IRA FLATOW, host:
This is TALK OF THE NATION Science Friday. I'm Ira Flatow.
Just when you were getting over that Taco Bell food scare, comes a news today that Marion County health officials - that's the name in Indianapolis - are investigating a case - a reported case of 160 people who claimed they have become ill after eating at an Olive Garden restaurant in Indianapolis last weekend. They are investigating it and not sure what the origin of the so-called or possible food poisoning is - they're taking samples.
But this comes, surely, right after - now, we were just getting ready. Taco Bell lovers no longer thinking they need to run for the border, that is, their state border. Several of the fast food stores in Northeast, they were closed back in a Taco Bell food scare. Now they've been given the go ahead to reopen after the Centers for Disease Control said that an outbreak of a deadly strain of bacteria linked to that restaurant was over.
And they're not quite sure what the cause of that outbreak was. First they said it was onions and they say now it's probably dirty lettuce. They went through the initial test of onions that came back positive then they then did a more thorough test of the onions that showed that the onions not to be the culprit.
There have been several prominent cases of food-borne illness this year, mainly linked to produce. But CDC statistics say that overall, from 1996 to 2005, the incidents of almost all major food-born illnesses - that incidents, including E.Coli infections, has declined.
So for the rest of the hour we're going to be talking about food safety and agriculture, including a really interesting report in Consumer Report. Consumer Reports, that's on the January issue of Consumer Reports, that says over 80 percent of all the chicken we eat is contaminated with salmonella or campylobacter, a potentially deadly bacteria. And that consumer reports expert will be joining us later to talk about it.
But first, we're going to talk about the veggie side. And if you'd like to join our discussion, our number is 1-800-989-8255, 1-800-989-TALK.
Michael Doyle is a professor and is director of the Center for Food Safety in the College of Agricultural and Environmental Sciences at the University of Georgia in Griffin. He's also a consultant on food safety issues and he was recently retained by Taco Bell to evaluate his procedures. He joins us from NPR studios in Washington. Welcome back to the program.
Professor MICHAEL DOYLE (Center for Food Safety, University of Georgia): Well, thank you.
FLATOW: You're welcome. Robert Gravani is a professor at the Department of Food Science and is director of the National Good Agricultural Practices Program based at Cornell University - big agriculture center there in Ithaca, New York. He joins us from a studio on the Cornell Campus. Welcome to SCIENCE FRIDAY.
Professor ROBERT GRAVANI (National Good Agricultural Practices Program, Cornell University): Nice to here. Thank you, Ira.
FLATOW: Both of you, let me get first your reactions to this Indianapolis story. Familiar with it? It sort of just broke open this morning. Maybe heard anything about the 160 cases of possible food poisoning?
Professor DOLYE: I first
FLATOW: …at the Olive Garden?
Professor GRAVANI: I first heard it from you, Ira.
Professor DOYLE: And I first heard it from you, Ira, also.
FLATOW: Well, we're at the cutting edge too far. It's going to cut back from the cutting edge. It's been reported in all over the Internet this morning. And then I think the crush of news from foreign news has sort of blocked it out. But the local media in Indianapolis are reporting it also. AP is reporting it and the health officials there, as I say, in Marion County, have gone and then collected samples, and stool samples - trying to figure why 160 people became ill or say they became ill over the weekend. But is this the kind of thing -and now we're seeing all these cases lined up - are we living in times where we just, Michael, we have to get used to this now?
Professor GRAVANI: One of the good things that we have going for us in this country is that we have an excellent reporting system that's in part led by the Centers for Disease Control as well as the state and local health departments in detecting and following up on these cases. And our Food and Drug Administration and USDA are also very important in this process. So we have that going for us. But with these good surveillance systems, they're going to also detect more and more outbreaks that perhaps in the past would have not been recognized.
FLATOW: Now, as a consultant retained by Taco Bell, do you expect you're going to find out what caused those illnesses?
Professor DOYLE: Well in many cases are outbreaks - the true vehicle or source is not always identified. I think the Centers for Disease Control now has a pretty good lead based on some of their case control studies to link lettuce to this outbreak. And it's - frankly, lettuce is not a surprising source because we have had several outbreaks in the past associated with fresh lettuce.
FLATOW: Bob Gravani, what's your take on all of this? Where are these things coming from?
