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Listeria, Salmonella and E. coli are behind many food recalls in Canada. Here's what to do if you've eaten contaminated food, what symptoms to expect and how to protect yourself in the future.
Food contamination alerts seem to be happening more frequently than ever—recalls from Listeria in chocolate milk, Salmonella in tea and E. coli in pork products have all been in the headlines. But how dangerous are these contaminated foods? And what should you do if you've already eaten them? We asked Jeffrey Farber, director of the Canadian Research Institute in Food Safety and professor in the Department of Food Science at the University of Guelph, to answer our biggest questions about the fallout from eating foods containing some of the most common contaminants: Listeria, E. coli and Salmonella.
What should you do if you think you've had contaminated food?
Farber says to start by double-bagging and throwing it out, or returning it to wherever you brought it. If you're in a high-risk group (i.e., you're young, elderly, immunocompromised or pregnant) and you're experiencing symptoms, call your doctor right away. For everyone else, Farber says recovery is all about replacing lost fluids, keeping yourself nourished and tending to any aches and pains that develop when you're sick. The illness will typically go away on its own. If you are experiencing more serious symptoms (think: blood in the stool, neurological symptoms or a high fever that lasts a few days) or symptoms that persist for a prolonged time (think: diarrhea that lasts more than three to five days), go see your doctor. In most cases involving E. coli and Salmonella, your doctor won't prescribe any antibiotics, but if you've developed listeriosis from contact with Listeria, you'll likely be prescribed antibiotics.
What are the symptoms?
If you come into contact with Salmonella, you may develop salmonellosis, which mainly affects your gut, says Farber. "Symptoms include the sudden onset or diarrhea, fever, abdominal cramps, nausea and vomiting." These symptoms will usually appear within one to three days.
"For E. coli, the symptoms can vary from person to person," Farber explains. However,
some of the most common side effects are severe stomach cramps, diarrhea, vomiting and a low fever (usually less than 38.5ËšC/101ËšF). The incubation period for E. coli is one to 10 days, but most people see symptoms within three to four days. One strain of E. coli (known as E. coli O157:H7) can lead to hemolytic uremic syndrome (HUS) in about five to 10 percent of patients. The symptoms of HUS vary—some people experience seizures or strokes, while some need blood transfusions and kidney dialysis—and though it's rare, it can be fatal.
Listeriosis, which results from ingesting the Listeria bacteria, can involve vomiting, nausea, cramps, muscle aches, diarrhea, severe headaches and persistent fevers, all of which should appear one to three days after eating a contaminated food. "In the serious cases, when the infection spreads to the central nervous system, symptoms can include headache, stiff neck, confusion and loss of balance," says Farber. This more serious form can take longer—usually about 21 days—to appear, and it could be followed by serious side-effects like meningoencephalitis (an infection of the brain and its surrounding tissues), which occurs in about 20 percent of patients with severe listeriosis.
How dangerous are these contaminated foods?
Most people will just have a few unpleasant days of illness, but a small percentage of those who eat contaminated foods will experience serious and potentially life-threatening issues that go far beyond tummy troubles, so it's important to heed any warnings and recalls.
Are there any ways to protect yourself from food-borne illness?
Yes! Lots, according to Farber. To begin with, wash your hands before and after handling different foods and clean your tools and countertop to avoid any cross-contamination. Wash fruits and veggies under running water to rinse bacteria away. (Don't submerge them in water, because your sink is likely teaming with bacteria.) "Cooking food to proper temperatures is very important because the heat will kill most bacteria, including Salmonella, Listeria, and E. coli," says Farber. He suggests using a thermometer to measure the internal temperature to be sure. And after it's cooked? Refrigerate food at 4°C/39°F as soon as possible—you don't need to let it cool first. "Proper refrigeration keeps most types of bacteria from growing to numbers that can cause illness."
What foods are the worst offenders for harbouring these bacteria?
Farber says it's tough to label the worst offenders because there are so many different foods that have caused outbreaks, but he named a few. "For Listeria, foods most often involved in outbreaks have historically been soft and semi-soft cheeses and ready-to-eat meats. However, lately, fruits and vegetables have been causing illnesses," he says. When it comes to Salmonella, he says chicken, turkey, eggs, sprouts, cantaloupe, tree nuts and peanut butter have all been contaminated. "For E. coli O157, although it was historically only linked to ground beef, we now know that many other foods, such as produce and flour, can be implicated in food-borne outbreaks."
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