Garrghh — what's that awful smell?

As you scan the office fridge for culprits, your brain tries to identify the stench. Moldy potato salad? Salami gone bad? It might have something to do with that brownish mystery juice, but who knows where that came from.

The bigger your office, it seems, the more likely your fridge will become a dumping ground for smelly and unpleasant-looking leftovers.

"After a while people hate to put their own food in because there's so much ... stuff in there," said Alice Henneman, extension educator at the University of Nebraska-Lincoln, who studies these things. "Some of it gets really gross."

Having your Dr Pepper smell like someone's cabbage is one thing. But in some cases, a nasty office fridge has actually made employees sick.

It may have happened to you, too, though you may not realize it.

"An illness can happen anywhere from half an hour to as long as six weeks afterward," Henneman said.

The problem with office fridges isn't just aging food, Henneman said. A fridge that's opened a lot — a problem at companies with many employees — can pose a risk as well because the cool air escapes and a safe temperature isn't maintained.

Lunches should also be removed after three days.

At PG&E's community center in San Luis Obispo, Calif., food gets left behind not only by employees, but also by nonprofit groups that meet there.

"Sometimes they don't walk off with the cake or cold cuts or whatever," said spokeswoman Sharon Gavin. "They get left in our refrigerator."

Yet, the fridge manages to stay clean — partly because the staff at that office is small, fewer than 10 people — and because an administrative assistant is assigned to keep tabs on the icebox.

"We probably clean the refrigerator once a week because anything older has a potential of being stinky over the weekend," she said.

Here are some tips for food safety