An E. coli outbreak from romaine lettuce has sickened 50 people — here’s how to avoid getting sick

• At least 50 people have gotten sick across the US and Canada after eating romaine lettuce contaminated with E. coli bacteria.
• No deaths have been reported, but one person developed kidney failure.
• For now, the CDC recommends avoiding all romaine lettuce.

Salad eaters beware: Romaine lettuce, once again, may not be safe to eat, according to the Centers for Disease Control and Prevention.

All romaine – including the pre-chopped variety, whole heads, and hearts – has been linked to a multistate outbreak of a nasty strain of E. coli that can cause bloody diarrhea, stomach cramps, vomiting, and kidney failure.

“Consumers who have any type of romaine lettuce in their home should not eat it and should throw it away,” the CDC said Tuesday. “At this time, no common grower, supplier, distributor, or brand of romaine lettuce has been identified.”

At least 50 people across 11 US states and Canada developed E. coli infections in October, and at least 13 individuals in the US had to be rushed to the hospital. So far, one victim of the E. coli outbreak developed a type of kidney failure called hemolytic uremic syndrome, but no deaths have been reported.

Because it typically takes a few weeks for new illnesses to be reported to the CDC, the agency is telling everyone not to eat romaine this Thanksgiving out of an abundance of caution, since bad lettuce could still be out there. The CDC is urging shoppers and businesses to throw out any lettuce that was in the fridge and sanitize the areas where it was stored.

When will it be safe to buy romaine lettuce?

Since ill people reported eating several different kinds of romaine lettuce, both at home and in restaurants, the CDC is suggesting a very cautious approach for now: throwing it all away.

In some cases, it may not be clear whether a mix of “spring greens” contains romaine either, so be careful about those, too.

Because the CDC is still investigating the E. coli outbreak, they’re concerned that new cases may continue popping up – it can take 10 days for symptoms of E. coli show up. So the warning about romaine lettuce does not have an end-date yet.

A nasty strain of E. coli

Leafy greens like romaine or spinach are the most common sources of foodborne illness infections, according to an analysis by the CDC. There are many opportunities for bacteria to spread to these products and they’re usually eaten raw, which means bacteria aren’t killed by cooking. Washing produce can reduce some contamination, but it doesn’t kill bacteria.

Investigators have performed whole genome sequencing on the E. coli in question and found that this particular strain, E. coli O157:H7, is most similar to one that sickened 25 people who ate leafy greens (including romaine lettuce) last November and December. One Californian died during that outbreak. In May of last year, O157:H7 also turned up in soy-nut butter. Thirty-two people got sick, and nine developed kidney failure. Earlier this spring, another deadly O157:H7 strain sickened near 200 people and killed 5, but it was less genetically similar to this strain.

O157:H7 usually originates in the guts of cattle, but it can also be found in goats, sheep, deer, and elk as well. It can travel from cattle farms to nearby fields where lettuce is grown and contaminate the greens in the soil. It can also get on the lettuce when food-handlers don’t wash their hands properly after coming into contact with E. coli-harboring feces.

The O157:H7 strain is especially dangerous for people because it produces a nasty Shiga toxin that can make us really sick. This kind of Shiga-toxin-producing E. coli, or STEC, as it’s sometimes called, spreads to humans when little bits of feces get inside our mouth. That’s why a bit of undercooked meat, raw milk, or contaminated lettuce can make you ill.

So until the CDC issues an all-clear update, continue to avoid romaine.

Kevin Loria contributed to an earlier version of this story.