I always worry about the homemade pesto.

The culprit in the Celtic Park salmonella outbreak was probably a dodgy ham and mozzarella salad, a report has revealed.

Nineteen guests at the Glasgow ground were struck down with vomiting and diarrhea last September.

Despite initial suggestions that a lamb dish was the chief suspect, months of sophisticated testing have pointed towards an Italian delicacy.

The investigation by the public health protection unit of NHS Greater Glasgow and Clyde (NHSGGC) found that all those struck down had the starter of “prosciutto ham, mozzarella, and home-made pesto dressing”.

Two people were admitted to hospital following the outbreak but all the victims made a full recovery.

It is believed they were all at the ground for either the Celtic v Motherwell game on Sunday 21st September, or the Celtic v Hearts game three days later.

Investigators carried out an assessment of the food-making process for each component of the starter, even down to the draining of the mozzarella balls.

But it was impossible to test the actual ingredients used in the starters because they had all either been eaten or thrown away.