Professor GRAVANI: Well, I think if you look at the issues, lots of things are changing. Certainly, the organisms are changing, getting more virulent. We as hosts are changing. A large proportion of the population is immuno-compromised, more susceptible to some of these organisms - got lots more elderly people, lots more who are in chemotherapy, who are transplant patients. Pregnant women certainly fall into this immuno-compromised category, and certainly young children. So those are the groups that are specifically vulnerable to some of these organisms that cause food-borne illness.
And certainly the environment that we live in is changing as well. So with all these changes going on, certainly, we're going to see some of these issues surfacing. And prevention is the best strategy. We really need to look at what's going on on the farm so we can prevent these organisms from getting from their reservoir to the crops that we grow and harvest and then eat raw.
FLATOW: Let's talk about that. What is going on on the farm? What's going on on a farm?
Professor GRAVANI: Well, lots of things. We need to think about what some of the potential sources for contamination are. And certainly irrigation water is a concern. I know lots of these companies do not use animal manure or even composted manure, but some farmers do. We're certainly concerned about that. Wild and domestic animals certainly are potential sources of contaminants. Farm worker, health and hygiene, the people who harvest our crops.
Many of them are packed in the field and they receive obviously no heat treatment to go to market. And they get into our homes and we need to kind of think about that aspect of it. Harvest equipment and containers transport equipment, just unsanitary handling throughout the course of the food chain, the food system. Certainly, water that's used in processing. Ice, flume water that brings a number of commodities from the farm into the packing house where they're washed and sorted, grated, etc., and packaged.
And just a maintenance of the cold chain throughout the system. So there's lots of places that problems can occur but we are certainly are focusing on the issues related to on-farm. What is happening on the farm that's causing these organisms to get from where they normally live, their reservoirs, to the crop itself and cause these outbreaks to occur?
FLATOW: Mike Doyle, are there silver bullets, are there tech - you know, I'm looking for the technology solutions to all these problems, this laundry list that Bob was talking about?
Professor DOYLE: That's really the difficult question. The answer is simply because we eat produce fresh. We like to eat it uncooked and so we don't have the traditional treatment that is applied to many foods before they're consumed, and that is heating, which is very effective in killing these harmful microorganisms. So we have to come up to come up with alternative approaches.
Chlorinated water is typically used to wash the produce in processing plants, but we now learn that this is not a fully effective treatment for killing harmful bacteria, should they be present. So we're going to have to do a lot more in terms of developing methods that are truly effective to kill harmful bacteria. But as Dr. Gravani said, we need to go all the way back to the farm, and make sure that we can do the best we can on the farm, to prevent the contamination from occurring in the first place.
FLATOW: Where would be the best spot on the farm and - to start, that will yield the greatest result?
Professor DOYLE: Well, from my perspective, it's not just one spot. Irrigation water is an important consideration. We have to think through where do these harmful bacteria originate. And for E.Coli 0157, it's largely carried by animals that are what we call ruminants - its include cattle, and goats, and sheep - deer.
FLATOW: So the irrigation water comes off the farm and goes through the droppings and goes to the lettuce, let's say.
Professor DOYLE: Well, droppings somehow get into the irrigation water or get directly onto the soil through fertilizer or some other means. But somehow, the manure from these animals have to get into the field to cause this degree of contamination.
FLATOW: Bob, do you agree?
Professor GRAVANI: I agree totally. Prevention is the key. Our mantra in the Good Agriculture Practices Program is, food safety begins on the farm. And prevention is the strategy, because once these organisms attach, it's extremely difficult to remove them. We might reduce them by a few log cycles but you're never going to reduce all of them. And with organisms like E. coli 015787, as few as 10 cells can cause illness. So, you know, we've got a question that needs to be answered.
FLATOW: We've talked many times on this program about eating local, instead of having it shipped across the country. Would eating locally possibly prevent you from getting sick, or is it just a big a risk, eating local?
Professor GRAVANI: Well, that certainly has a lot of appeal, and we want to support sustainability and the local agricultural communities. But clearly, these issues can happen anywhere. I mean, we see cases were people are on smaller operations maybe using manure or maybe using compost.
So large or small, the issues are the same. We need to think about these good agricultural practices and reduce microbial risks on the farm.
FLATOW: 800-989-2855. Let's go to the phone cause lots of people have questions. Let's go to D.B. in Nevada City, California. Hi.
D.B. (Caller): Hi.
FLATOW: Welcome to SCIENCE FRIDAY.
