The frozen food manufacturer Findus was forced to recall its line of beef lasagna meals this week after testing by the British Food Standards Agency revealed that, instead of beef, the meals contained between 60 and 100 percent horse meat.

The multinational conglomerate joins a growing number of companies that have removed food products from supermarket shelves after they tested positive for equine DNA.

Though it was initially believed that the contamination occurred due to error, the FSA now says "it is highly likely there has been criminal and fraudulent activity involved."

Agency officials have ordered all food businesses operating in the region to test their beef product for horse meat and submit the results to the FSA.

Meanwhile, the deputy chairman for the UK's Labour Party, Tom Watson, claims to have evidence showing Findus knew about the horse meat contamination as early as last August.

And Shadow Environment Secretary Mary Creagh told the press today that she has been "given information about British companies who may potentially be involved in the illegal horsemeat trade," and wishes to "share this information with the police."

The FSA said it did not believe the horse meat posed a food safety risk, but did mention the need to test for the anti-inflammatory drug phenylbutazone.

Also known as "Bute," the drug is typically found in illegal horse meat, and has been shown to cause a serious blood disorder in some humans.

[image via Findus]