When I went to TJ Mexico a couple of times in the early 70’s I stayed away from the ‘Tourista’ places and went to small, out of the way, restaurants. Never, ever got sick..............
When I lived and taught in a town on the Yucatan for awhile, I ate food from street vendors all the time and never got sick. The locals pointed out to me which ones were “safe” and which were not.
There was this sweet old lady who sold fresh raw jicama slices with lime and chili sprinkles that were so yummy and refreshing on a hot day. Very dicey food choice if you go to a careless vendor, though, so I would not recommend it.