D.B.: Hi. I'm a veterinarian. I'm a science-trained veterinarian to take (unintelligible) of all of our food. And we could fix all this rather easily with food irradiation, cobalt-60. It does the same things that canning and applying chemicals like chlorine. We pasteurize all our milk. We do all things after it leaves the farm, after it leaves the garden, to protect our population.
Food irradiation is already approved by the FDA. Any reason it isn't used?
D.B.: Other than hysteria.
Professor DOYLE: That's a very good question and a very good point. And part of the reason is, first of all, the irradiation process has to be approved by the Food and Drug Administration for specific applications. But even if it is the product that results after the food has been irradiated has to be desirable. One wants to eat it. It has to have good quality characteristics…
D.B.: Much more desirable than canning, for instance? It makes almost no change to the food - much less than canning, much less than curing.
FLATOW: Though I think - but are we saying here that it's a public perception of danger problem?
Professor DOYLE: Well, that's part of it as well.
Professor GRAVANI: Yeah, that's certainly part of it. I think some of that stigma has been removed by the fact that we have had irradiated ground beef on the market for quite a while, and then off for a little while, back on again. And those products seem to be selling very well with consumers who may want to have their ground beef cooked to a, let's say, a less intense temperature than what we would normally recommend if it were not irradiated.
I think Mike is absolutely right…
D.B.: All the hysteria about e-coli and other bacteria - that's not the only one, but e-coli gets much PR.
FLATOW: Hang on, D.B. We're going to get an answer. Why don't we use more irradiation then?
Professor GRAVANI: Because, first of all, I think we need to look at the capacity and get geared up if we're going to do that. And as Mike said earlier, each of these commodities have to go through an approval process. And I'm not sure, right now, what the quality issues are regarding, let's say, leafy greens in the irradiation process. I know they have lots of work going on in the USDA labs in Wyndmoor, Pennsylvania - on sprouts and a number of other leafy green commodities.
And we would need to look at that, plus the cost factor, plus - do we have the capacity to, if it was approved, to irradiate this many pounds of, let's say, leafy greens.
FLATOW: Let's go to Kaye(ph) in Flint, Michigan. Hi, Kaye.
KAYE (Caller): Hi, Ira. Thank you. I'm not a scientist, but I love your show. Because every time I hear that it's TALK OF THE NATION on Friday, I know I'm going to learn something. I'm just a consumer. I've got a question. What do Americans expect? We want our food to be cheaper and cheaper, and faster and faster. This is kind of - we're getting what we deserve, almost.
FLATOW: Gentlemen, would it add a lot of costs to irradiate, let's say? Is she right?
Professor DOYLE: Well, whatever additional processing treatments are applied will indeed add costs. But, you know, the meat industry has gone through major changes over the last decade, and have applied additional treatments that have not greatly increased the cost of ground beef and chicken.
And so we can come up with treatments that are effective. I think that will work. But to your point about, hey, what's going wrong here? There's a variety of reasons that we're seeing more and more contamination. And produce in particular is a concern because we normally do not give it a heat treatment before we eat it. And so as we eat it fresh, we're at the mercy of the farmer in producing a safe product.
FLATOW: We're talking about food safety this hour on TALK OF THE NATION: SCIENCE FRIDAY from NPR News. I'm sorry, go ahead. I didn't mean to walk on you.
Professor GRAVANI: It's okay. And recognize this too that these commodities are grown in the outdoor environment. There's birds flying over, there's animals walking through. Those kinds of things need to be taken into consideration.
Now do we advocate contaminated produce? Absolutely not. And I think if we look at the organizations and agencies, the academic institutions that are really spending a lot of time and energy and resources on this problem, we've really got to get to the bottom of it because it is a concern. We want people to eat more produce cause of the health benefits.
But clearly, consumers are concerned about the recent food-borne illnesses.
FLATOW: Thanks for calling, Kaye. 800-989-2855 is our number. What about having more inspectors? Do people inspect the fields where these things are growing and take samples to see if the, you know, if there's contamination?
Professor DOYLE: Inspection is done, often routinely, depending on the ranch. But it's more from the quality standpoint, that is - is there weeds growing in the field and these sorts of issues. And not so much from the food safety perspective.
FLATOW: So no one is testing a leaf of lettuce here, spinach there to see if E. coli or whatever's on there?
Professor DOYLE: Not too often. But the reality of it is, is you have a large field of lettuce, it may be difficult to pick up an E. coli if it's in an isolated area. So testing isn't the only solution, Ira. It can be a part of the equation but certainly not the only solution.
FLATOW: But you might be able to pick up who the, you know, where the problems are located. You know, who's not taking care of their farm, as much as the other person who might be.
