Seriously?
The whole fecking thing was staged!
I saw soap powder, various other boxed and canned products but no 'fresh produce' - I may have had my eyes shut from pissing myself laughing - but the producers set these things up!
It wasn't even in a real supermarket FFS! You can hardly get a trolley round a supermarket, never mind a Golf GTI! 
At least not the ones here!
We all know that thousands of supermarkets each and every day chuck tonnes of food out. FACT
But they are getting more aware of how to reduce waste. Top Gear is not your beef here OP......
There is no excuse for it, they could pass it onto food banks, something that I personally donate to each week when I see we have something coming close to it's 'use by' date.
Top Gear is a fave in this house, a bunch of middle aged men, who should know better, rolling a Nova in a field, driving in an orange velvet golf and having a reet laugh..... isn't all about taking things a bit less seriously sometimes? Just for an hour?
If you don't approve, don't watch it. :)