Z-Bizkuits is a cookie originated in a bakery in Canada, after a recipe by a woman named Marion, it was invented after one of her sons became a Talker. She has since then made more and distribute them to Altura, Pacifica and Limbo in order to keep the Talkers from turning.
The Z-Bizkuits are fed to recently turned humans to keep them from turning full zombie. They are descirbed as to have a metallic taste according to the Talkers. They are rumoured to have trace amounts of brains in them.
According to Marion the first few batches she made had brains. But as they were not so easy to come by, she then managed to replace the brains with a secret ingredients, something that later turns out to be Lithium.