Johannesburg - A bag containing cocaine with an estimated street value of R7 million has been seized at OR Tambo International Airport (ORTIA), the SA Revenue Service said on Tuesday."The 26.48kg of cocaine is believed to be amongst the biggest cocaine busts ever at ORTIA. The luggage and all its contents were inspected [on Monday] after the airline had failed to locate the owner of the bag," it said. "During the compulsory inspection, Sars customs discovered 19 compressed blocks (wrapped in a brown tape) and 7 plastic bags containing a ‘cream colour’ substance. A drug test was administered on the substance and it tested positive for cocaine."According to a tag on the bag, it was destined for London from South Africa."Experience gained from previous incidents suggests that the drugs could have originated from South America," Sars said."It is suspected that such shipments are brought into South Africa by one passenger then handed over to another passenger on an onward flight to Europe or Africa."The cocaine was handed over to the police for further investigation.