In previous posts we have addressed the topic of post-harvest as a process involving multiple stages, each with distinct characteristics, which occur in diverse spaces where cherries are exposed to different environmental conditions. Consequently, it is crucial to implement various methods to minimize cherry dehydration and achieve this goal.
On this occasion, we will delve into the harvest, understood as the period that elapses from when the fruit is removed from the tree until it is transported to a collection center. It is in this first stage of post-harvest where the cherry is exposed to the highest levels of dehydration per unit of time, so it is essential to implement management that allows the best possible conservation of the quality of the fruit, related both to the mitigation of the effects of environmental conditions on the cherry and to the reduction of times.
The first hours of the day are crucial for the harvest, since during this period the vapor pressure deficit is very close to zero and, therefore, the dehydration to which the fruit is exposed is minimal. To take advantage of this natural condition, the recommendation is to start the harvest as early as possible, as soon as natural light allows. The time will depend on the location of the farm, however, it should generally begin at 6 in the morning.
As the hours pass, the solar radiation incident on the orchard increases, raising the air temperature and decreasing the relative humidity. In order to minimize the exposure of the fruit to the high levels of dehydration to which it is exposed due to these conditions, the bins should be covered with a sponge soaked in water, which should remain in place from the arrival of the first harvest box to the bin. It is important to ensure that the sponge maintains an adequate amount of water, since dry sponges will have the opposite effect on the fruit. As a complement to this management, shading the area where the bin is located will allow the sponge to remain with sufficient humidity for the necessary time and without significantly increasing its temperature. This is possible by using Raschel mesh covers as shown in figure 1.
Additionally, it is essential to minimize the exposure time at this stage, so the bin should be filled in no more than 40 minutes. Once full, it should be removed within the next 5 minutes to be taken to a collection center equipped with a humidification system. There, maintaining a relative humidity of 90%, the cherry can safely await its transfer to the processing plant, in an environment in which it will be protected from dehydration.
In order to optimize the work of the harvesters, it is necessary to ensure that the bins are distributed along the row so that the time taken to bring the harvested fruit to the bin is as short as possible. In this way, the harvester will spend more time harvesting and less time walking to and from the bin.
Effective supervision of harvesting work must include the evaluation of both the fruit that reaches the bin and the fruit that does not reach it, that is, the fruit that remains on the tree and that which is lost during harvest (that falls to the ground). For this reason, for effective control of harvesting work, it is recommended that the crew be made up of one supervisor for every 10 harvesters. A higher proportion of harvesters will make it difficult for the supervisor to properly inspect the work.
In conclusion, cherry harvesting is a critical stage in the post-harvest process in which various methods must be implemented to minimize fruit dehydration. Management focused on starting early in the morning, reducing times, having contingency measures in case of eventualities, reducing the fruit's exposure to dehydration and controlling the pulp temperature will allow minimizing cherry dehydration, prolonging post-harvest life and allowing the fruit to reach its destination in optimal condition.
