In agriculture, and in many other areas, we have always had the need to classify, segregate or order what we produce according to calibers, sizes, shapes, colors, defects, etc., criteria that define the use and destination of what is produced, and this is becoming increasingly important as a kind of filter to reach certain markets, which are increasingly demanding, and which beyond satisfying a need seek to live an experience.

The story of fruit graders is, in essence, the story of our struggle and need to achieve efficiency and consistent quality in the fruit and vegetable industry. From the basics to the most disruptive innovations, this journey began in the simplest way… manual inspection. Fruit sorters would take each piece individually and, after a purely sensory, visual, and tactile inspection, however well-trained they were, would determine, with their inherent bias, which fruit met export standards and which did not qualify for shipping. And among those that did qualify for export, and based on a very personal assessment of aesthetic defects, our employees would determine the category to which each piece of fruit that passed through their hands belonged. While this work had common criteria, it remained subjective and very slow. Each person has their own judgment, and their analytical capacity is subject to the time they dedicate to the sorting activity during their workday. It's not the same to sort first thing in the morning as it is after eight continuous hours of work, much less during the day than at night.

Thus, beyond the lack of objectivity, what led us to "mechanize" the process was the need for speed and precision. The increasing volume of fruit no longer allowed for exhaustive manual inspection; the evolution from small plots to large planted areas, and therefore the increasing volumes that required many people for sorting, were the driving forces that marked the beginning of post-harvest mechanization.

This is how we witnessed the emergence of tilting roller classifiers, rotary screen classifiers, perforated belt classifiers, and so on. There were many models, sizes, and brands, each with a particular application and always the result of the same need: standardization, efficiency, and consistency.

Mechanical beginnings: the tilting roller

Before the first mechanized systems, fruit sorting was a manual task. Farmers and agricultural workers assessed the size, weight, and appearance of each fruit by hand and sight. Growing market demand rendered this system inefficient. One of the first mechanical solutions was the tilting roller, a simple system that allowed fruit to be sorted by size by rolling it on inclined surfaces with calibrated grooves or holes. Although rudimentary, this innovation was revolutionary for its time and of great importance.

The leap to electronics: the era of sensors

In the mid-1960s, the first electronic calibrators appeared. The incorporation of weight and size sensor systems allowed for the automation of part of the process, making it less dependent on human intervention. Pioneering companies emerged that began developing more precise technologies, replacing human visual inspection with electronic systems capable of detecting variations with very low margins of error. This stage was key to increasing processing capacity and, above all, improving product uniformity. Industries adapted to the new market demands, achieving greater consistency in customer satisfaction and efficiency in the distribution chain.

The optical revolution: the era of artificial vision

In the late 1990s and early 2000s, technological advancements brought computer vision. Grading systems began using high-resolution cameras and LED lights to capture images of each and every fruit from multiple angles, providing a complete scan of the fruit's surface. These images are processed by algorithms that identify external defects, abnormal colors, and irregular shapes—criteria that are pre-programmed into the control platforms. Subsequently, the development of near-infrared (NIR) spectroscopy made it possible to analyze the interior of each fruit without cutting it, thus providing values for maturity, sugar content, dry matter, and the presence of diseases or internal damage.

The digital revolution: AI has finally arrived

Currently, fruit grading systems are at the forefront of the digital revolution thanks to artificial intelligence (AI) and machine learning. Among the various brands and origins we see on the market, there is a race for innovation and differentiation. Modern equipment not only classifies fruit by its external appearance but also learns patterns from large volumes of data, improving its accuracy over time. These systems can identify subtle defects, predict a fruit's shelf life, and even anticipate quality trends by batch or geographic area. Furthermore, their integration with traceability and robotics systems allows for almost complete automation of the process. These systems enable segregation based on multiple combinations of selection criteria, allowing access to even the most demanding markets.

Conclusion

The history and evolution of fruit sizers not only reflect human ingenuity applied to an agricultural need but are also the result of rapid technological advancements that allow us to meet almost any market requirement. From manual sorting, through the era of mechanization, to today's intelligent systems (AI), each advancement has represented a step towards more efficient, sustainable production adapted to market demands. In a world where food quality is as important as its availability, sizers are the culmination of decades of innovation in the pursuit of the perfect fruit for each market. The immediate future will undoubtedly continue to surprise us with many more innovations.

Ricardo Acha, General Manager - Proyecta Consultoría y Representaciones, ricardo.acha@proyectasociados.com