South African fruit and vegetable exporters are increasingly tuning into the benefits of adequate packaging on fruit quality and shelf life.
And they’re now able to draw on scientific evidence thanks to research by the University of Stellenbosch’s department of horticultural science into packaging and its impact on the cold chain.
According to consultant Andy Connell, while growers have increased their focus on packaging, the sector still requires much more research and innovation to develop optimal efficiency in the cold chain.
“The traditional packaging of fruit has had to be re-examined,” he told FTW. This has led to some change and improvements in the packaging of different fruit types. Going from the traditional cardboard box with two holes for ease of carrying, packaging research has proved that not only are holes required for ventilation, they also need to be a specific size to suit the fresh product they protect and carry.
“Research is now also indicating that the shape of the holes and their positioning have an impact on the efficiency of the cooling process,” said Connell.
“Air flows horizontally in the traditional cold rooms on the landside whereas the specialised reefer vessel cooling airflow is vertical. While the super efficiency of the reefer vessel masked this factor, the 12-metre reefer container could not effectively cool down product in the traditional cartons and an erosion of the airflow was caused, weakening the cold chain and ultimately damaging fruit,” he said. “The design for packaging is now favouring super vents – allowing air to flow vertically through the cartons. The cold air has to come up through the fruit.”
Where the holes are situated and their size are critical in achieving this. The shape is also important.
“It has taken a long time for packaging to evolve from the design of the old styles. However, there is certainly now a better understanding of the importance of the shape of the holes, the size and positioning on a carton. The trend is now for oval shaped rather than round,” he said. “This stops the fruit from nesting in the holes when moved.”
Cartons were not always block-stacked one above another, explained Connell, but alternate layers were turned 90 degrees to create a more secure stack. The traditional packaging had ventilation holes blocked by the carton beneath. Another trend, said Connell, was the move towards standardised packing rather than opting for individual packaging designs.
“The carton is a crucial part of cold chain efficiency, playing a vital role in the fruit condition. Not only does one need a firm box that can protect the fruit, it also has to support ten to fifteen more layers of cartons on top of it. The citrus industry in South Africa is well advanced in using standardised designs for its cartons. We are now seeing the pome industry move in the same direction.”
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Not only are holes required for ventilation, they also need to be a specific size to suit the fresh product they protect and carry.
