Chilling injury
Also known as: chill damage, cold injury
Short definitionPermanent tissue damage in fruit and vegetables from warm climates when they wait in too much cold, even though they do not freeze. Bananas cannot take less than 13 °C, cucumbers less than 10 °C.
Putting everything in a greengrocer’s store into a single room at 2 °C is the best-known route to this damage. Carrots and apples wait for months at zero; bananas spoil below 13 °C, mature green tomatoes below 12–13 °C, aubergines and cucumbers below 10 °C and peppers below 7 °C. The skin pits and darkens, and the fruit never ripens. The damage is not noticed in the room; it shows within a day or two once the product warms up on the shelf. That is when the complaint arrives.
A customer who will store mixed produce is offered at least two separate temperature zones: one at 0–2 °C, the other at 8–12 °C. In the warmer zone the supply air matters as much as the set point. If the room is set to 14 °C, the air leaving the evaporator must not be colder than 13 °C. A large-surface evaporator, a small temperature difference and stepped capacity control achieve this. The length of exposure matters as much as the degree of cold; a few hours leave no mark on most produce.