Professor DOYLE: That's a possibility.
Professor GRAVANI: One of the things that's sort of a mantra is that you can't inspect-in quality or safety. You've got to really build it in. And the way to do that is to look at all those aspects that we talked about earlier: the potential sources and sites of contamination, and go back and tighten those up so you can reduce the likelihood that these passages are going to get from their reservoir to the crop.
And I think that's where, you know, companies' quality control people, their food safety folks and possibly some third-party auditors or inspectors can address some of those issues. Let's tighten those things down where we can.
FLATOW: All right. We're going to take a short break, come back and add more to the pot that we're cooking up here. We're going to bring on an expert from Consumer Reports about their latest study showing how infected chickens are with harmful bacteria. So stay with us. We'll be right back after this short break.
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FLATOW: You're listening to TALK OF THE NATION: SCIENCE FRIDAY. I'm Ira Flatow.
We're talking this hour about food safety with Michael Doyle of the University of Georgia, in Griffin, and Robert Gravani who is at Cornell University in Ithaca.
And now we're going to talk about a really interesting research article showing up in this January issue of Consumer Reports. News about chicken that you eat -the raw chicken. Researchers taking a survey of 500 samples of grocery store chicken found that 83 percent harbored campylobacter or salmonella bacteria, both of which can make you very sick.
That percent is a huge jump. That's up from 49 percent in 2003. Forty-nine percent 2003 - 83 percent 2006.
Joining me to talk about it is Jean Halloran. She's director of food policy initiatives for Consumers Union, which publishes Consumer Reports. And she joins us from her office in Yonkers, New York. Welcome to the program, Ms. Halloran.
Ms. JEAN HALLORAN (Food Policy Initiatives, Consumers Union): Hi. Thank you.
FLATOW: How bad is it buying raw chicken these days?
Ms. HALLORAN: Well, you have to be very careful. You really need to assume that the chicken that you buy is contaminated, since eight out of ten packages that we tested had these disease-causing bacteria on them.
FLATOW: Were you shocked at how much it almost doubled in three years?
Ms. HALLORAN: We were quite surprised. The most of the problem is due to the campylobacter bacteria, which is the one that's gotten very much worse. The salmonella had stayed about the same since our previous tests. But these were the worst results yet, since we started testing chicken in 1998.
FLATOW: You know, the U.S. Department of Agriculture spokesman called the report junk science - criticized your methods. How do you respond to that?
Ms. HALLORAN: Well, I think this may have a defensive reaction on their part, because one of the things that we've called for is for USDA to do testing for campylobacter and to establish a standard for it. I think they maybe don't want to believe that there's a problem there. But we have a statistics department here that designs our testing. It's thoroughly designed to be a random sample and we have full confidence that our results are valid.
FLATOW: Well, considering that they don't test at all for campylobacter, you're 500, they're zero - sample size.
Ms. HALLORAN: Yes. And in addition, our results agree with their results on salmonella where they do their own testing. It's only on campylobacter, where they have no testing, that they seem to think that there's something wrong with our methodology.
FLATOW: Other studies have found a much lower incidence of contamination, around 25 percent. Why is that?
Ms. HALLORAN: Well, that's really only one study that found such a low level. Most other studies have found higher levels. For instance, some FDA testing in 2004 found 60 percent contamination. This particular study that found the 25 percent, looked only at chicken taken from processing facilities who volunteered to be in the study.
So it's possible that it was the better facilities who volunteered. And also, if you know that the test is in progress, you really may put your best foot forward on that day.
FLATOW: How do the…
Ms. HALLORAN: Our samples…
FLATOW: I'm sorry.
Ms. HALLORAN: It's just that our samples were taken from supermarkets chosen randomly across the country in 23 states.
FLATOW: Yeah. We're familiar with your testing methods. How does the chicken get contaminated and in such high quantity?
Ms. HALLORAN: Well, it can happen at any step in the process. And so the control methods, while they're not rocket science, they really require a lot of vigilance. It starts right at the chicken coop, where bacteria can come in with water or with food or with the workers going in and out. They have to be very careful there.
And once in the chicken coop, it can spread rapidly among the chickens. And we have chickens being raised in mass production facilities where there's 20 or 30 thousand of them together. So it's doubly important to be very careful about the situation there.
The other big place that contamination can occur is at the processing facility, because these bugs tend to occur in the digestive tract of the bird. So when they're slaughtered, there's the chance that fecal matter can get onto the chicken and even get spread around in the washing process. So that must also be handled be very carefully.
