If the vegetable broth from the tuna had wheat, they would be required to list that.
I don't see any reason the tuna or the plain ground beef would have gluten. Its possible, if it came from a meat counter that something from another meat product fell in the hamburger. Like some breading if they sell breaded cutlets in the same open case.
Sometimes, when you are new to the diet, you can either miss something that is glutening you or your insides are so damaged something else bothersyou. For example, ground beef is very fatty and that can be hard for some people. You might have rinsed the fruit in a colander that you used for gluten pasta, etc, etc, etc.
