CATsystem®, the new automatic control system for postharvest treatments

According to the most common procedure, after being harvested, when citrus fruits arrive at the packinghouse, a fungicide treatment is immediately applied to control rot.

This treatment is applied in the vast majority of cases by drenching the pallets with fruit. In the current context of water scarcity and absolute respect for the environment, this treatment solution must be reused to reduce water and chemical consumption and to avoid the generation of wastewater. To enable this reuse, Citrosol launched the Zero Waste® system in 2010, which replenishes the solution taken by each pallet, filters and disinfects it, preventing the reduction of fungicide due to dilution and the accumulation of sludge and fungal spores that could reinfect the fruit.

The Zero Waste® system was a major technological advance in the utilization of the treatment solution. However, it is not sufficient to ensure a constant concentration of all active ingredients in the solution throughout the entire time due to the occurrence of industrial alterations. These alterations are events or factors that occur in the industrial environment of a packinghouse and can randomly modify the concentrations of these active ingredients, both above and below their optimal value.

Among the main alterations are human errors, application system incidents, degradation by matrix effect (caused by the wide variety of compounds that end up in the solution from field treatments), and absorption by materials in contact with the solution, the fruit itself depending on its condition, or the solids in suspension (soil and field sludge). These alterations can be very diverse, cumulative, changing, and unpredictable, and therefore impossible to successfully control in real-time with only human supervision.

During postharvest, insufficient fungicide concentration can increase the occurrence of rot (lower treatment efficacy, resistance generation from working with sublethal doses, lower sporulation control, etc.), while excess can exceed legally established Maximum Residue Limits or the even more stringent levels imposed by distributors.

Thanks to CATsystem®, the first Automatic Treatment Control System (Figure 1), these mentioned alterations can be countered automatically (without human intervention), on-site, and in real-time, to maintain constant concentrations of fungicides, disinfectants, and food additives in the solutions within a defined range of values.

Figure 1. CATsystem® first Automatic Control System for postharvest fungicide treatments

The CATsystem® takes samples from the treatment solution tank, analyzes them to measure the actual concentration of fungicides, disinfectants, and additives, such as imazalil, pyrimethanil, ortho-phenylphenol, thiabendazole, fludioxonil, azoxystrobin, triclopyr, potassium sorbate, peracetic acid, etc., and makes necessary corrections at all times based on the results obtained automatically, to always ensure a constant concentration. Below, in Figure 2, we can see an excerpt from the records of an industrial pilot at a real client.

Figure 2. Analysis results, deviations (%), and corrections. [IMZ]target = 450 ppm, [PYR]target = 640 ppm. Tolerance in deviation from target: ±20%

With CATsystem®, Citrosol is set to revolutionize the way postharvest treatments are applied, providing automation and real-time control of the treatment, detecting both malfunctioning of the doser and human errors of the operators; taking rot control to a higher level; increasing the customer's economic savings by reducing waste and claims, and last but not least, offering greater peace of mind to the customer.