You make it an issue that CAN NOT be ignored by management or anyone else.
A message to all staff makes it very difficult. Tell everyone you will be removing non fridge items so you can have your lunch.
If you get a snotty one back, hit reply ALL. Honestly, it works.
As funny as this is, it now getting annoying too. Stand up to bullies. Even if they are your boss.
BCC your home email, so you have it all documented if it makes you feel better