The very first blueberry sizer, installed by MED Automation for Gossamer. Photo courtesy.

Growth in the production volumes of blueberries in South Africa has been significant, with some reports indicating a 30 per cent increase per annum since 2008. 

Blueberries are a labour-intensive crop. To meet specified export standards, each berry has to be sorted individually according to size and defects, if any. In some export markets, blueberries are often grown in open fields and are therefore more susceptible to the elements, including insects and birds. These berries are even machine picked, resulting in mechanical damage. 

In South Africa, producers grow blueberries in tunnels where the best berries can be selected and handpicked to ensure the best possible quality.  This has the advantage that the quality of the blueberries are more consistent, requiring less sorting for defects and blemishes, after harvest.

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To address the challenge of handling higher volumes effectively, MED Automation, situated in the Paarl, developed the first unique mechanical blueberry sizer. The system involves multiple spool-type sizers to separate the berries into the required sizes.  The much needed high volumes and high speed requirements are met with this invention, also resulting in lower overall costs.

The berries are tipped from orchard lugs after which the sizer removes undersize berries before being graded by hand on a sorting table.  After this initial quality sorting, the berries are sized in series, into size groups as indicated by the client.

"The first sizer was introduced late in 2018.  The first season went well with the client confirming that sizing was very accurate.  Capacity is estimated at between 3 and 5 tons per hour, depending on the berry size.

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Gossamer's new PF-400 punnet filler was incorporated into the design from the onset.  For Gossamer we incorporated their multi-head weigher which places berries in smaller containers", says MED Automation's founder, Gerhard Visagie.

In South Africa, blueberries are still a rapidly growing market, even in neighbouring countries such as Namibia and Zambia.  The inclusion of the upgraded mechanical sizer will certainly aid farmers to meet the increasing export volumes, while simultaneously ensuring they don't fall behind in the picking window.

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