There are two ways to hang toilet paper: 1) over (with the loose end draped over the top) and 2) under (with the loose end hanging inside next to the wall). Most offices hang it "over" but I've been in many restrooms where it's been hung "under."

The over/under issue is surprisingly controversial and was allegedly the topic that generated the most letters to Dear Abby on a single subject. I'm here today to remove that controversy forever.

According to science, the correct way to hang toilet paper is "over." Why? Because "under" vastly increases the possibility that food-poisoning bacteria will spread from the restroom to the rest of the workplace.

A recent study conducted at the University of Colorado revealed that even an apparently clean office restroom is a dirty Petri dish:

"Using a high-tech genetic sequencing tool, researchers identified 19 groups of bacteria on the doors, floors, faucet handles, soap dispensers, and toilets of 12 public restrooms in Colorado -- six men's restrooms and six women's restrooms. Many of the bacteria strains identified could be transmitted by touching contaminated surfaces."

Much of bacteria found in public restrooms is e. coli from human feces, a common source of food poisoning. E-coli is easily transferred from surfaces to your fingers and thence to anything that you eat with your hands.

Which brings us to hanging toilet paper. The moment when a restroom user's hands are most likely to carry bacteria is when they reach for toilet paper.

If the toilet paper is hung "over" their fingers only touch the toilet paper that they'll be using, which will subsequently be flushed.

However, if the toilet paper is hung "under" there's a good chance their fingers will brush the wall as well, leaving a deposit.

If so, every subsequent restroom user who reaches for toilet paper runs the risk of not only of picking up the bacteria that's been deposited already, but also leaving more for the next user to pick up.

Just as important, the "under" hang--and subsequent likelihood of touching the wall--also makes it more difficult to use a scrap of toilet paper to keep from directly touching the toilet seat, flush handle and stall lock without getting bacteria from the wall on your hand.

Once bacteria is on your hand, it's damned difficult to remove. The way most people wash their hands--a couple of seconds with a dab of soap--is useless. To get your hands thoroughly clean, you must scrub with lather for at least 20 seconds, which is roughly the time it takes to sing "happy birthday" twice at normal speed.

If you follow that rule, great, but let it be known you're the minority. Most people do a crappy job at hand-washing and if you're in an office of any size, I can almost guarantee you that some of your coworkers are skipping it entirely.

And then reaching into the box of donuts in the break room.

If you've never had food poisoning, here's what it's like. Imagine the worst flu you've ever experienced (nausea, vomiting, diarrhea, weakness, etc.) and multiply it times ten. I once had food poisoning with my wife and we were so weak that we were literally unable to get out of bed for 12 hours.

When food poisoning happens at work (and it happens with surprising frequency), it can hit big. In an office in Maitland, Florida, for example, food poisoning struck 55 employees, 25 of which ended up being hospitalized. The likely culprit according to local authorities: "improper hand washing." (Surprise!)

Beyond the obvious productivity hit of dozens of employees out sick, you, as an employer, can be held liable for food poisoning in the workplace. Poisoned employees can apply for worker's comp and, depending on circumstance, can bring a lawsuit against you.

And that's not joke, because while most victims of food poisoning recover within 24 hours, in the worst cases, food poisoning can result in brain damage and even death.