High temperature injury - if fresh produce is exposed to high temperatures caused by solar radiation, it will deteriorate rapidly. Produce left in the sun after harvest may reach temperatures as high as 50 degrees Celsius. It will achieve a high rate of respiration and, if packed and transported without cooling or adequate ventilation, will become unusable. Long exposure to tropical sun will cause severe water loss from thin-skinned root crops such as carrots and turnips and from leafy vegetables. Diseases and pests .
Diseases caused by fungi and bacteria commonly result in losses of fresh produce.
Virus diseases, which can cause severe losses in growing crops, are not a serious post-harvest problem. Insect pests that are mainly responsible for wastage in cereals and grain legumes are rarely a cause of post-harvest loss in fresh produce. Where they do appear, they are often locally serious, e.g. the potato tuber moth. Losses from post-harvest disease in fresh produce fall into two main categories. Loss in quantity, the more serious, occurs where deep penetration of decay makes the infected produce unusable.