The U.S. Food and Drug Administration (FDA) last month issued a voluntary recall on red, yellow, white, and sweet yellow onions, over salmonella contamination concerns. Now the FDA, along with the Centers for Disease Control and Prevention (CDC) and state and local partners, is investigating a multistate outbreak of salmonella infections potentially linked to peaches. The CDC is reporting at least 78 cases in 12 states; and recalls have been issued in Canada, Singapore, and New Zealand. Here are 10 things you need to know about salmonella, from transmission and prevention to surprising complications and even some fun facts.
1. Certain Foods Are More Common Culprits for Salmonella Infection
While salmonella outbreaks have involved everything from precut melon to frozen shredded coconut pistachios, the bacteria usually infects chicken, beef, poultry, milk, and egg products, says Rita M. Knotts, MD, a gastroenterologist at NYU Langone in New York City. Salmonella outbreaks in poultry account for approximately 19 percent of salmonellosis cases, eggs for 14.8 percent, and beef for 7 percent, according to the International Association for Food Protection. “Salmonella is transmitted through fecal-oral routes, so there’s got to have been some contact that was made with these products, possibly through the water that washed it,” Dr. Knotts says. “It’s probably unwashed hands of the food workers, or how they washed it that has led to cross contamination.” In order to reduce your risk of infection, be sure to wash your hands thoroughly before and after handling food. Washing fresh produce with water helps remove harmful bacteria and germs, but it doesn’t completely get rid of them. The CDC recommends buying prepackaged leafy greens or veggies that are labeled “triple-washed” or “ready to eat.” However, you should never wash poultry or meat before cooking, as raw juices can splash and contaminate other foods, utensils, and surfaces. Washing your hands, keeping your kitchen clean, and avoiding reusing cutting boards can help protect you and your family from food poisoning. Thoroughly cooking chicken and meat is key to killing the bacteria. According to federal food safety guidelines, chicken should reach a minimum internal temperature of 165 degrees F, and beef should reach 145 degrees F.
2. Salmonella Can Spread From Person to Person — and Even From Contact With Animals
“Salmonella can be transmitted from person to person via fecal oral transmission,” Knotts says. “Many years ago, there was someone called Typhoid Mary, and she basically caused the salmonella outbreak [in New York in the early 1900s] because she didn’t wash her hands and went from house to house, cooking in people’s houses.” It goes without saying that you should also always wash your hands after using the toilet or changing a dirty diaper. Generally speaking, Knotts says that person-to-person transmission is rare. “It’s not an airborne kind of transmission, like COVID-19. You actually have to ingest the salmonella, and that’s usually from the feces of an infected animal, or if you’ve consumed something that was contaminated with salmonella,” she says. However, you can also be exposed to salmonella through direct contact with certain infected animals. This July, for example, the CDC and public health officials in 48 states reported that they were investigating 15 multistate outbreaks of salmonella infections linked to contact with poultry in backyard flocks, such as chicks and ducklings. “Backyard poultry can carry Salmonella bacteria even if they look healthy and clean and show no signs of illness,” according to the CDC. That’s why you should “always wash your hands with soap and water right after touching backyard poultry, their eggs, or anything in the area where they live and roam.”
3. There’s More Than One Strain of the Bacteria
When we say “salmonella,” we’re actually referring to many strains of bacteria. According to the CDC, more than 2,500 group or serotypes of salmonella have been identified — 100 of which account for most human infections. The two most common strain types in the U.S. that cause illness are typhoidal salmonella, also known as Salmonella Typhi, and nontyphoidal salmonella. Typhoid fever is a life-threatening illness caused by Salmonella enterica serotype Typhi and Salmonella enterica serotype Paratyphi. Most people become infected with typhoid fever after traveling abroad to certain areas where the disease is common. In addition to having a fever, other symptoms of typhoid and paratyphoid fever include stomach pain, diarrhea, constipation, headache, loss of appetite, and weakness.
4. Pets Can Carry Salmonella Without the Bacteria Posing a Threat to Them
Pets usually become infected with salmonella from eating pet food or drinking water contaminated with the bacteria. Salmonellosis isn’t common in dogs and cats, and pets that have it usually don’t show any symptoms. But they can be carriers of the bacteria and transmit the illness to you, the FDA reports. Dogs, for example, can spread the bacteria through their stools and saliva because the bacteria lives in their intestinal tract. Cats can spread it by jumping on kitchen countertops or dining tables. Health experts strongly encourage people to thoroughly wash their hands after picking up pets’ feces and cleaning their crates and litter boxes. It’s hard to say no to your furry friend, but you should try to keep pets away from areas where you normally prepare or eat food. Dogs can also spread the bacteria by giving people kisses, so to help you avoid infection, wash up if they lick you, and keep surfaces in your home clean. Other animals that are known to spread salmonella are turtles and lizards, chicken, ducks and geese, mice and rats, and farm animals, like goats, cows, and pigs.
