Canon Pro USB Legacy- Edible Printing System

Q: I'm so glad that I've seen your site about using these Canon Endurance printers. I can't purchase the printer from you as I'm in Australia but have bookmarked for your other items! I just have a quick question - I have this printer - new in the box - and I put some edible ink and it's printing beautifully - my question is the little cartridges that you insert into the middle of the printer - is there anything in those - eg; ink or anything else - or are they simply used to feed the edible ink through? Im just so nervous about using the printer for my customers (I've been using the CAnon ix 6860 for the past 6 years) Thanks in advance for your reply - just don't want to poison anyone!