IRA FLATOW, host:
This is TALK OF THE NATION: SCIENCE FRIDAY. I'm Ira Flatow.
As far as we know, nearly 150 people have gotten sick, at least one person has died after eating food tainted with a deadly strain of bacteria, E. coli 0157.
Public health officials suspected that the source of the infection was fresh spinach, mostly, most likely from fields in California. But it wasn't until a few days ago that they actually came up with a smoking spinach - the smoking gun, so to speak - an actual bag of spinach that had bacteria on the leaves.
Short of finding spinach with a bug on it, how do public health officials track down what might be causing an outbreak and how do they spread the word that a certain culprit might be causing a problem? And where could such a deadly strain originate?
Joining me now is one of the food detectives who helped pieced together this recent outbreak. William Keene is senior epidemiologist in the Oregon Public Health Division, Acute and Communicable Disease Program. He joins us by phone from Portland. Thanks for talking with us today, Dr. Keene.
Dr. WILLIAM KEENE (Oregon Public Health Division, Acute and Communicable Disease Program): My pleasure.
FLATOW: Talk us through this a little bit. Tell us about the first days of the outbreak. When did you first begin to suspect that it was spinach?
Dr. KEENE: Well, here in Oregon we began - we get reports of E. coli 0157 infections throughout the year, particularly in the summer months. We average over 100 cases reported in the year, so these cases do drift in almost everyday in the summer months.
It was Friday afternoon on September 8th when we got a report from our lab that we had three cases that appeared to be a match by this molecular subtyping, and that was the first inkling we had that there might be a cluster of cases.
FLATOW: So you have people that are sick on this thing. You think it's the same bug causing the illness, but you're not sure.
Dr. KEENE: Right. The system works because when people go to a doctor and they get a laboratory test for this bug and for other bugs like Salmonella or Shigella, if those tests come back positive, the results are sent to the public health system. In our state, they go to local health departments.
There's some initial follow up by local health department nurses - an interview with the patient or their parents - and they try and get information about possible exposures. But generally we're thinking about these as sporadic cases that are not linked to each other unless there's a cluster in one area.
So when the isolates come to our public health lab - and I should note that that's also a requirement in our state, that labs will forward the actual bacterial isolates to the labs for subtyping - they do this additional testing. And sometimes that identifies possible clusters that would not be apparent just from the initial interviews.
FLATOW: We're talking with William Keene. Our number, 1-800-989-8255.
Okay, so then you got to do the legwork, right? You have to go back and ask these people what did you eat?
Dr. KEENE: Right. We don't routinely ask people about spinach and lots of other possible exposures. The initial interviews that are done here in Oregon cover a number of likely exposures - contact with animals, consumption of raw milk, consumption of hamburger, swimming - but it's not an exhaustive list by any means. Sometimes, though, that's enough to identify outbreaks due to restaurant exposures or common events or swimming. In this case it didn't.
So on that Friday night, we had three cases that might be a cluster, and well, our first step is to pull out the interviews that have already been done and go through them and see if anything jumps out at us. In this case it didn't.
So we continued - over the weekend, we talked with Washington State because one of the cases that we had from our lab happened to be a Washington resident, and then it was not really until the next week, till Monday, that we begin to try and get more information from these people. Some of them were hard to reach. And Tuesday, we received a notice from our public health lab that we had two additional cases that seemed to match this pattern.
FLATOW: And how did you narrow it down to spinach?
Dr. KEENE: Well, our general procedure here is something we've been working on for years, and it's fairly cut and dry. When we think we have a cluster - and I should note that not all of these clusters turn out to be real, so we get notices of two or three that match with some regularity, and they often don't turn into much. But when we - and if the initial interviews are unsuccessful, we go to our plan B, which is something we call our shotgun questionnaire, unfortunately perhaps.
But it's a long list of hundreds of food items, and we'll - again, these people have already been interviewed, but we'll call them back and say we really need your help. Can we go through this 30 to 45 minute interview, basically asking about every food that we can think of. And then we try and see what do these people have in common. They must have eaten something in common.
FLATOW: And so what made you think it was spinach? They all said spinach? No one said sprouts?
Dr. KEENE: That's right. In this particular series of interviews, done by (unintelligible) office, the bagged spinach is what came up. And so by Wednesday morning, we had four out of five of the people who had been interviewed admitting they had eaten bagged spinach.
FLATOW: And so now you had to go look for the spinach.
