In The PC Game Ratatouille, How Do I Pick Up Pices Of Cheese?

The pieces of cheese are for your health bar. Each piece is one health bar/piece. You only truly pick them up when you are at less than full health. You'll know you were at less than 100% health and you picked up a cheese when you hear a munching noise and Remy ate the cheese. Otherwise, the cheese will just fade for a few seconds and reappear. This means Remy is at full health and doesn't need any cheese.