Navigating food safety can be confusing to say the least — what’s considered cross-contamination? Is the five-second rule real? Will raw cookie dough actually give me salmonella?
The Ubyssey spoke to Dr. Siyun Wang, a professor of food safety engineering in the Faculty of Land and Food Systems, about what makes food safe — or unsafe — and how we can prevent ourselves from getting sick.
How does food make us sick?
When you think about food safety, you might think of additives or genetically-modified foods. But those aren’t the most pressing concerns, according to food scientists.
“The major issues we are facing are usually associated with foods that are contaminated by food-borne pathogens,” said Wang.
Food-borne pathogens are a broad class of bacteria, parasites and viruses that can cause illness. The Government of Canada estimates one in eight Canadians are affected by a food-borne illness every year, with immunocompromised people being at higher risk.
The most common pathogens are bacteria — think E. coli or salmonella. These pathogens can spread through poor food handling practices, contaminated water during the growing stage of produce or the processing of raw meat.
Most illness and hospitalizations in Canada are caused by norovirus — commonly known as the stomach flu — which causes inflammation of the stomach or intestines. Norovirus is most commonly found in shellfish and salad ingredients.
What about mold?
Mold is a type of fungus that grows in groups of multicellular fibres called hyphae. It thrives in warm and high moisture environments and reproduces via spores. Because of this, molds are common on spoiled food — but sometimes they are used on purpose.
For some soft cheeses, such as brie or blue cheese, specific strains of molds are purposely used to break down the cheese’s fat or protein cells and develop its flavour. In these cases, Wang said they are safe to consume.
However, when mold grows unintentionally, Wang said we should be cautious before consuming foods with it, depending on the density of the food the mold is on.
“In general, if the food is porous enough for the mold to penetrate through, we should toss them. But if the molds are just presenting on the surface, then there's a chance that we can just cut that part of food off and eat them,” she said.
The US Food Safety and Inspection Service recommends cutting off at least one inch around the mold on non-porous and low moisture content foods, such as hard cheese or firm vegetables and fruit, since mold does not spread easily in these conditions.
So… What's safe?
The main way to improve food safety is to cook your food all the way through, since heat is effective at killing bacteria — but Wang said it’s not about how long you cook it for.
“It's about, especially for animal-derived food products, what kind of internal temperature that we are reaching.”
Internal temperature is the temperature reading at the centre of the thickest part of whatever is being cooked. It ranges between 63ºC for items like medium-rare steaks to 82ºC for whole poultry.
It’s also important to regularly wash your hands and surfaces, keep raw meat or seafood cold and separate raw meat, poultry, fish and seafood from other foods in your fridge.
Although counterintuitive, Wang noted the importance of not washing food items that might carry pathogens and will be cooked, such as raw chicken.
“By washing these products, you're essentially disseminating the potentially harmful bacteria.”
Most foods have a best before or expiration date, which can be a tricky concept for consumers, as it isn’t an indicator of how safe the food is to eat.
“The best before date is actually an indicator of how fresh the food is,” said Wang. “So basically, if you're eating it past the best before date, the freshness, the flavour, the nutritional value might not be the same.”
She said food past its best before date may still be safe to eat, while eating a food before its best before date may be unsafe.
In contrast, expiration dates will only be found on specific foods that have strict nutritional requirements, such as infant formula or meal replacements. Once they have passed their expiry date, the nutritional requirements may not match up and cause harm to those specific, compromised populations.
But at the end of the day, Wang said it’s important to remember that Canada’s food supply is fairly safe and researchers are working on ways to make it even safer.
“People have been making efforts in trying to get rid of these pathogens from our food supply, and that's why we need innovative solutions to figure these out.”
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