Is It Safe to Eat Moldy Bread?

Medically Reviewed on 8/16/2022
Moldy Bread
Eating moldy bread can cause various side effects and negative health problems.

No, it is not safe to eat moldy bread. Researchers suggest that eating moldy bread can cause allergic responses or respiratory issues. A certain variety of molds produces dangerous mycotoxins that can make you sick or infect you. Bacteria can develop with mold, making it much riskier to ingest.

What is mold?

Mold is a fungus that grows in warm, damp environments. Mold spores travel in the air all the time, and when one hits the surface of bread or any perishable food, it releases chemicals that cause the item to decay. The decaying bread provides nutrition and promotes mold development, changing from white to greyish or black.

Is it safe to eat moldy bread after cutting off the mold?

If you are inclined to separate the visible mold from the remainder of the bread, keep in mind that mold spores and roots are small and may have already infiltrated the entire loaf.

There is no way of knowing whether the spores are influencing the remainder of the bread. Therefore, clipping the mold of the loaf is not a good idea.

Mold roots spread toxins called mycotoxins (lethal chemicals to humans) into the bread as they grow, and some types of hazardous bacteria may accompany them.

The visible sections of mold, known as sporangia, release massive amounts of spores, which settle and spread on the other slices in the bag.

4 causes of mold growth on bread

  1. Moisture
    • Mold requires water for various chemical activities at the cellular level.
    • Thus, the presence of water promotes the formation of bread mold.
  2. Bread becomes food
    • Mold is a fungus that requires the energy of other living species to flourish because it does not make its food as plants do.
    • The components in bread provide food for the formation of bread molds. Bread is porous, making it ideal for the growth of fungus.
    • Researchers suggested that anything that contains carbon can provide the necessary nutrition for the development and growth of the mold.
  3. Temperature
    • Warm temperatures promote optimal mold development because enzymes or proteins that govern chemical reactions function more efficiently when it is warm.
    • Researchers suggested that the perfect temperature for molds to develop and thrive is about 80.06 °F.
    • Refrigerating bread slows down mold formation and freezing bread stops mold growth entirely.
  4. Spores
    • Mold spores are present everywhere in the air around you.
    • When these spores land on the bread and under suitable conditions, the spores consume all the nutrients from the bread and start to develop.


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How can moldy bread be prevented?

To protect the bread from mold, store it in the right place at a suitable temperature, light, and moisture levels. Preservatives that inhibit moldy growth are added during the preparation process of bread.


  • The environment in which bread is stored has the greatest influence on mold formation on bread.
  • Bread should be stored in a cool, dry area. It could be stored in the refrigerator, but it will quickly dry up and turn stale.
  • Store your bread in a breadbox or linen bag away from heat and moisture.
  • The bread should be ventilated. However, it should not be placed in a humid, moist place.
  • You may freeze bread to make it last longer. To make this a handier option, slice your bread and freeze it at 0 °F with wax or parchment paper between slices.
  • Before freezing your bread, place it in a freezer bag with as little air as possible trapped within.
  • The bread can be kept in the freezer for about six months.
  • Do not keep it in the freezer door.
  • To use the frozen bread, thaw it at room temperature for an hour.


  • Preservatives increase the shelf life of the bread, so commercial bread has way more shelf life than bread with no preservatives.
  • Homemade bread contains few to no preservatives, so mold can colonize and develop on it more quickly.
  • You may add preservatives to your bread when you make it at home.
  • Garlic, honey, cinnamon, and ginger are among flavoring compounds that work as natural preservatives.
  • Ascorbic acid or lecithin could be added.
  • The sourdough starter could be used as a yeast culture because it contains a combination of yeast and lactobacilli. The lactic acid generated by the lactobacilli lowers the pH of the bread, reducing the ability of molds to colonize.

What happens if you eat a slice of moldy bread?

Bread with obvious stains or mold should not be consumed. Eating moldy bread can cause various side effects, such as:

  • Food poisoning
  • Allergic reactions
    • When you consume moldy bread or inhale the spores of the mold, you may develop allergic reactions.
    • You may develop breathing issues, such as asthma attacks, coughing, and sneezing.
    • You must be cautious if you develop wheezing, lung infections, or any other respiratory issue.
    • People with a weakened immune system may even develop life-threatening complications.

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Medically Reviewed on 8/16/2022
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