Cold chain transport and storage family firm McCulla Ireland has been bought by investors promising to build Europe’s largest temperature-controlled business.

The transport company described the deal as a strategic partnership that marked the start of “an exciting new chapter” for the 56-year-old firm.

It said the investment was supported by a private fund with €1bn (£840.7m) earmarked for significant expansion and that the partnership brought substantial financial backing and enabled McCulla to strengthen its market position.

“While it’s never an easy decision to sell a family business, this opportunity allows us to build on our success and unlock new growth potential with the backing of a strong, like-minded partner,” said chief executive Ashley McCulla.

“Most importantly, we’re staying true to our roots – our leadership and management team remains unchanged and we’re still the same people our customers know and trust.

“We owe everything to our customers. Many of them have been with us since the early days, and we’re proud to say that many have become friends.

“Their support, feedback and partnership have helped shape who we are today,” he added.

The company said the unnamed European stakeholders were committed to preserving what had made it a success and were particularly supportive of its moves to become Ireland’s greenest logistics provider.

Last year, it secured funding for 11 HGVs powered by biogas, boosting its Northern Ireland fleet running on the fuel to 85%.

McCulla is the only company in the UK and Ireland operating bio-CNG trucks using gas produced from food waste and producing electricity via a controlled heat and power unit to power its own carbon neutral coldstore.

McCulla also paid tribute to the 300-strong workforce and said the company would not be where it was without their hard work and dedication: “Every member of our team has played a vital role in building the reputation and business we are so proud of,” he said.

Brother and sister, Ashley McCulla and Carol Thompson, who jointly took control of the business built by their father in 1992, said they would remain actively involved “for a period of time” in order to ensure continuity and support.