Batch cooking/making up food

[smileyhappypeople]

Sooo.... While trying to be super organised and get on top of things I've found myself watching people organise their fridges etc on YouTube (sad, I know!)
Anyway, quite a few ladies were making up snack bags for their children and things like salads....
I thought it was a great idea as I often find myself telling the kids just to grab a biscuit or whatever because I haven't got time can't be bothered to prep some fruit.
My problem is how on earth does she make chopped grapes and salad items like tomatoes and cucumber last 7 days??
One lady also made up granola, yoghurt and fruit.... Again, surely that won't last??
Sooo what are your tips for making food last?? And what do you prep in advance that makes a great snack/quick lunch.
Also for dinner, I don't mind cooking the main ingredient but would love to cook up/portion some nice and easy side dishes.