When packing for your holidays, bringing along your hairdryer might not seem important.

After all, they're one of  the essential items usually supplied by hotels once you arrive. But you might be better off to make a bit more room in your luggage so you can bring the appliance along. A previous investigation by ABC News found some pretty grim truths about the hairdryers in hotels. Microbiologist Chuck Gerba tested nine hotels between three stars and five stars in the Los Angeles area - and was pretty unimpressed with what he found. He said: “There must be some things you can do with a hair dryer that I am not aware of because some of them were pretty germy.” The investigation notes that things like hair dryers might be even dirtier than toilets and sinks in the hotel because they can sometimes be overlooked when it comes time to clean the bathroom. Other items in hotel rooms that are frequently touched but might not always seem obviously "germy" are things like kettles, light switches and the room service menu. Chuck added:

"You have to be very careful in the use of your disinfectants, your cleaning tools, and where you wipe and what you wipe so you don't really move germs around. "You don't want to give them a free ride around the hotel room."

So the next time you're heading on vacation, you may just want make a bit more space in the suitcase for your hairdryer.