Sand/stone like pieces in viennas

I have been a fan of simply chicken viennas for a long time but lately every time I have a vienna it seems to have chips of stones or something similar in every other bite. I'm sure other people have felt it too. I thought something was wrong with me and asked my family members to taste it and they confirmed they could taste the bits of sand or stone as well. It really puts me off from buying this product again. I hope others that have experienced this can relate to this. It makes me wonder what's going into this product lately. Is the equipment used being cleaned properly? Is anyone testing the products?