Transporting Perishable Commodities
After harvesting, fruits and vegetables continue to "live and breathe" consuming oxygen and producing carbon dioxide. This respiration means a loss of sweetness and a change in texture in most produce, however, the major effect of respiration is heat generation, which speeds up all other forms of deterioration. Controlling the following can reduce deterioration of perishables:
Cooling
Cooling is the simplest and most powerful technique for minimizing deterioration. Cooling of fresh produce should begin as quickly as possible after harvest. Reefer containers should not be used to reduce the temperature of produce they are designed to maintain, rather than to lower the temperature of the cargo. Please see Compatibility of Fresh Produce for an indication of recommended temperatures and humidities for products commonly transported by reefer.
Temperature
Other factors such as the temperature of the air which is delivered from the reefer unit either into the storage facility or the container and the temperature of the air leaving the interior of the cold store or container before being returned to the reefer unit must also be controlled.
Humidity
The relative humidity of the air around a product is important in determining their storage conditions. A Low relative humidity will cause desiccation (water loss) and weight loss of the product and in certain circumstances even packaging. A high relative humidity can also produce undesirable affects in the product such as encouraging the growth of bacteria and mold as well as producing physiological disorders.
Weight Loss
Weight loss both during storage and transportation can be prevented by maintaining the correct temperature and humidity.
Air Circulation
If the air cannot circulate correctly in the cold store or container then problems can arise affecting the shelf life of the product. Poor circulation can affect the commodity’s temperature, relative humidity and weight loss. If a cargo is "hot" ie it has not been adequately pre-cooled it is essential that there is an adequate air flow to cool the produce as quickly as possible.