When is that party pizza past its prime? The U.S. Department of Agriculture has a food-safety tip sheet for college students.

College: A time of cold pizza, microwaved concoctions and ramen. Lots of ramen.

Whether crammed into a dorm or an apartment, part of surviving college is learning to feed yourself away from the guidance of family. Many young cooks are pulling together meals with little to no knowledge of food safety, not to mention cooking.

So the U.S. Department of Agriculture hopes to help collegiate cooks with a tip sheet on food safety, including when tailgate food is past its prime to packing tips for road-trip food to when you should leave that old pizza be.

See the entire list at http://www.fsis.usda.gov/PDF/Food_Safety_Tips_for_College_Students.pdf.

Here’s a sampling of the tips.

– Cold pizza for breakfast? Not if it’s been out on the desk for more than two hours, even if it’s meatless. Food-borne bacteria that may be present grow fastest at temperatures between 40 and 140 degrees and can double in number every 20 minutes.

– Keep perishable snacks cold during your treks around campus in an insulated lunch bag with an ice pack or double-bag items to create insulation. If there’s a fridge handy, stash food as soon as possible.

– When tailgating with friends for hours on end, store perishables like meat, potato salad and chicken in a cooler except when serving to reduce the risk of food-borne illness. Don’t leave food out of the cooler or off the grill for more than two hours, or one hour when the outside temperature is above 90 degrees.

– The most important things to remember about food safety? Wash hands and surfaces often. Separate raw meat, poultry and egg products from cooked foods to avoid cross-contamination. Use a food thermometer to ensure cooked foods have reached a high enough temperature to kill any harmful bacteria that might be present. And refrigerate leftovers promptly.