BERLIN, July 15 (Reuters) - Bridgepoint BPTB.L has agreed to buy a majority stake in German laboratory testing company GBA Group from Ardian in a deal valuing the business at more than €1 billion ($1.2 billion), a person familiar with the matter told Reuters on Wednesday.

GBA operates about 100 sites across Europe, North America and Asia-Pacific, providing testing services to more than 60,000 customers in industries including food, pharmaceuticals, chemicals, medical devices and cosmetics.

The deal is the latest sign of private equity interest in testing, inspection and certification companies, which have benefited from tighter regulation and rising demand from companies seeking to verify product safety and supply chains.

Bridgepoint has previously invested in testing businesses including Element Materials Technology, LGC, Fera Science and NMi.

During Bridgepoint's ownership of Element, the company expanded its laboratory network, quadrupled revenue and added more than 5,000 technical specialists, the source said.

Ardian did not immediately respond to a request for comment.