The plastic is a very understandable thing...it's a manufacturing environment, machine break, pieces may go flying. A small piece could break off and the equipment may still be functioning so it goes unnoticed. This kind of stuff happens all the time, I remember my grandmother finding glass in a can of corn and that was probably 40 years ago. One incident does not make a pattern.
As for the nails, I find the story pretty suspicious...the dog food supposedly had nails in it, yet they report it to Petco, send a letter to Merrick and wait for a response. Nothing mentioned about taking the dog to the vet. If it were my dog, that's the first thing I'm doing...nails show up very nicely on x-rays. Then to top it off...they throw the product away. I assume the bag went with it so now there's no lot code info for any traceability.
I do agree that they should have been more responsive than they were.
Now if you want something to be concerned about with Merrick...I'd be more concerned about the several dog treat recalls they've had in the last few years for salmonella.
Holly, Misty & their friend, Jake, the dog.
Onyx, Callie May, Maggie & Kobi forever in my heart.
Yes, I know I need a new signature pic...someday...