Microbes and food 4. Food spoilers
4.3 Fruit and vegetables
Mouldy strawberry photo
Picture 4.3a A strawberry is a good host for mould.


Fruit have a high water content. This, along with their acidity, can lead to yeast and mould spoilage. Many of the fungi are specific to particular fruits. For example, strawberries are affected by the grey mould Botrytis. Careful handling and storage help to prevent spoilage. Some fruit are treated with biocides.


These are dry and tend to be attacked by moulds. This leads to discolouration, heating, musty smells and general decay. Spoilage can be controlled by dry storage conditions.

Aspergillus nidulens photo
Picture 4.3b Aspergillus nidulens, a fungus, growing on maize.

Nuts, seeds & pulses

These are rich in oils and are spoiled by fat-loving moulds which can be kept in check by storage in dry, cool conditions.


Vegetables are less acid than fruit and suffer bacterial spoilage as well as playing host to moulds. Microbes often enter through bruises or other damage. The tissues soften due to microbial enzymes breaking down the pectin holding the cell walls up. Eventually the vegetables rot away completely. Suitable storage conditions are the key to prolonging shelf life. Surface dryness will stop mould growth.