1 answer to 8 blueberry sorting challenges – MXM BN.2

MXM BN.2 redefines the approach to blueberry sorting. This optical sorter was built on the basis of practical experience and the challenges that companies in the blueberry industry face on a daily basis. What problems of growers, exporters and blueberry packing companies does the technology behind our sorter solve?

Problem 1: The specific nature of fresh blueberries

The automated packing process can damage delicate fruit. Contact with machine components, and above all drops between levels as the fruit passes through the line, cause blueberries to lose their natural bloom and firmness. Yet these are precisely the qualities that retail chains are willing to pay more for.

We had this in mind when designing the MXM BN.2 blueberry sorter. That is why we opted for belt transport instead of roller transport. As they pass through the sorter, blueberries move along a belt made of flexible TPU material – with no rotation and no contact points with rubber rollers. This way, we protect the blueberry bloom to the maximum degree. We also reduced the drop height to a minimum. The MXM BN.2 has a 160 mm drop, whereas most sorters and graders operate with total drops of 250–400 mm. As a result, the mechanical forces acting on the blueberry as it passes through our sorter are significantly lower than with competing machines. The outcome? Sorting blueberries with the MXM BN.2 is gentle on the product, and more firm fruit with its original bloom intact reaches the subsequent packing stages.

Problem 2: Variability of raw material

Some blueberry sorter and grader models require the operator to manually adjust sensitivity settings when switching between batches of fruit. The fruit being packed varies in firmness depending on the variety, the stage of the season, or even the time of harvest. When an inexperienced operator is required to set the rejection threshold, there is a considerable risk of error – and consequently of customer complaints.

How did we address this challenge? The MXM BN.2 has a built-in ASD – Adaptive Soft Detection system. This is an automatic system that analyses the NIR distribution of the current batch and adjusts the firmness sorting threshold in real time – for each batch individually, without operator intervention. ASD looks at the entire population of fruit passing through the optical sorter and sets the firmness threshold relative to that specific batch, rather than according to a fixed factory setting. If the batch is generally firm, the threshold is set higher. If the batch is soft and variable, the threshold is lowered and the sorter becomes more aggressive. As a result, the machine adapts on its own, and the risk of complaints caused by human error is reduced. ASD has one further function: it detects contamination of the lower camera. When the lower camera becomes dirty, NIR readings shift. ASD detects this shift and corrects the lower camera’s results in real time, without stopping the line.

Problem 3: Sorting blueberries in short batches

Another challenge is packing and sorting blueberries in short cycles. During the shoulder months of the season, lines operate at lower intensity. It sometimes happens that the breaks between batches are longer than the packing itself, and the line must be started up each time a new delivery of fruit arrives at the facility. This situation poses a challenge for large lines with graders, as starting up this type of sorter is simply not always worthwhile for smaller fruit batches.

The MXM BN.2 performs well in short-cycle packing mode. The sorter can operate at full capacity immediately after start-up. This means you can approach orders flexibly and fulfil contracts that are not profitable for facilities running graders alone. Integrating the MXM blueberry sorter into a line that already includes a grader makes it possible to handle shorter orders. In such cases, the MXM BN.2 can act as the sole sorting machine while the grader remains switched off.

Problem 4: Invisible defects

Just a few years ago, the standard for blueberry sorting was manual inspection or mechanical rejection using a calibrator. Today, the industry is moving towards optical sorting – for several reasons. There is a shortage of people willing to work in packing facilities. Even if they could be found, the human eye is unable to detect defects inside the fruit, cracks, mould foci, or berries that are too soft. Calibrators, on the other hand, operate on a single criterion only – fruit circumference. The global blueberry market has become highly demanding in terms of quality, making blueberry sorting an even more critical process. Retail chains leave no room for compromise: customers want fruit that is ripe, healthy, firm, bloom-covered, properly coloured and of a specific size.

To deliver fruit of such quality, you need to employ more advanced methods of eliminating defects. The MXM BN.2 optical sorter is equipped with two 2K cameras – one from above and one from below. The cameras scan each blueberry simultaneously from both sides, providing visibility of the fruit from the top and the bottom. Each camera captures RGB and NIR data simultaneously, delivering information on the colour and structure of the fruit at the same moment of scanning. RGB indicates ripeness – green and red berries are identified immediately. NIR indicates internal structure – it allows a soft berry to be detected before it even looks overripe on the outside.

Problem 5: Blueberry sorting in a small packing facility

A growing business needs space – and a packing facility, once designed, is not a structure built from building blocks. The dimensions of the building impose constraints, and food production standards define the requirements for rooms that can be adapted for production purposes.

Existing infrastructure can be limiting for a growing business and evolving market expectations, which is why we made sure that our blueberry sorter combines performance with compactness. Let the numbers speak for themselves, as they best illustrate the essence of this point. The MXM BN.2 can sort up to 3 tonnes of blueberries per hour, while occupying just 3 m². That is the best throughput-to-footprint ratio among optical blueberry sorters. In other words, you only need to allocate 3 m² in your packing facility to be able to effectively sort 3 tonnes of fruit per hour.

Problem 6: The cost of maintaining a sorting machine

An investment in a machine or an entire blueberry line should take into account the cost of maintaining the infrastructure over time. TCO – the total cost of ownership – is not only about spare parts or repair expenses. It also includes downtime, such as the time required for changeovers or equipment cleaning. Only a machine that is running is earning. One that is not generates losses.

Every machine in the line gets dirty through contact with soft fruit – and a sorter is no exception. On various parts of the sorter – the cameras, the fruit-conveying belt – juice stains, fruit residue and field debris accumulate. For the machine to operate efficiently and for the entire packing process to meet sanitary standards, regular – ideally daily – cleaning of the line is required. The designers of the MXM BN.2 blueberry sorter paid close attention to its open-frame construction, which translates into easy access to spare parts and components. As a result, the daily cleaning of the sorter takes approximately 20 minutes. Compared to graders – whose cleaning can take up to 8 hours – this is a significant difference.

Problem 7: Service downtime

Besides cleaning, machine downtime is caused above all by breakdowns. Situations where an entire line stands idle at the peak of the short blueberry season due to a single faulty machine are far from uncommon. You are waiting for a technician, time is passing, fruit in storage is losing quality, drivers are growing impatient, and the client is browsing competing suppliers’ offers. Sound familiar?

Working with the MXM BN.2, you keep downtime to a minimum. First and foremost, this blueberry sorter offers a remote problem diagnosis option. In the event of a breakdown, our technician connects to the machine via the internet and informs the operator of what needs to be done to get the sorter back up and running. This way, you turn lost days into lost minutes. Moreover, as the manufacturer of the device, we maintain a spare parts inventory that we dispatch to customers without delay whenever needed.

Problem 8: Blueberry sorting and mechanical harvesting

The issue of labour shortages in agriculture is linked to another challenge. Harvesting machines are appearing on blueberry farms with increasing frequency. With mechanical harvesting, the importance of the sorting stage in the packing process grows, as a greater number of unripe and defective fruit enters the hopper, along with leaves, stems and other contaminants.

With mechanical harvesting, blueberries may be damaged on both sides. Thanks to its two cameras, the MXM BN.2 sees the fruit from both sides, and therefore does not miss defects that may go undetected by a machine inspecting fruit from one side only. The MXM BN.2 blueberry sorter is capable of quickly eliminating fruit that fails to meet criteria and other harvest debris from the process. Positioned ahead of a grader or sorting table, it works excellently as a pre-sorting machine.