McDonald's plastic burger

I bought a big Mac at McDonald's in Paarl by the BP garage. Upon taking my last bite and chewing the last piece it just didn't want to break into pieces. To my finding I've been chewing on a finger piece of the plastic glove used by their staff to stack the burgers and the plastic piece was confirmed by their manager it was the finger piece specifically. Meaning I was chewing on someone's sweaty finger with my food I paid for. The manager was worse just looked at the slip acknowledged it was bought by them, took the plastic stated it is theirs then telling me to escalate it to their store manager. My number wasn't taken nothing, not even an apology. I'm disgusted that they think leaving pieces of plastic in their customers food they pay for is ok.