Bio-Hazard Body part in MacDonalds Salad

The other night a little after 9:30pm I took my friend to MacDonalds to try the new Asian Salad. We purchased our food and brought it home. When she began chewing the first bite of her salad she spit out a fingernail, not just a clipping but a long dirty finger nail (3/8" or better), like the dopers have.
My friend of course felt like puking and since then, everytime the thought of the incident comes to mind.
We took the salad and the disgusting added munchie in a ziplock bag back into MacDonalds the next morning so the Manager could see it and investigate whom it came from. (MacDonalds salads are prepared within 8 hours of serving, so they claim.)
She looked at it for a few mins and said she would investigate. Of course we never heard from her again.
A couple of days later I called the corporate offices of MacDonalds and related the story to them. They took it a little more seriously. Since then we have had calls from the District Manager, their liability Attys and a meeting with the DM at the store to verify it really is a fingernail.
It naturally grossed him out as well and he immediately confirmed it to be someones fingernail. He stated the Liability Attys had requested he confirm the object and report his findings back to them. He stated he would do this the next morning(today).
We donot want coupons for more salads, what we do want is to know where this came from and the health risks associated with it.
There were no physical injurys other than biting down on it but there will obviously be mental anguish until the matter is resolved.
MacDonalds wants to know if we have contacted an atty or if we plan on suing.
Does anyone have any recommended input for this situation?
Thanks!

I am anti "I found .... in my food." Damages are typically nill and companys typically offer free food etc. So my best advice is to contact an attorney in your area who can tell you what he/she thinks of your case.

LOL, No way I believe you'd eat that salad!
Thanks for your suggestion

You're probably right...I am jaded from the whole finger in the chili.