What are some practical food waste reduction systems?

I (24) live at home with my parents and adult brother. We all do our own food shopping, and some things we buy overlap (like bananas), other things are totally different (I eat brown, sourdough bread, my parents like the white toastie bread), my parents eat ham, I hate it, my brother likes frozen food. It gets to the point where the things we buy that overlap, like bananas, end up going mouldy - I don't want to just rely on my parents, because sometimes my dad will eat three bananas in a day, or they feed them to the grandkids (not my children, obviously). I've just had to get rid of a bag and a half of food from the fridge and freezer that was either mouldy or covered in freezer burn and ice. What can we actually do that's practical? I work a 9-5:30, my brother works antisocial hours, my dad is retired and my mum works part time - so we're all really split up, so going to do a food shop all together doesn't work. We all feel awful about wasting so much though, so what are some things to reduce this waste that actually work?