Dr. KEENE: Well, again, some exposures are common. People eat eggs. They eat ground beef. It doesn't necessarily mean they, that that's the source of any given infection, so we have to compare this with some other group. Is four out of five higher than usual, or is that just background? In this case, we're part of a group with a number of other states and the CDC that's been surveying the population for years and actually, believe it not, collecting data on certain kinds of food exposure, including spinach.
So we knew that the background level of spinach consumption was not that high. It was more in the 15 to 20 percent range. So actually the four out of five we could tell right away was very unusual.
FLATOW: So, but you still didn't have any, you still didn't have that smoking spinach, the source of the spinach.
Dr. KEENE: Well, as epidemiologists, we think that these kind of interview data combined with our comparison data are actually quite strong, and the smoking spinach, which actually it was only an ounce that I think yesterday or the day before yesterday, a positive culture is something that's actually very rarely available and something that we almost never would wait for.
Typically the food that we're interested in has long been consumed, so these epidemiologic data are to us the smoking gun.
FLATOW: But then again you still want to go out and look for it if you can.
Dr. KEENE: Absolutely. In this case, with four out of five we were not 100 percent sure, but it was a matter of great concern. So when we shared this concern with colleagues at the CDC in Atlanta, we learned that there were a similar cluster under investigation in Wisconsin. Some cases had been reported already in Utah and New Mexico that appeared to match.
And within about 15 or 20 minutes of e-mail and phone calls, we quickly established that we were really all working on the same outbreak, and in fact that spinach exposure was common to the vast majority of these cases.
FLATOW: And the vast majority, the commonality was age or gender?
Dr. KEENE: Most of the cases in this outbreak tend to be female, about three to one, and the majority are adults. That's a pattern that we see in a number of kinds of outbreaks that are due to sprouts, which you mentioned, have been a recurrent source of illness. Lettuce, salad mixings in general often have that pattern.
FLATOW: I want to also bring in someone else to talk with us. Caroline Smith de Waal is a food safety director at the Center for Science in the Public Interest in Washington. She joins us by phone. Welcome back to SCIENCE FRIDAY, Dr. de Waal.
Dr. CAROLINE SMITH DE WAAL (Center for Science in the Public Interest): How are you doing?
FLATOW: Very well, Caroline. Let me ask you is it true that the FDA does not have the authority to tell stores to stop selling spinach?
Dr. DE WAAL: That's right. FDA actually doesn't have mandatory recall authority at all. But it's really a historical accident because FDA's law is based on - it was passed - the initial law was passed in 1906, so we really are lacking modern food safety management tools in many of our food laws, including FDA's.
FLATOW: And so if it were bad meat, the Department of Agriculture could recall it, but it's bad spinach, they can't do that.
Dr. DE WAAL: Actually it's all done, both meat and produce, it's all done using what are called voluntary recalls. And really the tool here for the agency is they issue a press release like they have here, and they tell the public to avoid certain foods. That triggers - that should trigger the stores removing it from the market, but none of it is mandatory.
FLATOW: Caroline, how do you rate the FDA's handling of this?
Dr. DE WAAL: Well, I think they have done very well in getting the information out to the public. They - and I have a lot of history looking at outbreaks managed by both FDA and USDA, and one thing that strikes me here is that they issued the national warning in advance of knowing the farm that the products actually came from. In the past they've delayed it, and in some cases we think that's led to increased illnesses and maybe even more outbreaks.
But where FDA really has fallen down, it's not really the agency's fault either, but they don't have the tools they need to really manage these food safety hazards on the farm.
FLATOW: They don't.
Dr. DE WAAL: No. You know, if this spinach was making other spinach sick, maybe it carried a virus that contaminated other spinach plants, we have a government agency that can go in, they can do a mandatory recall of the product, they can quarantine an area if they need to, they can do inspections. That's called the Animal and Plant Health Inspection Service, and they have on farm authority to control animal and plant diseases.
But when it comes down to problems that impact humans, we don't have the same level of control. We're dealing with hundred-year-old statutes, and FDA's budget has been cut so dramatically that it's going to be very hard to manage and see improvements in this area until FDA has the tools and the resources it needs to do the job.
FLATOW: Do you think something, an outbreak like this, might spur that kind of action?
Dr. DE WAAL: I am hoping, and we've been in touch with a number of members of Congress, that this will spur investigation and it may spur Congress to take action. But the immediate need is for FDA to just stop hemorrhaging the staff that's been so critical to managing food safety issues in the past. They've lost about 60 staff in the last year just from their policy department, and they've lost about 200 inspection staff over the last couple of years.
Congress cannot expect FDA to manage these kinds of problems unless we see that they're given modern tools and they're given the staff that they need to do it.
