Have you recently heard about something called “norovirus” in the news? You probably have, although it’s sometimes referred to as “food poisoning” or the “stomach flu.” Norovirus is very common and very contagious. In fact, a recent CDC study said it’s a leading cause of foodborne deaths, hospitalizations, and illnesses.
What is norovirus?
Norovirus is the leading cause of disease from contaminated foods in the United States; it is responsible for more illnesses than all other viruses, bacteria, and parasites combined. Of all foodborne disease outbreaks with a known cause in the United States, over half are caused by noroviruses.
Norovirus illness often begins suddenly. If infected, you may feel very sick, with stomach cramping, vomiting, or diarrhea. Infections are usually not serious. Most people recover within 1 or 2 days with no long-term health effects. But, more severe illness is possible, particularly in young children, older adults, and people with other health conditions. For these people, norovirus illness can lead to hospitalization and even death.
How do you get norovirus?
You can get norovirus by
- Eating food or drinking liquids that are contaminated with norovirus.
- Touching surfaces or objects contaminated with norovirus and then putting your hand or fingers in your mouth.
- Having direct contact with another person who is infected with norovirus. (for example, when you care for someone with norovirus or share foods or eating utensils with someone who is infected.)
Leafy greens (such as lettuce) and raw shellfish (such as oysters) are just two examples of foods most commonly involved in foodborne norovirus outbreaks. However, any food item that is served raw or handled after being cooked can become contaminated with noroviruses.
Norovirus can spread rapidly from person to person in crowded, closed places like long-term care facilities, daycare centers, schools, hotels, and cruise ships. Noroviruses also can be a major cause of gastroenteritis in restaurants and at catered events if contaminated food is served.
Stop the spread of norovirus
You can stop the spread of norovirus by washing your hands carefully with soap and water, especially after using the toilet and changing diapers and always before eating or preparing food. According to the latest findings from the CDC, “appropriate hand hygiene is likely the single most important method to prevent norovirus infection.”
Other food safety tips to prevent norovirus infections include
- Carefully wash fruits and vegetables.
- Cook oysters and other shellfish thoroughly before eating them.
- Do not prepare food if you’re infected. People who are infected with norovirus should not prepare food for others until 3 days after they recover from their illness.
For more tips, see Prevent the Spread of Norovirus.
Those of us on the USDA’s Meat and Poultry Hotline can always tell when St. Patrick’s Day approaches. Starting in early March, we begin to receive lots of questions about corned beef: How do you prepare it? How can you tell when it’s safely cooked? How long can you store it?
While a traditional dinner of corned beef and cabbage may bring you the “luck of the Irish,” you can’t rely on good luck to ensure that your meal is food safe. Instead, follow these tips to make sure that you and your guests don’t turn green (with food poisoning!).
Package Dating and Storage Times
If you buy uncooked corned beef in a pouch with pickling juices which has a "sell-by" date or no date, you may store it for 5 to 7 days in the refrigerator, unopened. If you buy products with a "use-by" date, you may store it unopened in the refrigerator until that date.
An uncooked corned beef brisket may be frozen for 1 month for best quality if you drain and re-wrap it. We recommended draining the brine because salt encourages rancidity and texture changes. The flavor and texture will diminish with prolonged freezing, but the product is still safe.
Corned beef is made from one of several less tender cuts of beef like the brisket, rump or round. Therefore, it requires long, moist cooking. It can be cooked on top of the stove or in the oven, microwave, or slow cooker. The USDA does not recommend one particular cooking method as best, but we do provide cooking directions in our fact sheet, Corned Beef and Food Safety. Whatever method you use, make sure that the corned beef reaches a safe minimum internal temperature of 160 °F or above.
It’s safe to cook corned beef ahead of time. After cooking, cut it into several pieces for faster cooling—or slice it, if you like. Place the beef in, shallow containers and cool it in the refrigerator quickly.
Leftover corned beef should be sliced and refrigerated promptly—within 2 hours of cooking or reheating. Use cooked-ahead or leftover corned beef within 3 to 4 days or freeze 2 to 3 months.
If you have any other questions, feel free to contact us at the Hotline (1-888-674-6854 toll-free) or online at AskKaren.gov (English and Spanish).
Being a busy mom I rely heavily on two things: leftovers and the microwave. How else would I heat up a quick lunch at work as I rush to get back to a conference call? How would I re-heat the dinner my husband missed due to our mismatched schedules?
Still, despite feeling crunched for time, I do take care to treat my food in a way that protects my family from foodborne illness. There’s much more to the safe handling of leftovers than most people realize, and following a few simple tips can save you—and your loved ones—from illness.
Put leftovers in shallow containers to cool quickly
The center of that big pot of chili you stick in the fridge isn’t going to cool down within 2 hours, and that warm spot in the middle can allow bacteria to grow. The smaller the portion size, the faster it will cool in the refrigerator. And when you go to heat it up in the microwave, it will heat much more quickly and evenly too. [USDA recommends packing leftovers so that they are less than 2 inches deep.]
Refrigerate within 2 hours
Bacteria grow rapidly at warm temperatures, and after just a few hours can reach levels that can cause illness. Refrigeration slows the growth of bacteria. The recommended temperature for your fridge is 40 °F or below (use an appliance thermometer to see how cold it is).
Foods should be refrigerated within 2 hours of preparation. Even though it may seem energy efficient to let foods cool down on the counter before sticking them in the fridge, there can be a risk if they are left out too long.
It’s important to remember that the clock starts ticking the moment your food is done cooking—so when dining out, consider the time the food is at the restaurant and the time you travel home. For more details, see Safe Handling of Take-Out Foods.
The microwave is just another way to heat food. The microwaves bounce around and literally “excite” the food. However, the microwaves may not hit every part of the food evenly. In foods with multiple ingredients (like a casserole) some ingredients may get more “heated” than others.
It’s really important that all parts of reheated food reach 165 °F before they are eaten. There are a few ways to ensure this happens:
- Stir the food in the middle of heating;
- Let the food sit for a few minutes after it finishes in the microwave to ensure the food cooks evenly. During this “standing time,” the cold parts of the food will absorb some heat from the hotter portions. Many microwave meals recommend this, so pay attention to microwave instructions.
- After the “standing time,” check the food with a food thermometer.
For more info on reheating in a microwave, see the video How to Properly Cook Foods in the Microwave.