Dutch-owned Tulip has taken over the pork processor George Adams, creating the UK's largest pigmeat supplier.
The deal, for an undisclosed sum, will leave Tulip with almost a third of the national pig kill and sales of £1.2bn if it clears regulatory hurdles. But pig producers said the move could spell trouble for them.
"People will be nervous about a Danish company taking a greater share of the UK market," said BPEX chief executive Mick Sloyan. "We need to know Tulip's long-term vision before we know whether this is positive or negative."
Tulip said it hoped for approval from the competition authorities by the end of November and claimed consolidation would benefit the whole supply chain.
"This transaction will help us to supply the UK consumer with an even wider range of high-quality products," said Tulip chairman Carsten Jakobsen. "We are confident our involvement will bring further benefits to all parties."