By Ari Goren
Israel: New pre-cooling system for cherries
The low humidity and the high air temperature are the main parameter of damaging the fruit quality. The new system enables the grower to cool the fruit while it is still in the orchard.
The majority of the cherry production in Israel is concentrated in the Golan Heights. The harvesting season in this area starts at the beginning of April, till the end of July and is characterized by high temperatures and low humidity. Picking is done by hand and the fruit is picked into plastic crates. The fruit, then, waits a long period of time in the orchard until the crates are collected and taken into the packing house where the fruit is finally refrigerated at a temperature of 5 degrees Celsius. At this interval every two pallets of fruit crates are taken into a special "rapid-pre-cooling" chamber. This process involves a hydro cooler, which sprays cold water on the pallets and takes half an hour. In the second stage, when the fruit becomes colder, it is returned to the regular cold storage and held there at the desired temperature.
"Our system is based on placing the fruit into a mobile cooling chamber immediately after being picked and while still in the orchard."
This mobile cooling chamber is towed by a farm vehicle and enables the picked fruit to immediately reach the desired holding temperature and humidity conditions, thus controlling the quality and freshness of the fruit by special recorders.
At the front of the chamber a moist "mattress" is installed, which is moisturised with constantly running cold water from a tank using an electric pump. Two suction fans, installed in the ceiling of the carrier at its rear end, cause the air to flow through the mattress towards the area where the fruit is situated.
How it works
The system was designed and planned at the Institute of Agricultural Engineering in Israel and the carriage was built at "Egoz", a company based at Kibbutz Gezer. The construction was closely followed by engineers from the Institute of Agricultural Engineering. The carriage is reticulated by sensors which measure the temperature and relative humidity and are connected to a data recorder.
Beni Bar Yehuda, from Egos explains, "as from the data results, we can strongly recommend to use the system because from the moment the carriage doors were closed, the relative humidity rose to 90% and the air temperature fell to 19 degrees Celsius"
It should be emphasized that the outdoor conditions at the same time were 28 degrees Celsius and 35% relative humidity. The comparison of fruit quality after the harvest, between the carriage-chilled fruit to the other fruit was strictly checked and showed very clearly that the fruit which was transported via the rapid cooling carriage was of a higher quality and reserved its fresh look and green stem.
During the harvesting season, the carriage was fitted with relative humidity and temperature sensors, which were connected to a data recorder.
The conditions in the carriage and in the orchard and the temperature of the fruit were verified and the results show that it is possible to raise the humidity level up to 85% - 90% and the temperature up to 18 degrees Celsius.
It is fully recommended to activate the system about half an hour before loading the fruit and thus enabling the carriage interior to reach the optimal conditions.
"We do believe, so far, that our rapid pre cooling system gives the Israeli cherry growers the best solution for keeping the fruit in the best possible conditions while harvesting during extreme high temperature and law relative humidity".
For more information:
Beni Bar Yehuda
EGOS
Tel: +972-54-2573300
benibar@betzera.org.il