FILTHY food dipped in bleach to make it appear fresher is thought to have been sold across Kirklees.
The revelations came after two brothers were jailed for running a filthy meat cutting plant.
Food experts believe lives were put at risk as the business racked up huge profits.
Yakub Yusuf, his brother Ibrahim Yusuf and his stepson Nabil Allibou ran Direct Halal Meat and Poultry Ltd in Dewsbury between October 2007 and March last year.
The business shipped halal poultry and red meat to shops all over the north of England – including Huddersfield, Dewsbury and Ravensthorpe – and is estimated to have clocked up £500,000 sales in just over four months of business.
Leeds Crown Court heard on Friday how Yakub Yusuf, 58, of Warley Road, Bradford, was already banned from running a food company when he began the venture with his 48-year-old brother in the autumn of 2007.
Yakub Yusuf was jailed for four-and-a-half years and Ibrahim Yusuf, of South Street, Savile Town, Dewsbury, to 30 months for a string of serious breaches of food health and safety law.
Nabil Allibou, a 25-year-old interpreter and university student who speaks four languages, financed the plant with £25,000 while the brothers ran the business.
The court heard that Yakub Yusuf had previously managed an abattoir in Shelf, Halifax, which had seriously breached food hygiene regulations – dramatically leaking animal waste out of the premises to form what was described as ‘a river of blood’.
The breach lead to a prohibition order in 2004 banning him from managing a food company again.
Yet the brothers stepped in to run a meat-cutting plant when a company called AF Halal Meat and Poultry lost its Food Standards Agency licence and subsequently closed down in July 2007.
Three months later, Allibou approached the owners of the property to take over the lease from AF Halal Meat, acting as director for a new company called Direct Halal Meat.
The Yusuf brothers then ran it on a day-to-day basis.
The company began operations on October 27, 2007.
Leeds Crown Court heard how Allibou had very little involvement in the unhygienic plant at the Bretton Street Enterprise Centre, Savile Town, Dewsbury, which had no authorisation from the Food Standards Agency (FSA). Just four days after the Yusuf brothers had opened business, they were rumbled following a chance visit by an Food Standards Agency representative.
Prosecutor Howard Shaw said: "The unauthorised operation came to the attention of the authorities within a few days by accident."
An FSA representative called on the premises in error, believing she was attending another premises.
"She saw a lorry unloading sheep carcasses and she spoke to a man who said he was the plant manager.
"He said they had started cutting meat that week and were going to contact the Food Standards Agency for approval," said Mr Shaw.
The FSA launched an investigation and monitored the poorly-run plant through CCTV cameras twice between December 7 and December 13 and again between February 19 and March 6.
At one point in the footage, meat which had been left on the floor was gnawed at by a cat before being picked up by an employee and taken into the plant. Unclean meat from the plant was found to have been shipped to shops across the north of England including Huddersfield, Dewsbury, Manchester, Sheffield, Bolton, Bradford, Rochdale, and Wakefield.
Police and Environmental Health Officers raided the plant in March last year and closed it down after finding appalling conditions.
The premises and equipment were filthy. One mincing machine contained decomposing meat, the sink was not working, there was no soap or drying facilities and meat carcasses were left exposed.
Prior to the sentencing, Tracy Bousfield, senior manager at Kirklees Environmental Services, said: "There was a mincing machine that had not been cleaned for some time and had decomposing meat in it.
"There was a plastic tub on the floor with bleach and meat in it. It looked like they had been bleaching poultry to make it look fresher.’’
Sarah Appleby from the Food Standards Agency added: "This criminal activity could have put many lives at risk.’’
Defending Yakub Yusuf, Kitty Taylor said: "He will have to rebuild not only his own life but that of his family. He has a wife and two children.
"He will have to find a way to make a living in the future and that will not be helped by the probation order preventing him from working in the food industry.’’
Sentencing the three men, Judge Paul Hoffman said: "This plant was set up to serve the large Asian population with halal meat. It was a substantial business.
"Sales could have been up to half a million pounds, though it doesn’t matter if the sales were £200,000 or £500,000 pounds, the point is it was a substantial operation and sales were all over West and South Yorkshire.
"It is the potential of food poisoning which is so alarming. Though no-one was harmed, the potential is a very aggravating feature of this case. The potential impact on your fellow people cannot be too highly stated.’’
Judge Hoffman sentenced Yakub Yusuf to four and a half years imprisonment for his part in the plant and Ibrahim Yusuf, who is already serving a sentence of three and a half years, to a further 30 months.
Nabil Allibou was given a 24 week prison sentence suspended for two years and a community order of 100 hours.
The brothers admitted putting animal products on the market without identification, failing to ensure premises and equipment were clean, storing cleaning agents where food was handled, leaving meat exposed, failing to provide adequate changing facilities for staff, failing to provide hand-washing facilities and failing to provide facilities for disinfecting tools.