FLATOW: Oh, I found that a very interesting observation you made about cleaning up and preparing - when people do this in their kitchen, let's say, and the people think they are doing something the right way and they're doing it exactly the wrong way - in that when they try to clean up an area with a sponge, they're actually spreading the bacteria around.
Ms. HALLORAN: Well, the best thing to do is to - well, you have to be careful all the way along. Make sure the chicken doesn't drip on the other things in the refrigerator and that you use a separate cutting board and knife for it, and then just put that in the sink and wash it right away. And make sure, when your chicken is cooked - and it must be thoroughly cooked, no pink parts - that when it's - when you are done cooking it, make sure you don't put it back on the plate that it came off of.
FLATOW: Oh right. If it was a raw chicken plate, if you are out in the…
Ms. HALLORAN: That's right.
FLATOW: …it's a perfect barbeque situation. Put the chicken on the plate. You put it back on the barbeque grill. It's done. You put it back on the plate it came in on.
Ms. HALLORAN: That's right.
FLATOW: Oh, gee. And you figure…
Ms. HALLORAN: Wrong.
FLATOW: …wrong, or maybe - Michael Doyle, and you work in agriculture, what do you think of this report?
Professor DOYLE: I think it's a really interesting report. The good news is that over the last five years, CDC surveillance studies have revealed that there has been about a 30 to 40 percent reduction in human cases caused by campylobacter, of which poultry, in the past, has been identified as a primary vehicle.
And I think one of the - if I were to design the study that was done by Consumer Union, would be that they would enumerate - determine how many cell numbers of campylobacter are present.
And the data show that there has been a tremendous reduction in the number of campylobacter that are present on the chickens, which fits with what we call the infectious dose - how many does it take to cause illness. And so, there has been positive strides in the industry. Maybe the prevalence - there's still a large number of chickens contaminated - but not with the levels that would be needed to cause human illness.
Ms. HALLORAN: Well, we're still concerned about the most vulnerable populations, you know, the very young and very old. And, obviously, smaller - lower levels can affect those groups more seriously. But, Mike, do you know at what stage that 30 percent drop happened, like between which years? It's my understanding that most of that drop occurred before 2000 and that it's slowed down a bit since then.
Professor DOYLE: That is correct. It has occurred over about a five-year period of time. But these reductions also have occurred over a five-year period of time.
FLATOW: 1-800-989-8255. Let's go to the phones - to Ben in Detroit. Hi, Ben.
BEN (Caller): Hey. How is it going?
FLATOW: Hi there.
BEN: Hi. Hey, I was - I wanted to call in because I actually work as a food safety inspector for a third party company. And I'm honestly surprised that we don't see more cases of food-borne illnesses. Some of the practices I see in the places I go into would just make your head spin. People like soaking raw meat in stagnant water to thaw it out, and just not cleaning their surfaces, cross contamination issues all over the place.
And part of our job is to also, you know, train the folks working there and I go back time and again and nothing ever changes, and I'm just surprised that we don't see more of it.
FLATOW: Could we - folks be seeing - could people get sick and you have mild cases of it and think it something else?
Ms. HALLORAN: Of course. I think most - that's what happens most of the time. The cases that are reported in these outbreaks are ones where you're sick enough to go to the doctor, and the doctor actually identifies the bug that you've got. And that's a very small percentage of the total of something like 76 million cases of food poisoning that CDC estimates happen every year.
FLATOW: Mm-hmm. What would you recommend that the government get involved in, in regulating how the chicken are being processed?
Ms. HALLORAN: Well, they absolutely need to set a standard for campylobacter. They can't just go on ignoring it. They had thought that by controlling salmonella, you would also get this other bacteria. But our data clearly shows that the other organisms are not being controlled by the same methods that they are using for salmonella. So they have to have one of these programs.
FLATOW: We reported at the top of the hour the Olive Garden outbreak. They supposed - we're not sure what actually happened in the Indianapolis - 160 people are coming down with food poisoning. Surprise you at all?
Ms. HALLORAN: I'm not stunned. It does seemed to be quite a succession of events in the last six months. But as your guests were saying before, especially with produce, you have to go back to the source and start trying to take some steps. I - we would suggest that you need to go even further and look at this E.coli 0157, where it's coming from the cows, because it - up until 1980, we didn't have this problem of this particular nasty E.coli in cow manure.
