Hi RAL -- I'm sorry, I don't know how to figure out what you've missed, short of replaying the game myself and taking notes! I can't go back in and look at things because of the autosave feature, now that I've finished the game. At least, I don't think I can. I'll check it.
EDIT: Yes, I can't go back to my previous game, so I'm having to start over. From scratch.
EDIT AGAIN: I've replayed to the point where the line in the casebook that says "Find the food" gets crossed out.
In the evidence folder everything that seems to be related to food is:
The knife with butter on it (near the bread). The butter (in the large rectangular chest in front of the bike). These two need to be linked in the evidence folder.
Everything else I think you've found, RAL -- the bread, the chutney, the pickles, the ham and the salt grinder.
I did run into a few other things that were technically related to food -- empty bottles, a decanter, a coffee urn, and a wine rack, but the game didn't place them in the evidence folder, so I don't think they're important.