I think that you need to use your common sense a bit. When you're buying your food make sure that its cooked fresh and hasn't been sitting around, if it looks at all skanky or its only luke warm just avoid it. I think that you also need to avoid soft cheeses that are made from unpasturised milk. Also because heavy metals travel up the food chain its best to avoid eating large quantities of big fish like shark, tuna etc. Omega3 is really good for you and its found in fish so eating a bit is OK but its better to eat the smaller fish like whiting, bream etc.