Westland UHT milk heads to China, Fiji

While most of this is done at the company’s main plant at Hokitika, its UHT plant at Rolleston, near Christchurch, produces milk for China and other markets. Reporter Peter Burke visited recently.

Westland Milk's plant at Rolleston is ideally located for a company that collects milk in two distinct regions – West Coast and Canterbury. For a start the railway line runs right beside it and there is an inland port.

The milk from farms in Canterbury comes into a ‘reception area’ -- your typical factory collection area with three 250,000L silos where the milk is first stored.

UHT manufacturing manager David Reid says once the milk is tested some is kept for processing into UHT, while the remainder gets reverse osmosis treatment whereby about half the water in the milk is removed, concentrating the milk solids and so reducing the cost of moving them by road or rail to Hokitika for processing mainly into powders.

The water extracted from the milk is then processed for re-use at the factory; it does not go down a drain.

The amount of milk handled by Rolleston varies from season to season; in better seasons the plant can handle at least one million litres. After processing, this milk and all the products made at Hokitika come back to Rolleston; powders are warehoused, butter and other products go into a cool store.

According to Reid, the UHT plant at Rolleston is not large and is very much in its infancy.

“We produce 1L and 250ml cartons, and we can also do a bag-and-box -- a large bag of capacity 20L to 1000L. These large packs are mainly for the food service or manufacturing sector.”

The UHT process at WMP Rolleston is the same as other plants: the milk comes in, is standardised, then heated to 140oC for four seconds, cooled to 20oC and then it’s ready for packing in standard Tetrapak cartons.

“We pack it antiseptically which ensures the product is free of bacteria that could cause spoilage or food safety issues. In the case of UHT milk, this gives it a shelf life of nine-twelve months. We sample throughout the run for batch uniformity and sterility – the latter is critical. We can also trace all our products from the farm to the time they come off the production line.”

Not only is the milk sterilised, so are the Tetrapaks. These come off a belt and are opened up to form a tube into which the milk is fed. An unusual feature of the 1L packs produced at WMP is their screw top.

“We are one of the few installations in NZ -- maybe the only one -- that runs the Tetrapak heli cap. During the manufacturing process we get a cap glued into the top of the pack and as you open the pack the action of opening it forces a cutter to go down into the pack and cuts it open. Until then the pack is completely sealed which is great for quality and safety and security.”

Whipping cream is also made at the plant and this has a shelf life of about seven months.

All the product made at Rolleston is made to order, much of it for China, Fiji and Malaysia, and mostly exported because the NZ market for UHT milk is small.

The site at Rolleston is set to expand: work is due to start soon on a stand-alone infant formula blending and canning factory, a joint venture with the Chinese paediatric milk formula company Ausnutria; WMP will have a 40% stake in the company, to be called Pure Nutrition Ltd.