When we talk about exporting fresh fruit, especially in the post-harvest of cherries, time occupies the first place in the ranking of factors that affect the condition of the fruit upon reaching its destination. Although dehydration and metabolism are the two great executioners, these manifest themselves over time, putting at risk the firmness, freshness of the pedicels and the weight of the cherries. That is, the longer the exposure time of the cherries to the different environmental conditions they face throughout the post-harvest, the greater the deterioration evidenced by the fruits. Therefore, to face this challenge, it is essential to measure and manage time accurately throughout all the stages that make up the post-harvest process. How is this achieved? First, by measuring each stage (with a watch!) and then by making decisions that allow it to be reduced, especially in critical stages. We could say, as an example, that if we reduce the time by half we will obtain double the benefits.
The moisture chain: a detailed analysis
To understand how time impacts the condition of cherries, we can segment the cherry post-harvest process into six key stages: (1) harvest, (2) field collection, (3) transport from the field to the packing plant, (4) reception at the packing plant, (5) waiting for processing in the raw material chamber, and (6) sea transport. Each of these points requires a thorough analysis to identify how to improve the times of each process.
1. Harvest
Our recommendation is that a bin should be filled in no more than 30 minutes. To achieve this goal, producers must optimize their logistics, which may involve increasing the number of workers to speed up the filling of the bins. Once the bin is filled, it must be transported within the next 10 minutes to a collection center equipped with a proper humidification system. The total time, from the start of filling to arrival at the collection center, should not exceed 40 minutes. Planning is essential, since everything defined at this stage affects the efficiency of the harvest in one way or another, from the location of the collection centers to the number of tractors available to transport the bins.
2. Field collection center
The collection centre must be properly constructed, using appropriate mesh, dimensions and doors. It is crucial to correctly install a high-pressure humidification system to achieve a relative humidity higher than 90% and maintain the ambient temperature around 20°C. In addition, the pulp temperature must be maintained within these same ranges. The main objective is not only the collection or the humidification system itself, but to ensure that these elements contribute to reducing fruit dehydration by 94% (green pedicels) and to effectively control its metabolism (maintain firmness).
The length of time that the fruit remains in the collection center depends on how long it takes to gather the load and how often the trucks arrive at the field. For this reason, the collection center functions as a “lung,” allowing fruit to be accumulated based on the environmental conditions achieved. During this time, damage to the fruit is minimal. For example, it can be said that 25 hours in a humidified storage area causes the same degree of dehydration as one hour outside of it. When planning does not go as planned, the collection center becomes an effective contingency measure.
3. Transport from the field to the packing plant
Transporting cherries in refrigerated trucks is the most recommended option. Although we cannot precisely control the journey time, we can regulate the ambient temperature to prevent the pulp temperature from rising and to minimize wind damage, a common problem with flatbed trucks.
As a final recommendation, when transporting fruit with hydro, the temperature of the truck should be 5°C. In contrast, for fruit without hydro, the ambient temperature of the truck should be around 15°C. This is crucial to prevent extreme dehydration, which can be caused by a high vapor pressure deficit inside the truck. Controlling these variables will help mitigate the damage caused by the impact of time on the cherry during transport to the processing and packing plant.
4. Reception at processing center and packaging
Each new season, exporting companies make an estimate of the quantity of fruit that will arrive at the packing plants and the estimated dates of reception. However, it is not possible to project or control the time at which the fruit will arrive at the processing plant. This is a major problem that causes bottlenecks in the reception area of the packing plants - prior to hydrocooling - on certain dates and times. Trucks in a long line waiting to be unloaded and large quantities of bins loaded with cherries waiting their turn to be entered into the hydrocooler are a common sight at certain times of the season. To ensure that these "bottlenecks" do not mean a further deterioration in the condition of the fruit, the implementation of an efficient humidification system in the reception area will be the best strategy, which will allow the wait to be as little harmful as possible for the cherry. Thanks to these measures, although we cannot control the weather, we have managed to mitigate the damage that the weather causes to the cherry, managing to reduce dehydration in this area by up to 80%.
5. Raw material chamber (waiting for processing)
Each plant has a limited fruit processing capacity per hour and, therefore, during peak periods of fruit arrival at the plants, the fruit is subjected to waiting for variable durations, which occur inside refrigerated chambers and can extend from a few hours to several days. Naturally, the longer the waiting time, the greater the dehydration experienced by the cherries. Until the third day, the fruit is protected from dehydration by the water remaining from its passage through the hydrocooler, so if the wait is less than this period, dehydration will be minimal. However, from the third day onwards a dehydration process begins which will reach, on average, 2.6% after 8 days. If it is not possible to reduce the time that the cherries remain in the raw material chambers awaiting processing, the implementation of humidification systems is an essential measure to eliminate dehydration in 80%.
6. Maritime transport
In maritime transport, it is essential to opt for faster routes, such as the Asia Express or Cherry Express services, which reduce transit time by 10 days. This time saving is a significant achievement for the cherry industry and contributes to preserving the quality of the product.
As we can see, in the post-harvest of cherries, time is a determining factor that requires meticulous attention. While we cannot control every aspect of the process, we can optimize those times that are within our control and employ technologies such as our humidification systems to mitigate damage. The key is efficiency and planning, ensuring that each stage of the post-harvest chain is handled precisely to preserve cherry quality and maximize profits.
