Published by the Public Health Protection Unit of NHS Greater Glasgow and Clyde, the report said that 19 of the cases ate beef burgers at the Big Grill  at SSE Hydro between 17 and 19 January, 2013. The remaining three individuals, all female, were “household contacts of these primary cases.”

The report said that the investigation uncovered evidence “strongly suggesting the possibility of processing errors leading to undercooking as well as the potential for cross contamination in the preparation and serving of the beef burger products.

The report also found that in the preparation of the burgers the searing of the meat was uneven, with some appearing to be well-seared while others “were barely seared with pink raw meat visible on the surface of the burger.”

Inspectors observed inadequacy of temperature monitoring records and weaknesses in temperature monitoring of food to test how cooked items were by staff.

It was also discovered there was “an inappropriate cleaning and disinfection regime, and an absence of documented evidence of a hazard analysis” at the venue.