Food-borne illnesses keep millions of Canadians in their bathrooms – and sometimes the hospital – every year.
Although many of them cause similar symptoms, like vomiting and diarrhea, there are many bacteria and parasites that can make you sick.
According to a recent report from the Centres for Disease Control, the top culprit in the U.S. is Campylobacter bacteria. The Public Health Agency of Canada estimates that norovirus causes the most illnesses up here.
Here is a look at some of the most common food-borne illnesses:
Norovirus
Noroviruses are a group of viruses that cause gastric symptoms like nausea, vomiting and diarrhea. Most people recover in one or two days, according to PHAC, but they estimate that it causes about 21 deaths in Canada every year.
Because it’s a virus, infected people can also spread it to others.
In Canada, one of the big food sources of norovirus is shellfish, said Lawrence Goodridge, a professor at the Canadian Research Institute for Food Safety at the University of Guelph. In 2018, 176 people got sick from norovirus-infected B.C. oysters.
Campylobacter
Campylobacter, the top cause of food-borne illness in the U.S., usually causes diarrhea, sometimes even bloody diarrhea. Symptoms might last as long as a week, according to the CDC.
“It’s a bacteria that is primarily associated with poultry,” said Goodridge. “And it tends to cause a lot of infections globally in poultry.”
According to the CDC, some Campylobacter bacteria have developed resistance to antibiotics used to treat the infection. Pet store puppies caused a U.S. outbreak of multidrug-resistant Campylobacter from 2016 to 2018 that sickened 113 people.
Salmonella
Salmonella is another common source of food-borne illness, often causing chills, fever, nausea, diarrhea, vomiting, stomach cramps and headache, according to PHAC. Symptoms usually last four to seven days.
PHAC has issued several warnings over the last year related to salmonella in frozen chicken products, such as chicken nuggets. As of March 22, 2019, there were three active investigations related to salmonella in chicken, including frozen breaded raw chicken products.
“The problem is that people think they’re cooked,” Goodridge said. “People take them home and microwave them, thinking they’re cooked, microwave them until they’re hot. But they essentially are eating raw poultry.”
Salmonella is found in the intestinal tracts of chicken, and a lot of raw chicken is contaminated with the bacteria, he said.
But that’s not the case everywhere – European chicken is much less likely to have salmonella than Canadian, he said. Statistics from the European Union found that 4.85 per cent of fresh broiler chicken meat tested positive for salmonella in 2017.
In Canada, according to an older test done by the Canadian Food Inspection Agency in 2012-13, about 21 per cent of whole chicken carcasses tested positive for salmonella, or 32 per cent of chicken parts.
According to the Canadian Food Inspection Agency, it’s hard to make comparisons between countries due to differences in testing methods and record-keeping.
“While it does appear that the prevalence on poultry meat is lower in the E.U. than in Canada, we see very similar rates of illness for Salmonella per 100,000 persons,” they wrote in a statement.
The EU rate was 20.4 cases per 100,000 population in 2016, and Canada’s was 21.03, according to data from PHAC and the EU.
Salmonella is also found in eggs, says PHAC, and in raw fruits and vegetables.
E. coli
Some strains of E. coli cause those familiar food poisoning symptoms: cramping, vomiting, diarrhea and nausea. Most symptoms end within five to 10 days, PHAC says.
The bacteria come from poop. Animal feces can carry the pathogen, and it spreads when it contacts meat, water or vegetables. Some recent outbreaks involving raw vegetables, like one in 2018 involving romaine lettuce, may have been linked to contaminated water used on the farm.
Preventing illness
Generally, you can help prevent foodborne illness by washing your hands, cooking foods thoroughly, and washing raw fruits and vegetables before eating them.
With produce that’s meant to be eaten raw, like salad, washing is a bit trickier, Goodridge said.
“You’re not washing off 100 per cent.”
Food like packaged salad mix might be more dangerous than a head of lettuce, he said.
“The rule of thumb is that the more food is handled then the higher the chances of contamination.”
With a head of lettuce, if you remove the outer leaves and wash the rest, you reduce the risk of infection, he said.