Based on most media stories I’ve seen on the issue the majority of dead rodents or similar ex-living things in sealed or prepared food claims are usually a result of consumer fraud.
In general I think the onus would be on the claimant to prove they did not do this themselves and adulteration happened at the factory. How that would be accomplished I have no idea.
You shouldn’t put cereal in the fridge. You should put it in the freezer for at least 48 hours, just in case it has some many-legged hitchhikers in it.
Living in California myself, I can tell you that the logic a court would use in a case like this is that the ‘victim’ (and they will almost surely be called this) may have an irrational phobia of rats, be allergic to their dander, etc. and the ‘damages’ may be difficult to calculate. In some cases, perhaps you can point to real out-of-pocket costs of the damage, such as therapy, lost wages from depression or anxiety, and associated drugs. In other cases, you could point to a general loss of quality of life, which is to say the person can no longer eat cereal without getting nauseous, but that’s just it. How do you explain the fact one person is horrified by something other’s aren’t. I once found what was either a piece of bone or rock in a taco at Taco Bell, which I found while eating at the restaurant in full view of the cashier. They immediately offered me a new taco, which was all I really wanted, and I still eat there to this day. Some people might have freaked out about it, but I didn’t care. In fact, I just had Taco Bell again the other day…
Dead rat in a cereal box? Pretty far fetched. But a dead bird? That can and does happen: http://www.youtube. com/watch?v=Sw7RxrozfO4
(Link broken for NSFW but understandable language, remove the space before ‘com’)