A Tesco employee in Wokingham, Berkshire, was stunned after spotting bags of white powder inside a carton of bananas.
The employee discovered five bags of what is suspected to be cocaine while unpacking the fruit.
The bags each weighed roughly 1kg and are believed to have a total street value well above £600,000.
Police were called on the scene after the carton imported from South America was discovered.
"We were called on 22 July to Tesco at Finchampstead Road, Wokingham to reports of packages being found in a consignment of fruit. They are believed to be class A drugs. Officers are investigating," said the Thames Valley Police, reported The Independent.
Most of the Tesco bananas reportedly originate from Costa Rica farms from where they are delivered to distribution centres across the UK.
"[Drugs being found on school premises is] worrying as it will often only be the tip of the iceberg of what young people are encountering on the streets," said Chris Keates, general secretary of the National Association of Schoolmasters Union of Women Teachers (NASUWT ), reported BBC News.
"Teachers and school leaders are always alert to the potential for young people being involved in drug or alcohol abuse."