The law is basically that if there was a 'foreign substance" in the food, then the seller did 2 things wrong: 1) breached the contract for which you paid money to receive something safe and edible, and 2) breached the warranty that the food product was fit for the purpose intended. So, if you bought a piece of cherry pie and bit into it, and found a cherry pit, there would be no case, because cherries have pits. However, if you found a rock, then there would be a case because rocks have no connection with cherry pit. In your case, if you had a fish sandwich and found a fish bone, no case. However, if you found a bone from beef, ham, etc., then there would be a case.
Answered on May 10th, 2013 at 5:43 AM