Not watching but am guessing it's lifting lid on generally unhygenic shannanigans in various restaurants and chains?
When I was 17 I worked in a pizza 'restaurant' and we got up to allsorts in the kitchens whilst the manager was front of house - spraying squirty cream in each other's mouths; putting pizza dough on our faces and chasing round the kitchen, then putting the dough back in the pizza pans for cooking; very often picking up food we'd dropped off the floor and serving it... kids, eh?
Well it showed them dropping chickens on the floor and then cooking them, leaving stuff out of a fridge for 4 hours and then suggesting it be put out in the rain cos there was no space in the kitchen, general dirtiness and cross contamination. I don't think our harvester is guilty of any of this though.
Then it showed them refilling the salad without emptying and washing out the container or using a clean one and having a slippy floor. Both of these are pretty standard where I work. There was a bug found in the salad which I can also recall happening at least once.
I have seen people reuse dropped cutlery and wash glasses out under the hot tap when we've run out on thwe bar and haven't got time to put them through the dishwasher. The fridges on our bar were broken for ages and we used bottle bins filled up with ice. I have also known of the odd complaints of hair and plastic being in food. Oh and once we apparently served a gone off steak but not sure if that was true. Other people ate steak out of the same pack afterwards without complaint. Oh and once we had to put sauces in containers of ice on the salad cart cos it was broken.