Read this before you crack open that picnic basket.

Credit: Cheyenne Ellis

Cheyenne EllisBarbecues, picnics, pool parties...summer means a lot of great food eaten al fresco. Which also means that food ends up sitting out at room temperature for a while, or attracting a few flies.

Are you more likely to get sick from warm-weather eats? Short answer: Yes. Though chances are still good that you'll make it through the season healthy, the Centers for Disease Control and Prevention—along with other experts on foodborne illness—warn us that it's smart to take some special precautions in summer, particularly if you're pregnant or feeding kids, the elderly, or someone with a chronic illness like diabetes.

The good news: The rules to follow are not as fussy as we've sometimes been told in the past. Here, what you need to know in order to eat (almost) everything—and not get sick.

The #1 easy rule
Many food-poisoning cases year-round are caused by bacteria such as salmonella, E. coli, campylobacter, and listeria. But here's the thing about summer: All of those bacteria grow faster at warm temperatures. Combine that with lots of meals outside, sans refrigeration and running water, and you get an increase in the number of illnesses.

So the basic protocol to follow is this: "Hot foods should be kept hot and cold foods should be kept cold to prevent rapid bacterial growth," says Donald Zink, PhD, senior science adviser at the U.S. Food and Drug Administration's Center for Food Safety and Applied Nutrition.

Experts call the window between 40°F and 140°F "the danger zone," because it's between those temps that bacteria proliferate—and lots of multiplying bacteria means an increased risk of your getting sick. You can keep perishable food from drifting into the danger zone by refrigerating it or keeping it on ice (at 40°F or below) or heating it (to 140°F or above).

This is especially important when it's hot outside: "Bacteria grows rapidly at room temperature, but it grows even faster when the weather is between 90°F and 110°F," says Elisabeth Hagen, MD, U.S. Department of Agriculture (USDA) undersecretary for food safety. That's why the USDA recommends that you never leave food un-chilled for more than two hours (one hour if you're in 90° heat or hotter).

At the supermarket
Even in the swelter of summer, you can likely count on your grocery store purchases to be safe—commercial food-handling and packaging is highly regulated to keep the risk of foodborne illness low. Still, you can further protect yourself with these tips:

  • Inspect foods before you toss them into your cart. Avoid meat in leaky packaging (which can cross-contaminate other food with bacteria), check to see if chilled food is actually cold, and be sure that items from the freezer section feel frozen solid.
  • Pre-sliced fruits and veggies should be sold in a refrigerated case; if they're not, don't buy them.
  • Put raw meat and seafood on the bottom shelf of your grocery cart so that they don't risk dripping onto your other purchases. As an additional precaution, wrap them in their own plastic bag to avoid any possibility of bacteria getting onto your produce.
  • Keep cold items like eggs, meat, and frozen foods chilled by adding them to your cart last before you check out, putting them in the backseat of your car instead of your trunk on a hot day, and even bringing a cooler along if you'll be driving for more than half an hour. This will minimize the chances of any bacterial growth.

Next Page: At home [ pagebreak ] At home
You're already smart about food handling in the kitchen, but hot weather does up the ante:

  • Put hot food in the fridge immediately (rather than letting it cool first).
  • Marinate meat in the refrigerator. And don't baste with marinade that held raw meat—unless you bring it to a boil for at least five minutes first.
  • Don't wash raw meat. "That can actually increase your chance of food poisoning by splashing juices and any bacteria they might contain onto your sink and counters," Dr. Hagen says. What should you wash? Fruits and veggies, of course. Putting them under cold running tap water—and scrubbing hard-surfaced produce like apples and potatoes—can remove dirt and reduce bacteria. Cut off small bruises, since that's where bacteria like to congregate.
  • There are three ways to thaw frozen raw meat. (Hint: None of them involve leaving it on your kitchen counter.) You can defrost it in the fridge (put it on a plate to catch leaking juices), in cold water (in a watertight bag, changing the water every 30 minutes), or in the microwave. In the latter two cases, cook immediately after thawing.

At a picnic
Whether you're hosting or attending an outdoor eating fete, bacteria is the last thing you want to worry about. Here, a few basics for safe eating:

  • To keep cold food cold, designate separate ice chests for food and drinks so the food container isn't opened frequently. Stow the food cooler out of the sun, insulated with a blanket, and replenish ice so your provisions stay at 40°F (and food feels like it just came out of the fridge).
  • Always have two plates with you at the grill: one for holding the raw meat, and the other for taking it away once it's cooked. "If you use only one plate, you're putting your food right back in the same bacteria you just cooked out of it," Dr. Hagen says.
  • You may think you know what cooked-through meat looks like, but a food thermometer is really the only way to tell if you've done a thorough job. Cook to these temps, measuring in the thickest part:
    • 165° Poultry (whole and ground)
    • 160° Ground beef, lamb, veal, or pork; sausages
    • 145° Beef steaks, lamb, pork chops, and seafood (and let them rest at that heat for three minutes before serving to get rid of bacteria)
  • If you like your burger less well-done, there may be a way to play it safer (though there's always some risk—especially for kids and older people): "Ask a butcher to grind meat from an inside cut, like the eye of the loin," says Peter Snyder, PhD, president of food-safety consulting group the Hospitality Institute of Technology and Management. "Packaged ground beef tends to be trim meat from the outside of the cow, which can get contaminated during the butchering process." A single patty from the store can also contain meat from hundreds of animals—which ups the risk that it's contaminated. If you get your ground beef from a single cow instead, the chances of it containing dangerous bacteria are usually lower.
  • Keep those hands clean. Germs on your paws can contaminate food and spread bacteria from raw food to cooked food. For outdoor events, an alcohol-based sanitizer with 60 percent alcohol is best, Dr. Hagen advises.