Greene King has been fined £25,000 plus costs over breaches of food hygiene at a managed pub in Winchester, Hampshire.
The pub operator said it was "mortified" to learn of the problems at the Royal Oak pub.
At Andover Magistrates Court, Greene King was fined £25,000 plus £6,500 costs after pleading guilty to 10 charges relating to failure to comply with food safety legislation.
Also in court was Scott Ryder, former manager of the Royal Oak. He entered no plea and will appear in Crown Court at a later date.
The prosecution by Winchester City Council was bought following a routine inspection by environmental health officer (EHO) Adam Spencer in October 2006, and a follow-up visit in February 2007.
The inspection found several pieces of equipment, work surfaces, floors and walls to be in a poor state of cleanliness. After the second visit, the pub voluntarily closed due to a leak from a waste water pipe that discharged into the kitchen.
Winchester councillor Frank Pearson said: "It is disappointing that we have had to prosecute yet another food business in our city. Food businesses cannot afford to relax their standards when they are providing food to the public, especially when they have already received previous warnings."
Peter Hebblethwaite, Greene King operations director for town local pubs, said: "We were mortified to find such a dreadful situation at the Royal Oak and unreservedly apologise to the pub's customers. Immediate action was taken, a new management team was instated and a complete overhaul of hygiene procedures took place.
"We can now offer total assurance to customers that the kitchens are pristine and that food standards are top priority."
New managers have been appointed at the pub.