Not to be too alarmist or anything, but if you’re a regular consumer of Caesar salads, you’ll want to read this. A new study by researchers at Purdue University shows that listeria (the bacteria you’ve been reading about in all kinds of recent food recalls) can live inside the tissue of romaine lettuce in every stage of the plant growth process — and survive after the conventional post-harvest sanitation process. Noooo.
Researchers from Purdue’s Department of Food Science, led by Amanda Deering, found that exposing lettuce to the bacteria could lead to infection of plant tissue in as little as 30 minutes. They also showed that the bacteria, which likely gets into the plant through small tears in the roots when romaine first begins to grow, could thrive up to 60 days or longer in its leaves.
Listeria is something you might usually associate with meats like salami and hot dogs, but this recent research joins other findings that listeriosis — the disease associated with the bacteria — can also be caused by contamination of celery, cantaloupe, sprouts and apples. When you consider that about 1,600 people get listeriosis every year, and roughly 260 die, it’s a good thing these researchers decided to examine just how at risk our beloved romaine is.
So how do you know if you’ve got listeriosis? Symptoms include fever, muscle aches, vomiting and diarrhea. And they can be sneaky, not appearing until up to two months after consumption. But it’s pregnant women — where infection can lead to miscarriage, stillbirth or premature delivery — newborns, adults over 65 and people with weakened immune systems that really need to be on high alert, especially if they experience more severe symptoms, which can ultimately lead to death. For these vulnerable populations, Deering suggests opting for produce that is either canned or cooked. Yeah, no fun at all — sorry, guys.
The silver lining is that researchers at places like Purdue’s Center for Food Safety Engineering are using this (scary) intel to inform future efforts to prevent food contamination before it’s harvested, since by that point, there’s only so much that can be done to sanitize the crops. Yep, that means even the most thorough lettuce-rinsers among us could be at risk of consuming contaminated romaine, if you’re unlucky enough to pick some up. We’re not saying you shouldn’t eat Caesar salads anymore — just be aware of who you serve it to at dinner, how often you eat it and in the unlikely event that you experience mysterious symptoms, don’t forget that this sneaky culprit could be at play.