Holiday parties are always packed with lots of good foods and drinks. But if you're playing the role of hostess this year, it could also mean lots of leftovers. Before you pack up the containers, beware that there are some foods that should be thrown out and not saved.

We got this email from a viewer:

Dear Dr. Manny,
I recently hosted a holiday party at my house and have a ton of leftovers. Are there any appetizers that I might be able to save without the risk of getting sick?
Thanks,
Tonya

Contrary to what most people think, you cannot tell if a food is safe to eat just by looking at it and smelling it.

In fact, illness-causing bacteria can grow in foods within two hours if you don’t refrigerate them.

“When food is left out for long periods of time, bacteria will quickly grow and could cause a food-borne illness; some can be as serious as kidney failure,” Jacqueline Gomes, a registered dietitian and owner of CKO Kickboxing in New Jersey told FoxNews.com. “Storing leftovers within the two-hour window will help increase their lifespan.”

Gomes said although it may be tempting to save all your party leftovers in the fridge, there are some important timelines to keep in mind:

Leftovers shelf life:

Crackers: up to the sell by date.  
Deli meats: 3-5 days
Deviled eggs and mini meatballs: 4-5 days
Dips and shellfish: 2-3 days max.
Hard Cheeses: 3-4 weeks
Raw Veggies: 4 days
Soft cheeses: 1 week

Reheating leftovers properly is just as important. According to U.S. Department of Agriculture (USDA), leftovers should be reheated to 165 degrees Fahrenheit. Use a food thermometer to check the internal temperature of the food before consuming it.

Do you have a health question for Dr. Manny? Please send it to DrManny@FoxNews.com.