2 Sisters Food Group workers stage strike
Up to 800 staff at 2 Sisters Food Group are staging what they say is the first of three 24-hour strikes.
The union Unite said workers at three sites in the West Midlands walked out in a dispute over pay and conditions.
Staff mainly deal with packing chicken, but also supply fish and baked and frozen products to shops including Tesco and Marks & Spencer.
Andrew Hanson from 2 Sisters said supplies to supermarkets were unaffected.
The strike affects the firm's plants in Smethwick, West Bromwich and Lincoln Street in Wolverhampton.
'Seven day operation'
Staff began the strike at 06:00 GMT and about 500 gathered outside the headquarters in West Bromwich.
Unite's regional officer Des Quinn said staff had voted overwhelmingly to take a stand against a "paltry" pay offer.
Mr Hanson said the pay offer on the table was above inflation.
He said: "We want to sustain and create jobs at these sites to maintain demand and move to a seven day operation.
"But we need our workforce to come with us to do that."
More strikes are planned for 18 and 21 December.