Extreme climatic conditions reduce yields and increase postharvest losses. They also trigger biophysical reactions in plants in response to environmental stresses. These reactions include concentrating chemical compounds that are harmful to animal and human health. Despite a plant’s various protective responses, in prolonged unfavourable conditions stress can overwhelm its ability to thrive, and can weaken the plant further, leading to increased disease susceptibility. In such cases, either the plant itself or invading microbes can produce speci!c chemical compounds at levels toxic to human health.