No, yes, no, and yes. I would keep the items that could be washed and throw away those that can’t be.
I’d assume that the store wouldn’t ask me to pay for a bulk item that I’d dropped, but I’d tell an employee that I’d dropped it. If the store did expect me to pay for it, I’d do so and then I’d probably never shop there again because I know there are stores who actually care about customer service nearby. Come to think of it, I often spill a little flour or oats or beans when I’m trying to scoop them into a bag at the Whole Foods; I’ve always told an employee and apologized for the mess, but if the store finds it inefficient to eat the cost of the product that spills, they should consider doing away with self-service.
So, if an employee was bagging your bagel and dropped it, would you feel the store was within its rights to take the price out of his salary?
I’m not making an ethical argument, but rather pointing out what the convention is. To simply consider the question in the OP at face value, “Was I supposed to pay for it?”, the answer (according to usual business practices in the United States of America in 2013) is a clear “No.” The expectation by most businesses (at least those dealing in food and other perishable goods) is that they will absorb the cost of goods inadvertently damaged by customers. There may be some businesses that don’t follow that convention, but they are in the minority. (On the other hand, businesses that deal in durable goods like gift shops follow the convention “You break it you’ve bought it,” which is fine too.)
You’re addressing a question different from that in the OP, which seems to be what the ethical obligation should be. The ethical obligation may well be different from business practice, which is to give the advantage to the customer.