But it all started with a panini about 10 years ago, explained co-operative manager Robin Nitschke.
"It all began when we first tasted tamarillo relish on a panini at the Kings Cafe in Silverdale," Mr Nitschke said.
"Shortly after that we bought a 10-acre lifestyle block in Whangarei and decided to plant tamarillo trees to make tamarillo relish, jams, jellies, sauces, and later vinegar dressing."
Initially Robin and Heather Nitschke sold the products in local stores then weekly at farmers' markets in Northland, which they had been doing for the past seven years.
During that time they built up a large number of regular customers with some willing to travel long distances to buy their products.
"All our validations for our products have been by way of feedback from these customers - we asked what they like and why, and what they don't like and why not."
Mr Nitschke said that because of the small size of the tamarillo industry, with few products on retailer shelves, they were confident they were on to something unique.
"It was with this in mind that we built a commercial kitchen in our orchard [at Maungatapere] and began to make and sell tamarillo products.
"When Auckland retailers wanted to stock our products we realised we needed to upscale and commercialise our business," Mr Nitschke said.
So they contracted an Auckland-based food manufacturer to produce the products and formed the NZ Tamarillo Co-operative Ltd (Tamco) to secure a constant supply of fruit.
Tamco now buys 90 per cent of the national tamarillo crop, handling more than 350 tonnes per year.
This approach also adds value to the fruit and "substantially increased growers' returns".
"In this way [with the co-operative] we can control the commercialised added value product at both ends of the supply chain."
Mr Nitschke said the biggest obstacle they were up against initially was a lack of knowledge.
"This was not surprising as our requirements were unique because not only is tamarillo a special, quite rare fruit but the process that we're trying to achieve to manufacture our relish and vinegar dressing had never been attempted before in NZ and, from enquiries that we made on the internet, it hadn't been tried overseas either.
"We quickly discovered that what works well on a small scale to produce product for the farmers' markets cannot be replicated to a large-scale operation.
"We visited a number of food manufacturers and equipment suppliers but there was nothing available that would effectively allow us to both infuse the tamarillo with the red wine vinegar and ensure absolute clarity of product for the vinegar, and there was no machine or equipment that would extract the fleshy pulp from the tamarillo and leave the bitter pith remaining on the skin.
"In fact there was nothing available that we could even modify to suit our requirements.
"So, we resigned ourselves to having to design and build this equipment ourselves - and that's what we did," Mr Nitschke said.
"After 18 months of trial and error, and at a considerable cost, we developed and constructed the purpose-built equipment required for the production of our unique Tamarillo Vinegar Dressing, and have implemented an extraction method to effectively separate only the tamarillo pulp from the skins for our Tamarillo Relish."
During the past seven years sales have increased by 23 per cent per annum on a per market basis.
The brand is currently distributed into some New World and Pak'n'Save stores in Auckland, with expansion now to other areas. Tamco is also about to introduce the products into Countdown stores.
They are working to launch both products into Australia and hope to sign a joint manufacturing contract with an American manufacturer to introduce the products into the United States.