FLATOW: Well, we're going to take a short break. When we come back, we'll talk lots more about tracing the contaminated spinach. Our number is 1-800-989-8255, 1-800-989-TALK. Talking with Caroline Smith de Waal who is food safety director at the Center for Science in Public Interest in Washington, DC, and also with William Keene, senior epidemiologist in the Oregon Pubic Health Division, Acute and Communicable Disease Program.
We'll take your calls. Lots of people want to talk about tracking down the spinach, what we can do about it. How did the E. coli get into this spinach to begin with? All interesting questions. We'll have some answers when we get back. Don't go away.
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You're listening to TALK OF THE NATION: SCIENCE FRIDAY. I am Ira Flatow.
We're talking about the E. coli outbreak in the spinach with Caroline Smith de Waal and Bill Keene. Our number, 1-800-989-8255. Let's go to Karen in Culver, Oregon. Hi, Karen.
KAREN (Caller): Oh, hi. Thanks for taking my call. I had the question, because we've heard all this, you know, ad infinitum now about, you know, what's going on, but we haven't heard how did it actually get into the spinach?
FLATOW: That's a really good question. Let me ask Dr. Bill Keene. Do you know?
Dr. KEENE: Well, the short answer is we don't know. The longer answer is there are a lot of ways it could have gotten into spinach, just like it can get into lettuce and other vegetable crops. But we don't have specific evidence yet at this time and we may never have it.
Potential sources, though, would include wild animals running through the field, irrigation water that may be contaminated with runoff from agricultural land, flooding, farm workers in the field, problems in the processing plant. There are lots of potential routes of contamination of fresh produce.
FLATOW: Now the E. coli is ubiquitous. It's everywhere, is it not? But it's this strain that's the dangerous strain.
Dr. KEENE: Well, yes, we all carry different kinds of E. coli and most of them are harmless. E. coli turns up in well water and shouldn't be there, but it's more of a marker of fecal contamination rather than a problem per se. But this O157:H7 and similar what are called Shiga-toxigenic E. coli are fortunately relatively uncommon in people, but when they do hit, they can cause quite serious and even deadly disease.
KAREN: Where did these basic E. coli - which variety of mammal did they basically come from?
Dr. KEENE: The most commonly identified reservoir host for this are ruminant animals, so those include cattle, sheep, goats, deer, elk. Most people have more common with products from cattle in the form of beef or - so that's probably one of the more common sources for people. But the other ones have all been linked to human illness.
FLATOW: How would it get to spinach from the beef?
Dr. KEENE: Well, again, we're not talking about beef. We're talking about something that's in the environment, because if there aren't cattle upstream or deer running through the spinach field, there are water sources and there are humans that are exposed to some of those directly or indirectly. And they're all, again, potential sources and you can figure out ways that they get into the water or get into the soil and therefore get onto crops.
FLATOW: Caroline, any comment?
Dr. DE WAAL: Well, we've seen a couple of outbreaks which I think are instructive. One was an outbreak in Walkerton, Ontario, where manure actually got into well water that then served the city, the town of Walkerton, so actually tap water was making people sick.
And that's one source. There may be farm communities nearby with a cattle population. They have to watch the manure entrance points into the water supply. Also flooding is certainly a possibility where from adjacent agricultural lands, if they have flooding over into these fields that could overwhelm the washing and safety controls that are used further up.
So there are a lot of sources, but at the beginning of an outbreak like this, there's an animal reservoir which is contaminating the environment, which can be fine if it's kept in just the small area. But if it spreads into the water supply, they cause major, major outbreaks.
FLATOW: There was a very interesting 1998 study in the journal Science that was conducted by the U.S. Department of Agriculture and Cornell University, saying that they could eliminate this bad E. coli strain in cattle manure just by feeding the cattle hay instead of grain for just five days before they were slaughtered. Might that be a, you know, a long-term solution if you're wondering where this is coming from?
Dr. DE WAAL: That study has - I've talked to many people in the industry who say that's not a simple solution, unfortunately. It did look like a silver bullet for a little while, but apparently it hasn't held up. So - but we do need ideas like that. We need ways of raising cattle that make them less likely to harbor harmful bacteria.
I mean there - some people believe, and I think there's some evidence to support this, that grass-fed beef are more likely to have - or less likely to have these harmful strains of bacteria. It doesn't survive as well in grass-fed animals as it does in those fed corn and the richer diets that they're used to.
FLATOW: What about if - what about locally produced spinach? If you can go to your local spinach produce farmer, and he's growing it right there on the field that you can watch, would it be safe to still eat the spinach this week?
