Hi Cathleen, and welcome. I am a licensed attorney and happy to assist.
I'm sorry to hear of the situation, and grateful to learn that you noticed the issue before consumption. Strange items in products are not unheard of, and I know of a situation in which a large metal bold was found inside an ice cream bar, after the consumer bit into it. You made a wise choice to allow photographs, but not turn over the actual product.
From a legal perspective, this is a product liability issue, for which both the manufacturer and the seller of the product are equally liable for any damages incurred. While it is not necessarily the seller's fault, the law provides that liability is equally shared. In the event the store is sued for liability that store would simply counterclaim for indemnification against the manufacturer and all would work out equitably. The key to Legal damages is that a court will only make an award if actual damages physical damage was incurred. As an example, such would be the case if you had swallowed some or all of the plastic part, requiring emergency medical assistance, surgery, and perhaps lifesaving measures at a local hospital.Thankfully, you avoided what could have been a deadly ordeal before it fully developed. The flipside of that, is that a court of law would deny you compensation, despite the obvious problem that occurred in the manufacturing process. That said, manufacturers often want to avoid the cost of having to go through the process of litigation and, upon receipt of a demand letter, they often offer to pay a small sum to make the matter go away, even in instances were no physical injury was incurred. This makes sense, since it is in the company's financial best interest, both in avoiding potential litigation hassles and maintaining business good will.
The key here is to contact the company's legal department with a demand letter, attaching relevant photographs, the report taken by the store (if they agree to provide you with a copy) and any other evidence you potentially have. Chances are you will receive a timely response, though not likely any admission of fault. In the case I initially mentioned with the bolt, a check for $250 was included in the response. Since there was no physical harm to the child who unexpectedly found a large metal bolt in her mouth, the check was accepted and cashed as the best possible legal outcome. It was an acceptable outcome for the family and also alerted the company to a problem that they hopefully corrected to avoid injury to others.
If you decide to contact the company directly, you can contact ConAgra Foods (Banquet Pot Pie manufacturer) directly at(###) ###-#### They are in Washington an d will provide you with an address and phone number for their risk/legal department to which product defect claims may be made.
I wish I could tell you to expect a written apology (you won't get one for legal reasons) or a big check for the outrageous finding, but having accurate information allows you to make informed decisions going forward and will save you much time, money, and emotional energy in the long run.
I hope this helps. If you need additional information or clarification, please let me know and I will continue providing assistance. If I have addressed your concerns or pointed you in a positive direction, please remember to leave a positive rating when prompted, as that is how attorneys on this site are credited for the help we provide.
Good luck and be well.