Jimmy, Kate and Matt ask how much cow is in a beef stock cube, how cornflakes are made, and what exactly processed cheese is. Jimmy tests stock - homemade versus a cube - and is surprised to learn that a cube isn't made the traditional way, from boiled bones. So what is the 'beef extract' referred to on the label? Jimmy heads to Brazil, to a company which produces a quarter of the beef that is consumed globally each year, to find out more about this mysterious ingredient. Iron is essential to the human body, carrying oxygen through the blood, but what does it look like? And why is it added to cornflakes? Processed cheese doesn't come in chunks or blocks but melts nicely all over a burger, so what's in it? Matt helps to make one and is shocked to learn that there could be as little as 10 per cent cheese in each slice and that it's even possible to make a yellow cheese-style slice with no cheese at all.