The list of recalled foods and foodborne illness outbreaks has lately been a long one: Listeria in Boar’s Head deli meats, smoked salmon from Costco and frozen waffles from Aldi, Target and Walmart. E. coli in McDonald’s Quarter Pounders. Salmonella at Downtown Baltimore’s Fogo de Chao.

And, last week, a contaminated meal that sent dozens of employees of a Jessup seafood distributor to the hospital.

Are foodborne illnesses on the rise, or are consumers just more aware? How can you avoid eating contaminated food, and what should you do if you get food poisoning? We spoke with experts for the answers.

What causes food poisoning?

Foodborne illness can be caused by a bacteria or a virus. Some of the common bacterial infections include listeria, E. coli, salmonella, campylobacter and staphylococcus aureus. The norovirus is the most common viral culprit.

Bacteria can be introduced into food “anywhere from the farm to the grocery store, to preparation to serving — whether it’s at home, at a restaurant or at a gathering,” said Jessica Queen, a physician and assistant professor for the division of infectious disease at Johns Hopkins Medicine.

Often, Queen said, E. coli outbreaks happen when fecal matter from cattle contaminates greens and other produce. In the McDonald’s outbreak, fresh onions have drawn scrutiny, leading other fast food outlets to remove yellow onions from their menus.

Some bacteria can exist in small amounts in our food and can multiply if that food is left out at room temperature for too long or stored improperly. Norovirus, meanwhile, is usually transmitted when the person preparing a meal is ill.

What are the most commonly contaminated foods, and how long does it take to get sick?

Experts say you should be especially careful when handling raw or undercooked meat, poultry or seafood. Other foods at a greater risk of contamination include unwashed, raw vegetables, deli meats, foods containing eggs and unpasteurized milk or cheese.

Queen said there’s “quite a range” of incubation periods for foodborne illness, ranging from about an hour to several days, and occasionally even weeks. Most people, however, develop symptoms within one to three days after being exposed to contaminated food. When people become ill within hours, Queen said, that’s usually an indicator that there was bacteria producing toxins within the food.

What should you do if you get food poisoning?

Food poisoning doesn’t usually require a trip to the hospital, but it can be dangerous and occasionally fatal.

The recent Boar’s Head listeria outbreak, for instance, has been linked to 10 deaths.

The Centers for Disease Control and Prevention reported one person has died so far in the McDonald’s outbreak, which as of Oct. 25 did not include the company’s restaurants in Maryland.

Illness can be more severe for some at-risk groups, Queen said, including babies and children under 5, adults 65 and older, pregnant people and anyone with a weakened immune system.

If you get sick, you should rest, stay hydrated and monitor your symptoms. If you have a high fever that lasts for more than a day, blood in your vomit or stool, severe abdominal pain, severe watery diarrhea or vomiting that’s so bad you can’t keep food or water down, that’s a sign you should see your doctor or go to the emergency room.

“For most healthy adults it’s a self-limited illness, and you’ll get better within several days,” Queen said, “but it can be serious.”

If you seek medical treatment, doctors are likely to administer intravenous fluids to keep you hydrated. They might also take tests to determine the cause of the food poisoning, and, if it’s bacterial, they might prescribe antibiotics.

For milder cases, Queen said, you can treat diarrhea symptoms with loperamide (the drug’s brand name is Imodium) and, once your stomach has settled, begin to introduce some bland foods like toast, crackers and soup back into your diet.

What can you do to prevent food poisoning?

Taking a few simple precautions can reduce your risk of foodborne illness. Queen recommends:

Washing your hands before preparing food and before eating

Sanitizing all utensils, cutting boards and counters, especially after handling raw meats

Washing fruits and vegetables

Avoiding raw, unpasteurized dairy products

Paying attention to “best by” and “sell by” dates

Cooking meat to a safe internal temperature (you can find specific guidelines on the CDC’s website)

Keeping tabs on food recalls and foodborne illness outbreaks on the CDC’s website

At large social gatherings like parties and potlucks, Queen said, it’s important to make sure hot foods are kept hot, cold foods are kept cold and nothing is left sitting out for more than two hours.

Federal, state and local health officials also monitor restaurants and food producers and distributors to make sure they are handling food safely.

“Our goal is that everybody who buys and eats food should, in fact, be safe,” said Clifford Mitchell, director of the Environmental Health Bureau at the Maryland Department of Health. “We also want to emphasize that it is important to handle food correctly. Make sure that it’s cooked to the proper temperature, make sure people wash their hands and do all the other things that we talk about in terms of food safety, because we live in a world of germs.”

So are food poisoning cases really on the rise?

The experts we spoke with couldn’t say for sure.

“It’s difficult to say that they are on the rise,” Mitchell said. “Our food supply is big and complicated, and what we are seeing now is something that happens on a regular basis, which is that there are oftentimes food outbreaks that are relatively small, but because our food supply is so large and diffuse, it is possible to see these larger outbreaks.”

He does think the public is probably better informed about the outbreaks that do happen, thanks to advances in science, like genome sequencing, that help investigators to identify and trace foodborne illness.

“We are actually getting better at identifying them and at linking the clinical outbreaks to the products,” Mitchell said.

“It’s hard to say if there are actually more outbreaks of foodborne illness or if we’re just hearing more reporting about it,” said Queen. “I think there’s more public awareness. Food poisoning is quite common.”

Have a news tip? Contact reporter Amanda Yeager at ayeager@baltsun.com, 443-790-1738 or @amandacyeager on X.