Go into one of your chef's/staff's mysterious items box. Press CTRL+ALT+A and you'll get 1 of each of the mysterious items in the game. Continue holding CTRL+ALT and pressing A to receive many items.
Various Codes
Enter one of the following codes during game play to activate the corresponding cheat function.
Effect
Code
$100,000
[Shift] + [Alt] + C
Toggle exterior upgrade for all restaurants
[Alt] + [Ctrl] + E
Raise ingredients and food rating
[Shift] + [Alt] + F
Win scenario
Press [F11] during game play, then press [Shift] + [Alt] + V.