Given that dogs, digestive-wise, unless there's something abnormal going on or allergies, are pretty much flightless buzzards with fur, I wouldn't stress too much about it.
Mine have gotten into shrimp shells in the garbage more often than I care to remember. They love them, and will get them within a nanosecond, no matter how well wrapped and how far down they are
It's like trying to keep someone with the munchies away from the Doritos.