For many Americans, Labor Day marks the grand finale to the outdoor cooking season. But an increasing number of people -- about half -- say they cook outdoors year round, says the U.S. Department of Agriculture.

But whether you're cooking under the warm September sun or during a February snowfall, you need to follow food-safety guidelines to prevent food-borne illness. The USDA offers this advice:

• When you buy meat and poultry, take it directly home from the supermarket. When you get home, refrigerate it immediately. Poultry or ground meat that won't be used within one or two days should be frozen. Other meat should be frozen within four to five days.
• Meat and poultry should be completely defrosted before it's grilled so that it cooks evenly. Use the refrigerator for slow, safe thawing or thaw sealed packages of meat and poultry in cold water. You can use a microwave to defrost meat and poultry if the meat will be placed immediately on the grill.
• When you marinate meat and poultry, do it in the refrigerator, not on the kitchen counter. If you plan to use some of the marinade as a sauce, set aside a portion of the marinade before you put raw meat or poultry in it. If you plan to re-use marinade that's been used on meat or poultry, boil the marinade to destroy any harmful bacteria.
• When you're transporting food, make sure to use an insulated cooler with enough ice or ice packs to keep the food at 40 degrees Fahrenheit or cooler. Pack food directly from the refrigerator into the cooler just before you leave home.
• When using a cooler, keep it out of direct sunlight. Avoid opening the lid too often. Pack beverages in one cooler and perishable food in another cooler.
• Meat and poultry must be kept refrigerated until it's ready to cook. Only take out amounts that will immediately be placed on the grill.
• Have a good supply of clean utensils and platters. Don't use the same platter and utensils for raw and cooked meat and poultry. Harmful bacteria in raw meat and poultry can contaminate cooked food.
• If you're away from home, find out if there's a source of clean water. If not, bring water from home for food preparation and cleaning. Or pack clean cloths and wet towelettes for cleaning surfaces and hands.
• You can partially pre-cook food in a microwave, oven or stove to reduce grilling time. But be sure the food goes immediately on the preheated grill to complete cooking.
• Meat and poultry needs to be cooked to a minimum internal temperature to kill harmful bacteria. Use a food thermometer to check. Beef, veal, lamb steaks, roasts and chops should be at least 145 degrees F. Hamburgers made of ground beef and all cuts of pork should be 160 degrees F. All poultry should be 165 degrees F. Never partially grill meat or poultry and finish cooking later.
• When reheating fully cooked meats, such as hot dogs, grill to 165 degrees Fahrenheit or until steaming hot.
• Keep hot food hot -- at least 140 degrees Fahrenheit or more -- until it's served.
• Leftovers should be promptly refrigerated. Throw out any food left out longer than two hours (one hour if the temperature is above 90 degrees Fahrenheit).

The USDA also offers advice on different cooking methods:

• Smoking. This refers to cooking food indirectly in the presence of fire. It can be done in a covered grill if a pan of water is placed beneath the meat on the grill or in an outdoor cooker especially designed for smoking foods. The temperature in a smoker should be kept at 250 degrees F to 300 degrees F. Use a food thermometer to be sure the food has reached a safe internal temperature.
• Pit roasting. This method involves cooking meat in a large, level hole in the earth. A hardwood fire is built in the pit and burns (about four to six hours) until the pit is half filled with hot coals. Cooking may require 10 to 12 hours. A food thermometer must be used to check the meat. Pit roasting is affected by many variables such as outdoor temperature, the size and thickness of the meat, and the amount of heat being generated by the coals.

Some studies have suggested a link between cancer and foods cooked by high-heat methods such as grilling, frying and broiling. Based on currently available research, eating moderate amounts of grilled meats that are cooked -- without charring -- to a safe temperature does not pose a problem, according to the USDA.

You can prevent charring by removing visible fat that can cause a flare-up on the grill. Pre-cook meat in the microwave immediately before placing it on the grill. This will reduce the amount of juice that drops on the grill. Cook food in the center of the grill and move coals to the side to prevent fat and juices from dripping on them. Cut charred areas off cooked meat.