Guys, it is complicated, and there are "conflicting" bits of information becasue of the time and number of processes that go on between raw food and the food that goes in your mouth.

With regard to cold cooked prawns or cold cooked anything the problem is that the time it takes food that has been cooked to cool down is quite long and do you know how it has been stored whilst it is cooling?

ie You cook some raw prawns on the bbq , then take them off the BBQ and leave them "to cool" on a plate whilst you cook the snags and have a gossip.........those prawns are coming back down to an ambient temp VERY slowly, in the open air, so I would NOT risk those prawns.

However, if you are cooking prawns in your kitchen, and as soon as they are cooked you devein them &put them on a clean plate at the back of the fridge, covered, they will go cold quickly, so these would be regarded as safe.

Same with cold chicken. For example, if you bought a cooked BBQ chook at Woolies and it was "cooling down" in the car and then you get home, unpack the shopping and put the chicken away, then I wouldn't risk this (not from a Listeria perspective, but from a Salmonella perspective.)

If however, you cook some chicken breasts to a very high temp in the oven, and then as soon as they are cooked put them covered in the fridge, then shred the meat for sandwhiches the next day, this would not be a risk.

I guess the best rule of thumb, and one that I follow, is, IF YOU ARE UNSURE, DON'T RISK IT!