As soon as you slice tomatoes, onions, green peppers, and mushrooms they begin to breakdown, the oxygen has a funny way of screwing that up.
Your product life on veggies is about 2 to 3 weeks uncut, once you cut them you might get a week, if you are buying them pre-cut, how many days are they sitting in your suppliers refer, before they deliver them to you, what is the usefull life of the product after you receive it three, maybe four days.
When I worked for Dominos we got pre-cut veggies, and unfortunately we sold alot of crappy pizza with green peppers that had completely broken down. If you were at the end of a delivery line sometimes your veggies would come in frozen, when they thawed they turned to mush.
Dominos tried some herb pizza back in the 90’s, and they deliver frozen pre-cut red, yellow, and green peppers in a bag, when they thawed it was like scooping mush onto a pizza, what a fiasco.
I went to work for Papa John’s for a year before starting my own chain, and I really respect their fresh veggie mentality. We would pre-cut veggie everyday. The only thing we got pre-cut was the fresh mushrooms, its much easier and much more uniform.
Also once you cut a onion, green pepper, or tomato the cellular wall of the veggie begins to breakdown, the longer they sit the more moisture they let go of when their cooked. Ever seen the bottom of a pizza pox that was really wet? This is why?