Greek news service AMNA reported that some unmarked barrels contained “recycled” alcohol, left by patrons.
It was common for bartenders to collect unfinished spirits to sell back to tourists.
The raids come as Greece investigates the death of UK tourist Hannah Byrne, 22, in Kavos. The police officer died after a suspected tainted alcohol case, less than 12 hours after arriving at the seaside resort. She was found early on Friday morning last week, after a minor fall.
Chief medical officer Yannis Aivatidis said that alcohol was detected on the woman’s breath.
“There are questions as to what kind of alcohol she consumed,” Aivatidis told local news.
“Had it been illicitly tampered with? Was she so intoxicated because methanol was in the alcoholic drinks she had consumed?”
A toxicology report was being conducted to find if tainted alcohol could have played a part in Byrne’s death.
Kavos is the southernmost beach on the island of Corfu. Its main tourist appeal is to young holidaymakers from Britain, Germany and Northern Europe, who come for sun, cheap drink and a 24-hour party reputation.