More than 200 jobs in the are under threat after supermarket milk supplier Dairy Crest announced plans to close a North West dairy.
The proposed closure of a glass bottling dairy at Aintree means 220 jobs are at risk.
The company also expects to close a site at Fenstanton in Cambridgeshire employing 250 people.
Dairy Crest said a recent £75 million investment programme enabled it to transfer work to its three polybottle dairies at Severnside, Chadwell Heath and Foston in Derbyshire.
The company is battling an "extremely challenging" market for liquid milk and said the plans, which are subject to staff consultation, would help it reduce costs and sustain profitability.
Dairy Crest, which employs 4,000 people in its dairies business and 6,000 people overall, also announced that its current contract to supply liquid milk to Tesco will not be renewed in July.
Around 3% of the company's liquid milk sales are made to Tesco and Dairy Crest said the loss of the contract was not a factor in the decision to close the two dairies later this year.
The demise of the Aintree site reflects the fall in sales of milk in glass bottles as residential trade continues to decline and customers increasingly opt for plastic bottles and milk bags.
Dairy Crest also has a food division which makes leading brands such as Cathedral City, Country Life and Clover.
Chief executive Mark Allen said the dairy closures would protect the future of the dairies side of the business.
He added: "The decision to consult on the closure of our Aintree and Fenstanton facilities has not been taken lightly, but we believe that this proposed restructuring of our dairies business is the right decision for the long term."