Orange Cooling and Storage

Oranges should be stored in well-ventilated cartons to allow for good airflow and thus also thorough, uniform cooling. It is important to avoid over-filling containers as this could not only interfere with airflow but also result in physical damage to the fruit. Room cooling involves placing the oranges in a refrigerated room and allowing them to gradually acclimate to ambient temperatures. For this method to be effective it is important that the oranges be packed in cartons with good airflow. Room cooling may not be ideal in some circumstances because cooling is more gradual and takes a long time. Instead the oranges may be subjected to forced-air cooling as an alternate method. This involves placing the oranges in a cooler as with room cooling but also arranging them around a fan that will pull cold air through the oranges, thereby greatly increasing the speed and efficacy of cooling. Hydrocooling involves rapidly submerging the oranges in near freezing water as a way to very quickly lower their temperature. This is a very effective way of removing field heat and preparing the oranges for more long-term cooling such as room cooling or forced-air cooling. It is not economical to fully chill oranges using hydrocooling because the cooling load is high after the initial field temperatures have been removed. Oranges should be stored at about 4°C to 9°C. Warmer temperatures will result in more rapid loss of quality

while prolonged exposure to temperatures below 4°C may result in freeze damage. The optimum temperature within that range of 4°C to 9°C will vary slightly depending on the initial condition of the oranges as well as their particular cultivar. Oranges thrive at a relative humidity of about 90% – 95%. Lower relative humidity may result in moisture loss while higher relative humidity may elevate the risk of certain fungal attacks. Under ideal cooling and storage conditions oranges have a shelf life of up to 2-3 months.