And we think there should be some attention given to whether it can be reduced or even eliminated in cows, so that it's not - we're not having the problems of - problems with a pasture next to a field and the field becoming contaminated.
FLATOW: Actually, the number as we even - as we speak has gone up to 250 people in the Indianapolis. Michael - Bob, what do you think about the feeding of the cows? The cow problem and what happens inside the stomachs of cows?
Professor GRAVANI: Well, we also have done research in this area in trying to come up with ways to reduce the carriage of E.coli 0157 in cattle, and so far, there's no silver bullet out there. But there are promising treatments, such as vaccines, and feeding friendly bacteria that will out-compete the E.coli, and, perhaps, even certain feeding practices, may be affective.
So, we're learning more about it but we don't have a silver bullet yet. But I can tell you, that producers are looking at this very seriously, and also processors have done a lot of research to learn that contamination of the hide with manure is a very important way in which the E.coli 0157 gets on to the meat during processing.
And so, they are taking gigantic steps in trying to remove E.coli from the surface or the hide before the animal gets into the processing plant. And that's having major impact. Over the last few years, we have seen major reductions in the incidence of human illness caused by E.coli 0157. And also, we have seen major reductions in the occurrence of 0157 in ground beef.
So the beef industry is making great strides in fixing this problem, not entirely, but doing a great job minimizing it. The produce industry on the other hand, as we're seeing, has a problem.
FLATOW: We're talking about eating healthy - eating, without getting sick this hour on TALK OF THE NATION: Science Friday from NPR News.
Of course, you don't have vegetables that are wallowing in their manure on their way to being slaughtered. That's one of the things that veggies - lettuce doesn't do.
Professor GRAVANI: There's another issue that's important in the poultry area, too - that consumers can do to protect themselves - and that is certainly cooking the product thoroughly ,as Ms. Halloran mentioned a few moments ago. But how do they know it's cooked thoroughly? They really need to use an accurate thermometer to check for doneness, to make sure that it isn't pink inside.
And they are certainly concur with the cleanliness of the kitchen before, during, and after preparation of chicken. But it can go back one step farther. When you're buying chicken at the supermarket put it in a plastic bag so that the juices don't drip on other products that are put in the same grocery sack with the chicken.
FLATOW: It's almost like you have to have a special processing area for the chicken itself, do the chicken. It's like being in a laboratory or in a hospital, you know. Maybe have gloves on so you don't contaminate anything else, and then sterilize everything around you.
Professor GRAVANI: Well, it is -
FLATOW: - You can't - go ahead. I'm sorry. You can't process. You can't work on a chicken and a salad at the same time, is what I heard from the consumer reports article.
Ms. HALLORAN: Yes. It's absolutely true. And, you know, we think it's, unfortunate, really - actually that our chicken has come to this, and that we can do a lot better. But for the time being, that's what the consumer must do.
I'd like to make one other point in terms of the 0157 discussion, and the caller has suggested irradiation as a solution. You know Consumer Reports, a couple of years ago, did some tests on irradiated burger, and unfortunately, we found two things. One was our sensory panelists compared its taste to burnt hair. They found it less appealing in taste than the untreated burger.
And the other thing was that even the radiation didn't completely eradicate bacteria in the meat, so we still advise people to cook their burgers, especially if they are immune compromised.
So we feel like it's really not a solution. It's much better to try to control these problems at the source, so that you're not having to treat contaminated food products.
FLATOW: Well, you have about 30 seconds left. One of the solutions we had heard about was having cows fed grass instead of being fed the animal food that way. It changes the chemistry but in their stomachs.
Professor DOYLE: There were some early studies to suggest that might be a factor in reducing 0157 in cattle. But other studies have not been able to reproduce those findings. So it's still a controversial issue, and it appears, you know, in Scotland where they have some of the highest prevalence of E.coli 0157 in cattle. Those animals are largely grass-fed, so the epidemiology doesn't support that finding.
FLATOW: All right. We'll be following the story and other food outbreaks. I want to thank you all for taking time to be with us today.
Michael Doyle, professor and director of the Center for Food Safety in the College of Agricultural and Environmental Sciences, University of Georgia, in Griffin. Also, Robert Gravani, professor of the department of food sciences and director of the National Good Agricultural Practices Program at Cornell University. Also, I want to thank Jean Halloran, director of Food Policy Initiatives for Consumers' Union, which publishes Consumer Reports.
Thank you all for taking time to be with us. Have a good day.
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I'm Ira Flatow in New York.