What preservatives keep bread from molding?

Updated April 17, 2017

Bread is high in sugars and moisture, therefore it develops mould quickly. Most preservatives used for bread occur naturally, however some people react negatively to certain preservatives, just as some react to certain foods. Preservatives do not kill all bacteria in food, they merely inhibit the growth of mould and toxins. Without preservatives, many tons of bread and other foods would be wasted each year.


Mouldy bread can produce mycotoxins that can make you sick, so preservatives are often used to inhibit mould growth. Mycotoxins occur mostly in grains and nuts, but they can also occur on celery, grape juice and apples. Approximately 25 per cent of world crops are affected by mycotoxins.

Sorbic Acid

Sorbic acid occurs naturally in rowanberries and mountain ash berries. It is the active ingredient in sorbic acid and potassium sorbate, both of which are used to preserve tortillas and other unleavened breads. Sometimes it is sprayed on the surface of the food to inhibit mould growth. Sorbic acid inhibits yeast fermentation so it is not used in yeast-leavened breads.

Sodium Benzoate

Sodium benzoate is the sodium salt of benzoic acid and it exists naturally in cranberries, prunes, greengage plums, cinnamon, cloves and apples. It also occurs in vinegar, which is often used in preservative-free breads. Preserves, pickles, sauces and salad dressings are mostly preserved with sodium benzoate.

Calcium Propionate

Calcium propionate inhibits the mucoid variant of Bacillus subtilis and mould development in bread. Bacillus subtilis has been linked to outbreaks of food poisoning. Calcium propionate also adds extra calcium to the bread. Calcium propionate works well in yeasted bread, as it does not inhibit yeast fermentation.


All preservatives mentioned here are approved by the FDA, and are considered safe for human consumption if used in the correct amounts. According to the Food Intolerance Network, a number of people report negative reactions to calcium propionate. Reactions include eczema, nasal congestion, irritability and inattention and it has even been linked to ADD in children.

Natural Alternatives

Add a teaspoon of honey to your bread while you mix it, as this helps to inhibit the growth of mould. Along with natural preservatives such as vinegar and honey, there are other ways to preserve your fresh bread. Start by letting it cool completely before storing it in a bread crock. Freezing fresh, unpreserved bread helps keep it fresh longer.

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About the Author

Kerry Voronoff has been writing for the Web since 2002 and has had her work published by Voronoff has studied professional writing at Victoria University of Technology in Melbourne, Australia, and holds an Associate of Science in computer information systems from City College in San Francisco.