Well, in my experience, often the food bag is sealed with a tamper proof seal on it. I had the same fears as well, but then I did some mystery shop evaluations for Door Dash and Uber Eats where they paid me plus food reimbursement to test out the service and I found that the foods were indeed delivered tamper proof.
The same cannot be said for most pizza deliveries. In fact, I remember when my DH and I were traveling once and got into a hotel late on our route, and the only thing available to order delivered was pizza. We ordered a pepperoni and mushroom pizza, and when the pizza arrived, we could see the bare spots where the pepperonis had been (I think there were only about 6 left on a large pizza), and my DH found a half eaten pepperoni on the elevator floor later when he went down to the car to get something. We had heated it in the in-room microwave so not too concerned about pathogens, but still we were not happy about it.
My wife won’t budge on it. If she is home and we order a pizza, she goes and picks it up. And will only go to one place. It’s a restaurant that makes pizza, pasta dishes mainly. Kind of a gastropub. The woman that is the manager went to school with our daughters. She trusts her. We went one night and she wasn’t there. My wife wanted to leave. She had really bad teeth as a child and got bullied bad. Maybe somebody did something to her food during that time.