Burgers containing horse meat could have been made from "diseased or injured animals", say environmental health experts in the UK.
Health concerns have been raised by the Society of Chief Officers of Environmental Health in Scotland (SOCOEHS) over the safety of the beefburgers which were found to contain horse meat.
John Sleith, chairman of the organisation, said there was "no way of telling whether the meat is safe" because these burgers had bypassed official inspection.
He continued: "There is no information on how the horse meat came to be in the burgers, so there is no way of telling whether the meat is safe to eat -- it could be from diseased or injured animals.
"If it hasn't come through the official inspection system, then there is no confidence that it is completely harmless."
Mr Sleith also said the current scandal was an example of "food fraud", which was becoming an increasing problem.
"This episode is indicative of a growing trend we are finding, where there is substitution of meat products. Food fraud is big business and food inspectors have to be alert to it.
"Recently, for example, there have been cases of cheap beef being sold as more expensive lamb in curries.
"It is important that the public are well informed about food ingredients and that they can have confidence in what is being produced."