Babylon Supermarket Limited pleaded guilty to several food offences including selling food not correctly labelled and failing to put in place and maintain a documented food safety management system.
Babylon was fined £2,000 following a hearing at Hull Magistrates' Court on June 7.
Trevor Todd, assistant head of service for public protection at Hull City Council, said: "This case shows how important it is to implement a food safety management system. A series of simple daily checks would have prevented this problem from occurring.
"Suitable advice had been provided by environmental health officers and not acted upon. A use by date is applied to high-risk food that is likely to cause illness if consumed past this date."
The problems were brought to the council's attention during a routine inspection of the premises in January.