In the past, I used to work Starbucks, there were cases where
customers in the restaurant came back to me with roaches in their
sandwiches. I was quite humiliated, but the preparation of the
sandwiches were not done by us, it was outsourced to an
external company. I talk to common folks alot, so during my chit
chat session with the delivery person, he told me that the place
that they did the preparation for the sandwiches was very
unsanitary. He even told me that those food handlers there don't
even wear shirt to prepare the sandwiches, in between the
preparation process they would strum guitar and smoke. It's a
fly by night shop, not those that operate during the day.
There waw also used plaster found in their quiche lorraine, but
this was from another external supplier.
That was in the past, since then Starbucks has changed their
food suppliers.