Health authorities are trying to track down people who may have bought meat from an illegal abattoir discovered in the Swieqi valley this week.

The meat was destroyed after it was established that animals slaughtered there were not killed in hygienic conditions and the meat was not stored at optimal temperatures, Animal Welfare Department director Mario Spiteri said.

These unsanitary conditions increased the risk of food poisoning to anyone who consumed such meat, a spokesman for the Environmental Health Department said adding that initial investigations suggested the meat was meant for human consumption.

On Thursday animal welfare officers caught three men red-handed as they were killing a sheep by slitting its throat in an abandoned farm in the valley.

Another two foreign-looking men, who had turned up to buy meat, were also spotted on the scene. All five men were detained for questioning following the intervention of police and heath officials.

The three men who were allegedly operating the abattoir are expected to face court proceedings for animal cruelty and breaching health regulations by selling meat that was not slaughtered in monitored sanitary conditions.

Charmaine Gauci, head of the Health Promotion and Disease Prevention Department, explained that when meat was not refrigerated microbes multiplied, increasing the risk of food-borne illness.

"It is important that all meat is cooked properly before eating to kill off the microbes and avoid disease," she said.

In an effort to ensure meat on the market is safe for consumption, health officers regularly inspect outlets from where meat is sold. They ensure that the meat has the official veterinary stamp and traceability records, the Health Department spokesman said.

"In cases where meat is found being produced at an illegal establishment the operator is requested to furnish the department with a list of premises to which such meat was supplied," the spokesman said.

Having said that, he added, illegal operators did not always cooperate for fear of incriminating themselves.

"It is for this purpose that this department insists, as a condition of licence, that business operators purchase their products solely from approved suppliers," he said.

"In turn consumers should also ensure they purchase from duly licensed outlets... We wish to advise consumers to report any suspicious activities to the competent authorities for investigation from their end," he said.