You can't keep anything in your stomach, your head's pounding and you're feverish. It's just the flu, right? Maybe. Maybe not. You could be one of the 7 million Americans a year who are hit by food poisoning. Over 85 percent of those cases could have been avoided if people handled food safely.

A booklet published by the U.S. Department of Agriculture will teach you how to protect yourself and your family from food poisoning."A Quick Consumer Guide to Safe Food Handling" (item 574X, free) has fold-out charts that teach you how to purchase, store and prepare food to prevent contamination and illness. For a free copy send your name and address to Consumer Information Center, Department 574X, Pueblo, CO 81009.

Food poisoning is caused by bacteria that grow in perishable foods, especially meats and dairy products. It's often mistaken for the flu because the symptoms include nausea, vomiting, diarrhea and fever.

Most signs of food poisoning occur four to 48 hours after eating the affected food. If symptoms are severe, or the victim is very young or very old, get medical help right away.

The first step in preventing food poisoning is to shop carefully. Buy only foods that you can use before their use date. Be sure the packaging is in good condition. Dented cans, torn packaging or soft rather than solid frozen food could mean bacterial contamination.

When you get your groceries home, refrigerate them immediately. To help determine how cold your refrigerator should be, use the booklet's chart listing temperatures at which you should refrigerate or freeze perishables and how long you should keep them.

When you refrigerate raw beef, for example, put it on a plate so juices that may contain bacteria won't drip on and contaminate other foods. Thaw frozen meats on a plate in the refrigerator or in the microwave and not on the counter. Bacteria can grow on the warmer outer layers of foods at room temperature while the center is still frozen solid.

As you prepare food, keep in mind that cleanli-ness is crucial. Scrub your hands, cutting boards and utensils in hot, soapy water. Clean knives and boards between cutting different foods and use a plastic rather than wooden cutting board for meats and poultry.

Bacteria such as salmonella, often found in meats and poultry, settle into the grooves of wooden boards and attack anything else that comes in contact.

"A Quick Consumer Guide to Safe Food Handling" has a chart that lists temperatures at which meat, eggs and poultry should be cooked to kill bacteria. The best advice is to heat eggs until the yolks are firm and cook meat until it's well-done.

The booklet also talks about the safety of various cooking methods. The microwave is a great cooking time-saver, but it can contribute to food poisoning. Because foods are heated unevenly, bacteria-filled cold spots can remain. Use a temperature probe, rotate or stir food during cooking for even heating.

Once food is cooked, don't leave it out of the refrigerator for more than two hours. When it comes to all foods, if they look or smell strange, don't taste them.

If you'd like more information on food handling, call USDA's Meat and Poultry Hotline, 10 a.m. to 4 p.m. Eastern Time, weekdays, at 1-800-535-4555.