About 60 people were struck down by the potentially deadly bug in Leeds in 2006 - one of Yorkshire's worse E.coli outbreaks - which led to the investigtion of Todd's Pork and Beef Butchers, in Armley.
The firm was fined this week at Leeds Magistrates Court to £20,000 after admitting four charges relating to breaches of hygiene practices. The most serious charge was that it placed on the market cooked meat which was contaminated with E.coli.
A director at the firm, William Munro, 52, of Escourt Road, Darrington, was facing charges relating to breaches of hygiene but they were withdrawn.
The court heard environmental health officers were led to the butcher's shop after two victims said they bought meat there.
They found "greasy, thick black deposits of food" and what appeared to be dried blood on a door handle, as well as dust and cobwebs above missing ceiling tiles.
An officer also witnessed a staff member with their arms covered in scraps of raw meat and blood, walk from a raw meat preparation room into the cooked meat slicing room.
Swabs taken at the shop did not detect E.coli but it was found on cooked beef at Todd's stall in Kirkgate Market, Leeds.
The court was told that Leeds Council could not prove beyond resaonsble doubt a causal link between the outbreak and the offences admitted.
John Goulding, mitigating for the company - which also operated as WT and C Munro, said the investigation into Todd's had caused "financial ruin", the shop and closed and not reopened.
He added: "The directors had to sell their houses to pay business loads; they now rent accommodation. Hitherto the company was of good character."
He said the sentencing excercise was "academic" because they would not be able to pay the fine.