours and remove.


Always wear protective gloves when working with dust and mould.

Things You'll Need

  • Protective gloves
  • 1 slice of bread
  • Cotton swab
  • Cling film
  • Used milk carton
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