Decomposing dead mice and mouse droppings were found by environmental health inspectors examining a Thai restaurant’s kitchen, a council said.
They found the rotting rodents and extensive grease during an routine but unannounced visit of Chaophraya in Liverpool One in March 2016.
At the city’s magistrates’ court, owners the Thai Leisure Group Ltd admitted two food safety breaches.
The group was fined more than £32,500, Liverpool City Council said.
The restaurant was immediately closed – with the co-operation of the manager – due to the imminent risk to public health, the council said.
Officers were also provided with an earlier audit report from an independent consultancy company instructed by Chaophraya.
This noted they were “very concerned” about an “escalating” pest problem.
The report had recommended the restaurant’s closure pending a deep clean of the entire premises.
Officers were invited to revisit the restaurant on 21 March where it was found conditions still presented an imminent risk to health and the restaurant was not allowed to reopen.
It was finally allowed to reopen the following day after further improvements were made.
The restaurant was subsequently awarded the lowest potential food hygiene rating of zero out of 5, indicating that urgent improvement was necessary.
Councillor Steve Munby said: “This case sends out a strong message that substandard hygiene in any food outlet across the city will not be tolerated, and our experienced team of environmental health officers are prepared to prosecute any business who puts their customers at risk.”