It is very difficult to judge a fair settlement for a case such as this without knowng many more facts of your situation.  Generally, your daugher would have needed to suffered some physical damage as a result of the screw being in her food.  If you simply found the screw and removed it, you do not have much of a case to pursue.  If your daughter suffered an injury that required medical care as a direct result of this, then you would be entitled to her "damages" meaning the cost of her medical care and something for pain and suffering.  Without knowing all of the facts of your case, it is not possible to give you a dollar figure.  I would suggest you consult with a personal injury attorney in your area before proceeding with any type of claim.  Good luck to you.