Le Sueur-based Davisco International, one of the country’s largest privately held cheese companies, is being purchased by Canada’s biggest dairy cooperative.

Terms for the deal announced Tuesday weren’t disclosed. Davisco has over $1 billion in annual sales and 900 employees, along with a cheese factory in Le Sueur, Minn., and an ingredients plant in Nicollet, Minn., 25 miles to the southwest.

The purchaser, Agropur, said the Davisco deal is the biggest in its 76-year history, doubling its U.S. processing operations. Agropur, based near Montreal, currently has operations in Preston, Minn., and Maplewood.

Jon Davis, Davisco’s CEO, said Davisco and Agropur have built “very similar cultures.” The deal “increases in an important way our capacity to meet our clients’ needs for cheese and dairy ingredients in the U.S.,” he said.

Davisco officials did not return calls for comment.

Serge Riendeau, president of Agropur, said the deal plays into dairy consolidation trends. “The world dairy industry is consolidating at an accelerated pace, and our acquisition of Davisco supports our objective of increasing our global presence.”

Pete Hardin, editor and publisher of trade magazine the Milkweed, said Davisco is one of the largest family-owned U.S. cheese processors. The company is known as the leader in the market for whey, a protein-rich byproduct of cheesemaking.

“Where Davisco has really shined is in the development of whey,” Hardin said.

Whey is the building block of many dietary supplements and fast-growing grocery products such as sports drinks. Davisco has been “at the pinnacle of dairy protein innovation,” Hardin said.

The Davisco deal with Agropur does not involve Davis Family Dairies, a milk-producing operation based in southern Minnesota that manages more than 20,000 head of cattle and produces 570,000 gallons of milk a day.

The Davis collection of businesses also includes the quartz countertop manufacturer Cambria and Sun Country Airlines.

Earlier this month, Forbes magazine added the Davis family to its list of richest American families. The maga­zine said the family of Mark Davis, son of company founder Stanley Davis, has a net worth of $1.7 billion.

Davisco was founded in 1943 by Stanley Davis after he acquired the St. Peter Creamery and began selling butter to the government during World War II. In 1972, under Mark Davis, the creamery operation shifted to cheese production.

The family started Cambria in 2001 in Le Sueur, where it grew to be the largest ­family-owned producer of quartz countertops in the United States.