The Ealing council has warned small food retailers about the dangers of selling illegally imported food after several items were found in shops across the borough.
By conducting unannounced visits to local shops over recent months, environmental health officers seized illegally imported items including vacuum-packed quail eggs in brine and marinated mackerel, both originating from Japan.
Animal products from outside the European Union require certification to be lawful and must come from an approved producer in an approved country.
Local shop owners are being warned of their responsibility to check the source of their products and ensure they meet the UK's food safety and labelling laws.
Councillor Will Brooks, cabinet member for environment and transport, said: "Food that comes in from outside the EU is produced under different food safety laws and may not be up to our standards.
"We will continue to visit local shops, wholesalers and importers to ensure they are doing the right thing and are fully aware of their responsibilities."
