Wincanton has begun consultations to make approximately 75 staff redundant at the Bridgwater, Somerset, distribution depot it operates for Somerfield.
About 400 people currently work in warehouse, management, administrative and clerical roles at the site.
The decision follows a review by the grocery chain of its distribution network, following the £1.6bn sale of its UK stores to the Co-operative Group last March.
A Somerfield spokesman says: "Both Wincanton and Somerfield wish to make it clear that the move in no way reflects the commitment and contribution of the Wincanton team in Bridgwater, whose performance has been exemplary.
"Somerfield and Wincanton will continue to work together to ensure that Somerfield stores and our customers continue to experience the high level of service and availability they have come to expect."