Canning technology helps NZ exports

Press, 29 June 1983, Page 21

Canning technology helps NZ exports

The introduction of a new can-lining technology by AHI Metal Containers is helping New Zealand horticultural exporters retain and develop important European markets. The new method of lining a can to resist the highly corrosive juices of fruit, such as boysenberries and blackberries, was developed in Europe. As a result the European marketplace has become accustomed to the appearance of this type of can lining, with its associated enhancement of shelf life. Without the new lining, exporters were told, some products had a very limited appeal to the European consumer. After discussions with their horticultural exporting customers and using their own information resources, AHI Metal Containers established that New Zealand horticultural products would not reach their full marketing potential in Europe if the new internal coating system was not used. It meant some very fast action if this season’s fruit was to be accepted in Europe. Consequently AHI Metal Containers installed equipment to produce cans with the new linings for this season’s boysenberry crop

which was actually canned in December. Since then New Zealand blackberries have been processed and now Kiwi fruit is on the canning lines. The group manager for AHI Metal Containers, Mr Gary’ Hodgson, says the new lining is a white, pigmented modified epoxy lacquer and this is combined with a polyester powder side stripe on the internal welded side seam of the can to keep contact between the can and its contents to an absolute minimum. “We are able to apply the internal protective stripe on a machine set up as an integral part of our new Swiss-made Soudronic welding process,” said Mr Hodgson. “The polyester is actually in a powdered form. We charge the particles electrically and this enables us to apply them electrostatically. The particles adhere

to the internal seam and are then melted in place by a radio frequency heating unit This gels the powder into a very tough, chemical resistant material,” Mr Hodgson explained. The epoxy powder lacquer is applied before this, when the cans are still flat sheets of metal. The sheets are roller coated and then baked in an oven, similar to the enamelling process, and the end result looks very similar to enamel. “We also treat the internal ends of the cans the same way, so the final product is a can interior that not only looks very good but provides a chemical resistance to anything likely to be put in the can,” said Mr Hodgson. The photograph shows a Kiwi fruit canning line at Mount Processors (NZ), Ltd, Mt Maunganui, using the new-style cans.