Apparently, unless they told you, you wouldn't know. And going by technicalities, even if it's 100% beef-genetic-origin vat-grown flesh, it's still 100% real beef - even more so than 'pink slime', which means if they could kick this into high gear, McDonalds would corner the market on fast food and undercut everyone while still being able to claim 100% real beef. (Not from cows, you understand.)