New restrictions on carcass inspection could mean diseased meat ending up in the supply chain.
Inspectors in abattoirs will no longer be able to cut open pig carcasses to check for signs of disease under new European regulations, supported by the Food Standards Agency.
Instead they will have to assess each carcass visually to reduce the risk of cross-contamination and the spread of bugs like E. coli and campylobacter.
Ron Spellman, who is director general of the European Working community for Food inspectors and Consumer protection, told the BBC: "Last year we know that there were at least 37,000 pigs' heads with abscesses or tuberculosis lesions in lymph nodes in the head. They won't be cut now.
"There's no way to see those little abscesses, little tuberculosis lesions without cutting those lymph nodes."
The meat from pigs' heads is destined for processed foods such as pies and sausages.