William Tudor from Crowbridge, Vale of Glamorgan, initially pleaded not guilty to 12 charges bought against him by Caerphilly, Rhondda Cynon Taf Council and Bridgend Councils.
But last week he admitted to six counts, at Cardiff Crown Court, which related to meat originating from his premises to schools on two days in September 2005.
One of the charges involved supplying contaminated meat to Deri primary school in Bargoed, Rhymney Valley. Mason Jones, the only person to die in the outbreak, was a pupil.
The other charges involve five other junior and primary schools in the south Wales valleys.
Tudor pleaded guilty to charges under the general food regulations of placing unsafe food on the market. The prosecution was brought by Rhondda Cynon Taff and Caerphilly Councils.
It remains to be seen what Tudor's plea will be to the six counts relating to the condition of his Bridgend premises, a prosecution brought by Bridgend Counci when he is back in court next Friday.