Post-harvest is the process that begins from the moment the cherry is removed from the plant and continues until it reaches the final consumer. For export cherries, several stages occur during this journey during which it is common to encounter practices and handling that have now become commonplace, but which, however, often lack clear foundations and few know the reason behind them or their real effect on the cherry.
Every management action must be based on data, evaluations and reasons that justify its implementation. From decisions related to harvest schedule, the use of covers on storage bins, the choice of truck type for transport, to specific actions such as wetting the floor in cold storage rooms, all must be supported by reasons based on measurements and evaluations of the variables involved.
Let's take harvesting time as an example. For this task, the time that minimizes the fruit's exposure to dehydration and avoids high temperatures in the pulp must be chosen, therefore, the earlier the harvest begins, the better the results will be. However, the end time of the harvest can vary considerably, since each orchard has its own justifications and realities. It is advisable to carry out specific evaluations in each orchard to determine the optimal harvest times based on the vapor pressure deficit (VPD) as an indicator of the dehydrating capacity of the environment. A study that we carried out with our R&D team in the 2021-2022 season in a cherry orchard in the town of El Abra, O'Higgins Region (Chile), allowed us to identify that the highest levels of VPD were observed between 12:30 and 20:00 hours (Figure 1). In this range, the VPD exceeded 2 kPa, identifying a peak close to 3 kPa between 3:00 p.m. and 6:00 p.m. This should be a fundamental assessment in orchards when defining the end time of the harvest.
Figure 1. Evolution of vapor pressure deficit (VPD) throughout the day in a cherry orchard during harvest season.
Another example is the use of meshes Raschel, commonly used as shade nets. It is important to understand the effect that these nets have on the fruit underneath them. However, there are different percentages of shading in the nets, which will affect the fruit differently. Together with our R&D team, we carried out a test that evaluated the effect of the net Raschel in a field fruit collection center on the observed temperature and relative humidity. The results (Table 1) revealed that, when in full sun there was 32°C and 23% RH, under a collection center covered with mesh Raschel With 80% shading, the air temperature decreased to 29°C and the relative humidity increased to 29%. By using a double layer of this mesh, the temperature decrease was greater, reaching 26°C and increasing the relative humidity to 45%. By adding to this the implementation of a humidification system, the air temperature decreased to 21°C and the relative humidity was raised to 74%.
| Deck | Air temperature | Relative humidity |
| Full sun | 31.7 °C | 23.4 % |
| Mesh Raschel 80% | 28.9 °C | 29.4 % |
| Mesh Raschel 80% double | 26.3 °C | 45.1 % |
| Mesh Raschel 80% double +Humidification | 20.6 °C | 74.2 % |
As a third example we can mention the use of wet sponges on bins during truck transport from the field to the processing plant. Although the wet sponge is highly effective in protecting the fruit from dehydration and temperature increase while inside bins in the orchard inter-row, its impact during truck transport is no longer significant if a suitable truck is used. In this case, it is sufficient to ensure that transport is carried out in a refrigerated truck and that the temperature is adjusted to achieve a minimum vapour pressure deficit.
These examples illustrate the need to carry out measurements and evaluations to understand the real effect of the practices and handling carried out during post-harvest in cherries. We can conclude, based on the above, that each action carried out during the post-harvest process must be supported by concrete data that allow informed decisions to be made, always for the benefit of the fruit.
