|Growing vegetables can be attacked by plant pathogens which damage the tissues. An example is potato blight, a fungal disease which can ruin whole crops. Plants fight back by:|
- having thick skins to repel microbial invaders
- producing anti-microbial compounds
All vegetables can be spoiled during harvesting, processing, transport and storage. Spoilage is more likely if the crop is damaged as this enables microbes to enter the tissues. A broken skin releases nutrients which support microbial growth. The vegetable may become spongy and soft, as microbial damage to the plant cell walls releases the watery contents. Vegetables have a higher pH than fruit, though they are still slightly acidic. This encourages bacterial as well as fungal growth around one third of total microbial spoilage of vegetables is due to bacteria.
Spoilage can be prevented by careful handling and transport. Fresh vegetables can have a good storage life if kept in the correct conditions. Refrigeration slows down microbial growth; control of humidity is also important as condensation will encourage bacterial growth and too dry an atmosphere will lead to wilting of the produce. Packaging can regulate the amount of oxygen and water reaching the plant and the microbes growing on it.
Any treatment of vegetables will affect the type of microbes present and their rate of growth.