Dr. KEENE: This outbreak is caused by a specific problem at a specific field or a specific packaging house, so spinach from another source is not really part of that problem, not part of this outbreak. Spinach, in general, just like all kinds of similar crops - lettuce, arugula - these are all exposed to the same potential risk because they're grown in the open, and if you're eating them raw, there isn't a kill step.
Some of the industrialized products have a different wrinkle because when in the processing they're often mixed with product from a larger area, and a problem that may be on a few plants can get spread to a larger number of people and a larger number of packages than stuff from your backyard or from a farmer's market.
But generically, they all have some risk. The risk is minimal in general, but people are looking into ways to reduce the risk.
FLATOW: And how - and, Caroline, how can we reduce the risk? How do we keep this from happening over and over again?
Dr. DE WAAL: Well, one of the things that's really coming clear in this outbreak is that this - the consumers need to treat these bagged lettuce products and a lot of our produce the same way we treat meat and poultry in the sense that we've got to keep it in the cold chain.
Bacteria can enter these products, but what you want to prevent is it from growing to really dangerous levels. So one way to reduce the risk - it won't eliminate the risk - is to make sure you keep your bag lettuces refrigerated and treat them - you know, get them back in the refrigerator as quickly as you do your meat and poultry products.
Consumers aren't used to thinking about fresh produce that way, and I mean I don't refrigerate my apples and things like that or bananas, but for these bagged products, they're coming from far away. They've been through numerous processing steps. They're in a bag. So I think it just makes common sense that we need to keep the cold chain going if we're going to keep the levels of bacteria to the lowest possible level.
FLATOW: What about eating locally? We've been talking recently in programs about farmers selling locally, eating local produce.
Dr. DE WAAL: Local produce is great. It tends to taste fresher. It certainly has been around less long, so we're real supporters of locally grown produce, but it doesn't eliminate the risk. These bacteria can get on in almost any environment. In the organic regulations that USDA implemented a couple of years ago, they actually have mandatory controls for organic growers for the use of raw animal manure, but those same standards don't apply to traditional agriculture.
So we've got slightly more protections in place for organic produce, and locally grown produce is certainly something you should consider, but there aren't magic bullets here. This is really a wakeup call for the public that these products that we're used to thinking of as totally safe may harbor these same harmful bacteria that we watch for in our raw meats and poultry.
FLATOW: One last question from Michelle in Louisville. Hi, Michelle.
MICHELLE (Caller): Hi.
FLATOW: Hi there. Go ahead.
MICHELLE: Yeah, I'll try to be brief. Right now I'm a student in a bioterrorism course at Indiana University Southeast, where we learn about what can be used and how it can be spread. And the caller sort of asked one of the questions I had, so my other question is, you know, isn't this kind of a wakeup call? I mean wouldn't it be pretty easy for someone - I mean our food supply is very vulnerable to - for someone to slip in and toss some E. coli or fly a plane overhead and drop things like that. I mean how at risk are we to terrorist attacks on our food supply? And I can take my answer off the air.
FLATOW: Thank you. Caroline Smith de Waal?
Dr. DE WAAL: Yeah, thank you, Ira. Tommy Thompson was the former secretary of HHS, and he made this point a number of times, I mean once right after 9/11 and in his first testimony before Congress. He said that this issue of food bioterrorism keeps him up at night. It's - he really thinks that it's a serious risk.
That said, the government has made some investments in better protecting the food supply. But you know what, they're often robbing Peter to pay Paul. They're taking the inspection force and the policymakers out of their food safety area and putting them over in food defense. So we, you know, we're facing risks either way. You know, we need new investments here. We need to make sure that the government has the tools it needs.
And Senator Durbin actually has proposed this single unified food safety agency so that we can get all the resources directed to these problems in a risk-based way which we don't have today.
FLATOW: William Keene, any reaction?
Dr. KEENE: Well, I just wanted to add that it's important to note that in this outbreak there's no suggestion that this is anything other than an unfortunate natural event, that remains. The investigation is very much ongoing into the specific causes.
Intentional contamination is always a possibility. But it's - generally these things have much more benign explanations.
FLATOW: I want to thank you both for taking time to join us this hour. William Keene, senior epidemiologist in the Oregon Public Health Division Acute and Communicable Disease program, Caroline Smith de Waal, food safety director at the Center for Science in the Public Interest in Washington.
Thank you again for joining us.
Dr. DE WAAL: Thank you.
Dr. KEENE: You're very welcome. Transcript provided by NPR, Copyright NPR.