Tesco is facing strike action from cleaning and catering staff at its depot in Didcot, Oxfordshire.
The dispute involves cleaning and catering staff employed on an outsourced contract. The union said it resulted from a refusal to negotiate over a pay increase.
It said cleaners were on pay rates of as little as £11 an hour, while catering staff were paid the minimum wage of £10.42 an hour.
The workers have announced two initial 24-hour strikes beginning on Friday 1 September and Thursday 7 September, followed by a three-day -strike beginning on Friday 15 September and a further three-day strike beginning on Thursday 21 September.
“Atalian Servest can fully afford to give our members a decent pay rise. Its failure to do so is a cynical attempt to further boost its profits at the expense of its workers,” said Unite general secretary Sharon Graham.
“Unite is entirely focussed on the jobs, pay and conditions of its members and the workers at Atalian Servest in Didcot will be receiving Unite’s complete support.”