So far we’ve been assuming you’re outside a city. However, if you’re in an urban disaster situation, it might take some time and effort to get to a safe place where you can be more self-sufficient. Meanwhile, you have yourself and your family to feed.
Your best bet is to start with the homes of people who have just left. They will have taken everything they can fit in their vehicle or on their backs. That means you’re going to be left with a miscellaneous collection of things they couldn’t fit and found a low priority – but you won’t have to fight for them and you’ll be able to rest easy knowing you’re not taking anything the owners deemed necessary for survival.
Treat the house like you hope others would treat yours. Hopefully, the owners will be able to come back some day. Unplug the fridge and leave both the refrigerator and freezer open. That way, if the power does come back they won’t suddenly be chilling rotten food, which would leave their refrigerator unusable in the future. It also clearly demonstrates to other looters that there’s nothing to eat. Likewise, leave all the barren cabinets wide open so people who come after you can see there isn’t any food. This reduces the likelihood that looters will destroy the place as they search. Go ahead and take whatever food you can find, even if it seems completely useless to your needs. Someone is likely to want it, and when you meet them, you can negotiate a trade.