This is the disgusting scene that forced supermarket giant Asda to close one of its stores for 10 days and pay a £664,000 fine.
In a single year, the retailer's own pest controllers visited the store 72 times because of a plague of vermin.
But it was only when customer Mike Draycott, 58, ate cheese rolls from the store covered in "poisonous" mouse droppings that environmental health officers and the chain closed the bakery last September.
Mouse faeces was found in bags of flour, food packaging, trolleys used for bread and the production area inside the filthy bakery at the Park Royal store in west London.
A frozen mouse was found inside the entrance to the walk-in freezer and traps were left strewn across the floor, Uxbridge Magistrates' Court heard.
Defending, Jonathan Goulding said Asda had "genuine regret and remorse".
Asda admitted four charges of breaching the Food Safety Act: failing to keep the premises clean, failing to ensure adequate procedures are in place to control pests, placing unfit food on the market and construction of premises which failed to control pests.
The store has had a new bakery fitted and the ovens were deep cleaned, plus a host of other measures introduced.
The supermarket was fined £664,000 and ordered to pay £500 compensation, costs of £7,599 and a statutory surcharge of £120.