The recall of flour in Canada has now expanded beyond the Robin Hood brand and includes , all over concerns the flour could be contaminated with E. coli.
with a matching and dangerous strain of E.coli O121; six of them have needed to be hospitalized. The actual number of infected Canadians could be even higher, since E. coli sometimes causes only mild illness that might never be reported to hospitals.
Most of us associate E. coli with raw ground beef or unpasteurized milk. But flour? How does that get contaminated with bacteria?
Food safety expert Scott Lougheed, a PhD candidate in the School of Environmental Studies at Queen's University, says while E. coli outbreaks caused by flour are not common, they can happen.
E. coli is a bacterium that lives in the digestive tracts of humans and animals. Lougheed says it鈥檚 possible that if an infected animal or rodent walks through a wheat field and defecates there, they could leave infected feces behind. That material could then be gathered up by a wheat harvester and spread throughout the harvested grain.
鈥淟ike many bacteria, E. coli prefer warm and moist environments,鈥� says Lougheed, and flour mills can be ideal places for that bacteria to then grow.
The friction of the mills can create enough warmth to allow the bacteria to multiply, but not enough heat to kill it. And if any humidity enters the mill or the grain holding tanks, that can set up the ideal growth conditions.
E. coli also has the ability to survive in a dry environment, such as inside a flour bag on a store shelf. When that flour arrives home to our cupboards, it is still essentially the same wheat, Lougheed says.
鈥淲hen we use it, it鈥檚 in its raw form. It鈥檚 been milled and ground, but it鈥檚 raw. From the field to our counters, it hasn鈥檛 been cooked,鈥� he explained to CTVNews.ca.
Other grains such as oats are steamed at the mill before they are rolled or cut; barley or rice are usually eaten cooked. But flour remains raw wheat.
The danger from contaminated flour isn鈥檛 that it ends up in our recipes. In fact, baking the flour will kill the E. coli. The real problem is that uncooked flour tends to get everywhere in our kitchens when we work with it, Lougheed says.
We can contaminate our counters and kitchen items when they come into contact with raw dough, and the flour itself can find its way everywhere. Since most home bakers don鈥檛 think of flour as a potential bacterial source, they don鈥檛 usually sanitize kitchen surfaces after working with it, Lougheed says.
鈥淲e tend not to treat flour as a raw food; we treat it as a ready-to-eat product even though it鈥檚 not. So we don鈥檛 tend to wash our hands afterwards the way we would after handling raw chicken, for example,鈥� he said.
Because of that ability of flour to cross-contaminate surfaces, Lougheed says tracing flour-based E. coli outbreaks can be challenging. He says it鈥檚 often not enough to ask ill patients, 鈥淒id you eat raw cookie dough or pancake batter?鈥� What needs to be asked instead is, 鈥淒id you come into any contact with uncooked flour?鈥�
Neither Robin Hood nor Ardent Mills (where the flour was produced), has given any indication how this E. coli outbreak occurred, but Lougheed says preventing flour contamination in the first place is difficult, because of the challenges controlling conditions in farmers鈥� fields.
It is possible to heat-treat flour to kill off bacteria, but he says that process tends to ruin the flour's gluten.
鈥淪o your bread wouldn鈥檛 puff up and be as chewy, your cakes wouldn鈥檛 be as tender. You鈥檇 be pretty disappointed about how it performs in our kitchens,鈥� he said.
Irradiation could help, he says, but the general public doesn鈥檛 like the idea of irradiation and the equipment is also 鈥渆xtraordinarily expensive,鈥� says Lougheed, so smaller mills wouldn鈥檛 be able to afford it.
As this CFIA investigation continues, Lougheed expects the number of recalled brands and products will expand further.
鈥淚 expect we鈥檒l see more recalls as we go forward. Robin Hood is a big flour maker. They are very likely to have lots of wholesale customers and commercial customers,鈥� he said.
鈥淪o this is probably just the beginning.鈥�
