The pizza sauce contain beef stock.

So if you eat there ask for your pizza to be made with marinara sauce instead.

I am surprised they do not post that beef stock is in the pizza sauce.

Wow, I never thought about something like that! I guess that goes to show how easily animal products can be hidden in restaurant foods. Yuck

Also in Mexican restaurants the rice often is made with chicken broth.

As careful as you try to be, anyone who eats out at restaurants that aren't exclusively veg*n restaurants is likely consuming at least trace amounts of animal products unintentionally. It sucks, but that’s unfortunately how it is. Even if you ask your server specifically if something is vegetarian they may not be thinking about things like gelatin, animal rennet, meat stocks is soups and sauces, etc. Back in college I used to eat at a Cornish pasty place that had an item called the "veggie weggie", turns out they used lard in all their crusts so nothing there was vegetarian.