The three-year deal will see the logistics company collecting around 50 million litres of milk a year from farms in Central England, North Wales, Lancashire and Yorkshire.
The operation, which began last month, is based at SJ Bargh’s Endon depot near Stoke-on-Trent.
While the company already delivers more than 3 million litres of milk each day, the contract brings new challenges as organic farms are fewer and spread over a larger area than conventional dairy farms.
Omsco, which was set up in 1994, supplies the likes of Sainsbury’s, Robert Wiseman Dairies and Yeo Valley Organic.
Michael Sidley, commercial director at SJ Bargh, says: “Our expertise in the milk logistics sector, along with our experience with organic products has enabled us to meet the logistics requirements of our new customer.”