Jan, if listeria is in the food consumed, it doesn't matter about the qty persea. If you ate the salad for lunch I would imagine you would know about it by now. Remember, that just because a food is a "risk" for listeria doesn't mean it is going to be contaminated or that you will be affected. I know it's easier said than done, but try not to stress about it. If you do feel that you have symptoms, pop down to your local A&E and explain it to them, they will help treat it and keep things on track. Or give your health care provider a call in the morning.

MG