The uncomfortable reasons human waste keeps turning up in your lettuce

**David Greene** (0:04)
This is In Conversation from Apple News. I'm David Greene in for Shumita Basu. Today, what a summer of foodborne illness reveals about food safety in the US.
This summer, Americans were hit with the worst outbreak of cyclospora on record. The CDC suspects that more than 22,000 people in 15 states have been sickened by the parasitic infection, which has been linked to contaminated iceberg lettuce imported from Mexico. But it's not the only outbreak of a foodborne illness this season. In the past two months, there have been multiple salmonella outbreaks, including one tied to eggs and another to jalapenos that have sickened over 400 people. And there have been smaller outbreaks of E coli linked to frozen berries and listeria tied to soft cheese.

**Timothy Lytton** (0:56)
You need to be generally aware of the fact that whenever you eat something, there's a risk involved in that. And I think people are surprised by this in part because it's such an intimate thing.

**David Greene** (1:07)
That is Timothy Lytton. He's a law professor at Georgia State University and the author of Outbreak, Foodborne Illness and the Struggle for Food Safety.

**Timothy Lytton** (1:15)
The place where you feel most insulated from the world, your own home, where you're making your own meals and you're sitting down to family dinner, there's risk just like there is out there in the big wide world, and you can't avoid it no matter where you get your food from.

**David Greene** (1:28)
Acting FDA Commissioner Kyle Diamantis said this week that the agency was confident that lettuce related to the cyclospora outbreak had been effectively removed from the market and that Americans should feel confident in eating fresh produce. But the CDC estimates that there are roughly 48 million cases of foodborne illness in the US each year. That includes roughly 128,000 hospitalizations and 3,000 deaths annually. And this year, all those numbers feel somehow closer, more real to us. So I wanted to talk to Timothy about how our food safety system actually works, how it got to this point, and what recent outbreaks reveal about the changes needed to make us all safer.
Can we start with the most basic question in the world? What exactly is cyclospora?

**Timothy Lytton** (2:20)
Cyclospora is a parasite that only lives in the human intestines.
And so it's only passed through human fecal matter. What happens is that a person ingests food that usually is contaminated with these one cell organisms that turn into cyclospora, they're called oocytes, and that food goes into a person, and the oocyte in their intestines lodges into the wall of the intestine and produces parasites. And they start to multiply. And when those parasites multiply, they block a person's ingestion of food, which makes them very sick and causes diarrhea, nausea, vomiting. And over time, the person, when they go to the bathroom, sheds these oocytes, these sort of their one cell organisms. They're not exactly eggs because they don't hatch. And they go out into the world through human fecal matter. And if that human fecal matter comes into contact with food, another person ingests them. And so when they get re-ingested, the cycle begins again. And so that's really the only way that they spread. They don't live in animals. They're not in animal poop. They're only in human fecal matter.

**David Greene** (3:24)
It's amazing. That's been the amazing thing with the story. It goes basically from a human to human fecal matter and then somehow can get in food that gets ingested by another human. And we see this cycle continuing. That's how it spreads.

**Timothy Lytton** (3:36)
That's right. The one thing that we are pretty confident about when it comes to cyclospora is that people who get cyclospora infection are eating food that's contaminated with human fecal matter. And that occurs really primarily in the growing environment where, let's say, for example, there's contaminated water that's used to irrigate plants or to spread some sort of pesticide on them. The pesticide is mixed with water. That water that's contaminated with some sort of sewage or human fecal matter gets spread all over the crops, and off it goes into the food system. And that could be either through bad worker sanitation or poor municipal waste management. There are lots of ways in which, unfortunately, human fecal matter comes into contact with human food. It's especially bad in fresh produce because it's subjected to water, it's grown outside. There's no way to grow crops at scale with municipal tap water. So you have to take it from irrigation ditches or from wells or from canals. And those are all places that are subject to some sort of contamination through overflow from human sewage.