An E. coli outbreak from romaine lettuce has sickened at least 79 people in 15 states — here’s how to avoid getting sick

  • At least 79 people have gotten sick across the US and Canada after eating romaine lettuce contaminated with E. coli bacteria.
  • No deaths have been reported, but at least two people developed kidney failure.
  • The CDC says it’s now ok to eat romaine, as long as you can confirm it wasn’t grown in California.

Good news, salad lovers. If you can confirm that your romaine lettuce didn’t come from a California farm, then munch on.

The Centres for Disease Control and Prevention (CDC) has revised its earlier advice that all romaine – including the pre-chopped variety, whole heads, and hearts – should be avoided. CDC investigators believe they have found the source of contamination in a multistate outbreak of E. coli. The culprit lies somewhere in California’s central coast growing region.

But figuring out where your greens come from is no easy task.

Salad labelling is voluntary, though the US Food and Drug Administration (FDA) said more labels may eventually list growing region and harvest date.

“Some romaine lettuce products are now labelled with a harvest location by region,” the CDC said on its website, adding, “if you do not know where the romaine is from, do not eat it.”

At least 79 people across 15 US states and Canada developed E. coli infections in October and November, and at least 19 individuals in the US went to the hospital. The strain in question can cause bloody diarrhoea, stomach cramps, vomiting, and kidney failure. So far, two patients in the US 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 originally told everyone not to eat romaine on Thanksgiving, just to be safe. The CDC and FDA also urged all shoppers and businesses to throw out any romaine lettuce in the fridge and sanitize the areas where it was stored.

“It was critically important to have a ‘clean break’ in the romaine supply available to consumers in the U.S. in order to purge the market of potentially contaminated romaine lettuce related to the current outbreak,” the FDA said.

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 still suggests tossing it all in the trash unless you can confirm it’s not from California.

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

Because the CDC is still investigating the E. coli outbreak, the warning about California-grown romaine does not have an end-date yet.

Meanwhile, prices for other types of lettuce have soared. Iceberg and green leaf varieties were now more than double the usual price last week, as people opted for alternative salad greens,Bloomberg reported.

Caesar salad

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. That’s because there are many opportunities for bacteria to spread to these products and they’re usually eaten raw, so bacteria aren’t killed by cooking. Washing produce can reduce some contamination, but not all.

E. coli Bacteria
E. coli Flickr/NIAID

Investigators have performed genome sequencing on the E. coli strain 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. The strain is especially dangerous for people because it produces a nasty Shiga toxin. This kind of Shiga-toxin-producing E. coli, or STEC, as it’s sometimes called, spreads to humans when little bits of faeces get inside the mouth. That’s why a bit of undercooked meat, raw milk, or contaminated lettuce can make you ill.

Most often, E. coli gets on lettuce leaves after travelling from cattle farms to nearby fields. It can also get on lettuce when food handlers don’t wash their hands properly after coming into contact with E. coli-harboring faeces.

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

Kevin Loria contributed to an earlier version of this story.