Garrghh - what is 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 on the bottom shelf, but who knows where that came from?

The bigger your office, it seems, the more likely your fridge will become a dumping ground for meaty, smelly, and overall 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. Food needs to be kept at 40 degrees or lower to stay fresh, Henneman said.

Lunches should also be removed after three days.

At PG&E's community center in San Luis Obispo, Calif., food gets left over 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 spokesperson Sharon Gavin. "They get left in our refrigerator."

Yet, the fridge manages to stay clean - partly because the staff at that office is small, less 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.

Some tips for keeping the fridge clean and employees safe:

Refrigerated leftovers should be eaten within a day or two.

Keep your fridge at 40 degrees Fahrenheit or lower to slow bacterial growth (although freezing will not kill bacteria).

Employees should label every food item in the fridge. Keep a pen or marker and tape near the fridge to make labeling easier.

Any perishable item meant to be shared with staff should be labeled "For Staff." The date it was originally refrigerated should also be noted.

Refrigerate perishable food in shallow containers. And don't put too much food in each container.

If you spill something in the fridge, clean it.

Develop a staff policy on leftovers/lunches and post it on the fridge.

(It's recommended employees take food home daily)

Assign someone to clean the fridge once a week. In smaller offices, rotate fridge duty. Have a sign-off sheet near the fridge to ensure it's being cleaned out.

Keep a thermometer in the fridge so you know the food is really getting chilled.

Don't think you can simply avoid the fridge. Perishable items (meat, poultry, eggs, cooked pasta, fresh-peeled fruits and vegetables) should not be left at room temperature for more than two hours. (A single bacterium can grow to more than 2,000 in just 7 hours at room temperature).