Bangla Store, a grocery shop on the Rockingham Estate, has been fined £6,000 for multiple breaches of food hygiene regulations.
During a routine food hygiene inspection of the Harper Road store on 22 February, Southwark Councils's food safety team identified a catalogue of failings including signs of mouse activity and overall poor cleanliness.
Officers found that there was a "heavy infestation" of mice and that the shop sold food that was "unfit for human consumption for reasons of contamination by mouse droppings".
The management of the establishment was also found to be substandard and officers used their powers to close the shop to protect the public from likely harm.
At Camberwell Green Magistrates' Court, owner Zarar Ahmed Mir pleaded guilty to all eight charges under Regulation 17 (1) of the Food Hygiene (England) Regulations 2006.
Mr Mir was fined £6,000 for the eight offences. The court required him to pay a victim surcharge of £15 and costs of £1,215 payable in instalments of £500 per month.
Cllr Richard Livingstone, cabinet member for finance, resources and community safety, said: "We routinely see a good standard of food preparation maintained by food outlets across Southwark.
"Unfortunately, instances like this show us that we need to continue to be proactive whilst maintaining a tough stance on offenders who put the health of our residents at risk."