If you are referring to cross contamination then yes you can.
Veg has differn't forms of bacteria on it to fruit. If you do not wash it correctly before preping it then the chemicals it is grown in can remain.As long as you wash implements between prepping the two you should be ok.
I only know this because i used to get yelled at for not washing between doing the two!!
the reason you have to wash fruit and veg is that the food pickers are outside all day picking fruit and veg and when they go to the toilet sometimes outside they dont wash there hands also there are pesticides on them as well.
some farmers have been known to spray there crops with sewage water during droughts so this is why it must be washed hope i didnt put you off.