Hey SS Sorry for the delay in replying. I dont frequent the site as much these days. I think I've gone full circle now and find it generally less interesting as most of the topics raised have been discussed before. In answer to your reply; The Chinese have a saying " If it has lived...then you can eat it" but they dont specify a timescale lol!
I know what you mean about not being able to disguise the quality of the veg but sometimes poor quality produce (Im thinking in terms of potatoes mainly) are sold to the catering trade in the form of outgrades / peelers. These are essentially a good spud with a blemish/mark on that can be removed with a knife after they have been through the rumbler. The final quality of the produce is not compromised, it just takes more prepping to get there and a little bit more waste. As far as Chinese Restaurants go on the potato front: they seem to prefer to buy the frozen par-fried chips. My Asian wholesaler friend tells me (and has confirmed it to me again today) that he can usually shift onions that have started to shoot a bit to the chinese restaurants. He does have to occasionally dump a few though that he cant sell.
If you think about tomatoes: the riper they are the sweeter they are so it follows that if they buy a box of toms that are past their "best by" date there a probably a few casualties in the box but the good ones will be very good - if you know what I mean?
I would also add that the "posher places" would possibly buy better produce two of three times a week direct from their local wholesale market