I used to work in catering for a national organisation. Each site had a different offer depending on its size and footfall, and we had to maintain this par level of food at all times, regardless of local knowledge. We were expected to have some wastage at the end of each day. Only after the first month when there was £56000 worth of wastage across the company did they acknowledge that perhaps the par should be set by each site, and be a little bit flexible. Still in catering but not at the same place, I feel that one of the major contributory factors to wastage is caused by inflexibility in areas such as procurement- for example we have to buy from particular suppliers, who may only supply certain ingredients in large quantities which then are out of date before they can be fully used, and inflexibility in use by dates themselves. There are lots of burgeoning organisations appearing, some of which purportedly are backed by the big chains, which are now championing the idea of not wasting food, and there are shops and restaurants opening which deal solely in past-sell-by-date produce, but it's not just a case of freezing leftovers, it needs to be addressed from both sides of the market - the sellers and the consumers need to be educated in sustainability and seasonality - it affects everyone, and can be addressed by everyone.
Unfortunately there is a lot of education needed - I won't mention my current gripes - that would be unprofessional, but I met a 20 year old recently who'd never peeled an apple, and in a slightly related anecdote, years ago I heard a parent say that her family had a balanced diet - fish and chips on Monday, Wednesday and Friday, and burgers on the other days - all of them local because they only had to drive round the corner to fetch them.