Under the Tab "The Gravy Jar"
This sounds vaguely like something I've read before, but I can't find any article for it as of yet, so I'll ignore that for now. Material transmutation has been done before, but not in a food context.
I don't really care for the premise. If something's anomalous, they won't test it on staff, unless there is no alternative. Even if conclusively proven to be safe.
The item itself is OK, if not very interesting, and the test logs are sort of amusing. Significant tone issues. It's not really important to note reaction unless it's scientifically relevant. For example, the D-class allergic to almonds who suffocated - that's important. The scientist reacting to sour - not important.
The refilling properties are mentioned but never expanded. We do have a couple SCPs that act like that, but that's almost more anomalous than the taste thing.
Couple scientific inaccuracies. Uranium, while radioactive - isn't THAT radioactive. In order to be lethal that quickly upon consumption would bathe the entire area in radiation. You'll either have to have a particularly active source, or settle for a slower death.
Slow-acting poison is not specific enough. Find a poison with those properties, use that as a name.
Bottom Line: The premise is out of character for the Foundation, and the item itself just isn't that interesting. Maybe with proper background, you might get somewhere. But as it stands, there's just not enough.