One in four slaughterhouses is failing to take basic hygiene precautions to stop contaminated meat reaching the public, the Bureau of Investigative Journalism can reveal.

An analysis of government audits carried out at more than 300 abattoirs in England, Wales and Northern Ireland identified major hygiene failings in more than a quarter of the meat plants. The failings could expose consumers to serious food poisoning illnesses such as E.coli, salmonella or campylobacter. The true situation may be even worse.

The investigation has also revealed that official Food Standards Agency (FSA) records were falsified to conceal true levels of meat contamination at an abattoir processing pigs, cattle and sheep. A whistleblower said data relating to the contamination of carcasses was mis-recorded in order to mask poor hygiene practices at the plant - potentially allowing dirty meat to enter the food chain.

The Bureau analysed the most recent audit reports resulting from official inspections by the FSA of 323 abattoirs in England, Wales and Northern Ireland. One key test that slaughterhouses have to pass is that “all handling and processes from slaughtering to despatch are done in a way that avoids the contamination of meat and offal entering the food chain”.

Out of the abattoirs audited, 86 did not meet that benchmark - with 'major' hygiene breaches found. They include instances of carcasses coming into contact with the factory floor (often dirty with the detritus of slaughter), cutting equipment not sterilised or washed adequately, and meat splashed with dirty water potentially containing faecal matter.