<<Disclaimer: Verify this information before applying it to your situation.>>

Here's a summary to several questions about citric acid in jam, as well
as cheese in general and chocolate in general.

I got 17 useful responses.

Citric Acid:
I was told that citric acid manufactured in the US is GF, but outside of
the US it can have a wheat base. Even products manufactured within the
US may use imported citric acid, so it's best to check.

Cheese:
I was told that processed cheese can contain gluten.  Also, shredded
cheese is often dusted with flour to stop it from sticking together.
Some people are concerned about annatto colouring in cheese, but most
said they feel it is safe. One person said many cheeses contain gluten
as a stabilizer, which I highly doubt, as it would be indicated. Block
cheese is considered safe by almost everyone. Bleu cheeses should be
avoided because the mold is produced from bread.

Chocolate:
Chocolate candies may be dusted with flour to stop them sticking, but
most candy bars are considered safe (as long as there is no obvious
gluten, such as cookie crubms etc). Chocolate processed with alkali may
not be safe, but there was no reason given. Some people are wary of
vanilla and vanillin in chocolate. Most Hershey chocolate bars in the US
are GF, and all LINDT chocolate is manufactured in a GF facotry,
according to one person.

Thanks everyone.

Kate in Montreal