
Temperature management apples
An optimal temperature is mostly the first requirement to maintain a good quality of horticultural produce after harvest. Refrigeration is an effective method of preserving the quality of apples. Cooler temperatures extend the storage life by, among other things, reducing respiration, water loss, colour change, and decay. The apples should however not be stored below their critical temperature. This would result in risks on various quality problems such as weakened tissue leading to discoloration and increased risk of decay. The optimum temperature varies per commodity and cultivar and should be controlled throughout the whole fresh supply chain.

Optimal storage temperature
Attention points before the apples enter the storage room

Apples should be cooled rapidly after harvest. Ensure that the product ends up as soon as possible in a refrigerated area after harvest. Optimally within a few hours after harvest, and never longer than 24 hours. Never leave the product outside with thinking the heat will pull out during the colder night. The temperature difference between fruit and outside temperature is mostly not big enough. Moreover, there is outside often not enough air circulation for an effective cooling of the apples in the middle of the stack.
The storage room should be pre-cooled before the first apples enter. In this way, more refrigeration capacity is available to cool down the apples when room loading begins. The setpoint for the air temperature during room loading varies per apple variety, harvest maturity and intended storage technology (Refrigerated Air or Controlled Air). A maturity and quality check of the apples is highly recommended to refine decisions about temperature management.
Factors determining optimal storage temperature
Heat sources in a storage room
Temperature sensors in a storage room
-
Control sensor. Photo by WFBR Control sensor
The storage room contains a number of temperature sensors. The most important one is the control sensor that measures the air temperature at a fixed position. This sensor is commonly placed in the air flow on the suction side of the evaporator. It is used to regulate the on/off cycling of the cooling. -
Product sensor. Photo by WFBR Product sensor
The use of product sensors (with probe inside the apple) are strongly advised at least at the coldest position and at the warmest position in the room. There are always some differences in product temperatures in the cold store. The warmest place of the storage room is mostly underneath the cooling system. While the coolest place is along the air flow towards the opposite side of the room. -
Handheld sensor. Photo by WFBR Handheld sensor
A handheld thermometer must be available. This should be used for routine product temperature control. In rooms under Controlled Atmosphere (CA) conditions this can be done via the control window. In this case, the safety instructions must be known and followed.
Did you know?
Related technologies and daily practices
Are you planning to do other activities with apples?
Handling apples
Fruit, vegetables and flowers are living and sensitive products. When working with fresh products like apples, it is essential to realise the importance of handling products with care. This prevents food and quality losses and profit losses.
Packing and stacking apples
Apples are packed in all types of packaging. Crates, cartons, trays, bags and punnets are convenient containers for handling, transport and marketing. Careful packing is important when working with fresh produce, to avoid damages. The packaging is designed to protect the produce from mechanical damage, but is only effective when used correctly. When stacking the packages on a pallet, the risk of falling should be minimized. It must be done in such a way the packages provide each other stability. Completed pallets should be strapped well so that the contents cannot shift or fall.
Temperature management apples
An optimal temperature is mostly the first requirement to maintain a good quality of horticultural produce after harvest. Refrigeration is an effective method of preserving the quality of apples. Cooler temperatures extend the storage life by, among other things, reducing respiration, water loss, colour change, and decay. The apples should however not be stored below their critical temperature. This would result in risks on various quality problems such as weakened tissue leading to discoloration and increased risk of decay. The optimum temperature varies per commodity and cultivar and should be controlled throughout the whole fresh supply chain.
Apple disorders and diseases
Good quality products are free from diseases and disorders! Customers will not buy apples with rots or with damaged skin. But also fruit that looks good on the outside but is brown or soft inside will not lead to happy customers. There are dozens of different diseases and disorders and these are not always easy to recognize. However, a good diagnosis is important. By recognizing the symptoms of a disease or disorder, it can be linked to the cause. If you know the cause, you know what measures can be taken to prevent the disease or disorder in the future.