5. Salmonella Infections Can Lead to Arthritis or IBS
People infected with salmonella may be at risk for a form of arthritis. According to the American College of Rheumatology, reactive arthritis is a painful inflammatory joint disease that occurs in reaction to an infection by certain bacteria in the genitals (such as chlamydia) or the bowel (such as salmonella). “You can get reactive arthritis immediately if you become infected with the bacteria. It’s the antigen that’s in the salmonella that’s impacting your joints,” Knotts says. “But I wouldn’t consider it to be a long-term complication. Usually, once the infection clears up, the arthritis clears up.” Knotts says one of the more serious, long-term salmonella-related complications to be concerned about is post-infectious irritable bowel syndrome (IBS), which can last for days, weeks, and even months. According to a study in Clinical Infectious Diseases, anywhere from 4 to 32 percent of patients with post-infectious IBS had recovered from an illness due to salmonella, among other foodborne bacteria.
6. Garlic and Cinnamon May Help Kill the Bacteria
Most salmonella-related gastroenteritis cases resolve in a week without any treatment. Patients should drink plenty of fluids to help replenish fluids lost from diarrhea and vomiting. In some severe cases, or if a person is at greater risk for complications, antibiotics may be prescribed to treat the infection. There is some evidence that common ingredients in your kitchen pantry may also help. Small studies have shown that the antimicrobial properties in cinnamon bark essential oil may combat pathogenic bacterial strains, like Salmonella Typhi and Paratyphi, according to a September 2015 review in Nutrients. Separately, an early study in BMC Complementary Medicine and Therapies, which compared the antibacterial activities in a variety of spices such as cumin, cinnamon, and clove, found that cinnamon provided the best antimicrobial defense. Research suggests that garlic’s antibacterial properties could help treating salmonellosis. A study in the Journal of Food Science found that a garlic-based marinade may reduce the viability of salmonella bacteria in food. Remember that the evidence is limited, so talk to your doctor about the potential risks versus benefits of taking essential oil orally or supplements to help treat your infection.
7. Salmonella Was Discovered by a Veterinarian Named Salmon
In 1876, Daniel Elmer Salmon, DVM, was awarded the first doctor of veterinary medicine degree in the United States, according to the USDA. After graduating from Cornell University, Dr. Salmon began investigation infectious diseases among cattle and farm animals including Texas cattle fever, hog cholera, fowl cholera, and foot-and-mouth disease. Because of Salmon’s groundbreaking work, the discovery of the pathogenic bacteria salmonella was named after him by Theobald Smith, another animal scientist who first identified the bacteria while studying hog cholera.
8. Age, Medication, and Certain Conditions Can Raise Your Risk of Salmonella Infection.
People with weakened immune systems from diabetes, heart disease, cancer, kidney disease, and HIV or AIDS are at greater risk of food poisoning infection, the CDC reports. Adults age 65 and older, as well as pregnant women and children younger than 5 years old are also at higher risk of salmonellosis. In fact, children younger than 5 are 3 times more likely to be hospitalized if they contract the salmonella infection. People who take certain medicines, like stomach acid reducers, are also at increased risk of infection.
9. Keeping Eggs Refrigerated Reduces the Chance of Infection
Storing eggs on the kitchen countertop is common practice for many Europeans, but Americans like to keep their eggs chilled — and there’s a good reason for that. Keeping eggs refrigerated at 40 degrees F or colder helps prevent the growth of harmful bacteria, including salmonella. This goes for dishes that are made with eggs, too, so don’t let them hang out at room temperature for more than two hours. Make sure to throw away any cracked or damaged eggs from your dozen, and dispose of the shells properly.
10. Salmonella Is More Common in the Summer
Salmonella illness is more common during the warmer months when temperatures rise and bacteria is more likely to grow. To reduce your risk, keep perishable food, including dairy, eggs, meats, and fresh produce, refrigerated or frozen. Don’t forget to also wrap leftovers in a container in the fridge within two hours of preparing it — one hour if it’s 90 degrees F or hotter outside. Freezing food may stop bacteria from reproducing, but it won’t kill salmonella. So you still need to be careful about how you handle, prepare, and cook any foods.
