Science Friday - Does Time Exist, Elephant Seismology, Produce Safety. May 11, 2018, Part 2

Episode Date: May 11, 2018

How do you think about time? Most people experience it as Newton described it—as something that passes independent of other events, that’s the same for everyone, and moves in a straight line. Still, others have come to embrace Einstein’s view that time instead forms a matrix with space and acts like as a substance in which we are submerged. But physicist and author Carlo Rovelli has an even different approach to time. He’s working on a way to quantify gravity in which time doesn’t exist.  An adult African elephant can weigh as much as two tons. Their activities—walking, playing, even bellowing—might shake the ground beneath them. But new research finds that the signals from an elephant’s walk are capable of traveling as far as three kilometers, while a male elephant might be detectable a full six kilometers away with just seismological monitoring tools. This new research could protect endangered elephants from poaching. The E. coli outbreak linked to romaine lettuce has now spread to 29 states, and it’s claiming more victims. The CDC now reports that 149 people have been infected, more than a dozen have developed kidney failure, and one victim has died. In this segment, Ira talks with Rachel Noble, a molecular biologist at the University of North Carolina, about current methods of testing farm fields for pathogens like E. coli, which can take 24 to 48 hours to show results, and a DNA test Noble has developed that could cut that to less than an hour. Subscribe to this podcast. Plus, to stay updated on all things science, sign up for Science Friday's newsletters.

This is Science Friday. I'm Ira Flato. Later in the hour, we're going to talk about the growing e-coli outbreak in romaine lettuce and how farm food safety tests could use a bit of an update. But first, I want you to listen to a sound and guess what it is. Yeah, it does sound like a heartbeat, but it is not. It is the seismic sound of an elephant walking, the vibrations in the earth. Let me play it again. Really cool, huh?

That African elephant is. is the largest land animal still alive today, and more importantly for this story, they are the heaviest. They weigh up to two tons. So it might not surprise you to learn that we can listen to them in the shaking of the ground. And new research in the journal Current Biology this week

reports that earthquake monitoring tools are capable not just of detecting elephants from distances up to six kilometers away, but also distinguishing what kind of behavior is being heard. whether the elephant is walking quickly or even just roaring. And the researchers speculate perhaps this information could help us monitor elephants at risk of poaching, among other conservation efforts. Here to talk with me about that is a Beth Mortimer, research fellow in the Department of Zoology and University of Oxford in UK. Welcome, Beth.

Hi, thank you for having me on the show. And Tarye Nissomeyer, an associate professor of geophysics, also at the University of Oxford. Welcome, Tarye. Thanks very much, also for me. You're welcome. Beth, what sent you looking for elephant's seismology in the first place? So I'm interested in animals that use vibrations through materials for information. So some of my previous research has looked at spiders and how they use vibration through the spider web. So I have obviously looked at the other end of the size spectrum, but for the elephant, their spider web is basically the

savannah terrain. So it was interested in what the role that their physical environment plays on how they can use these vibrations for information. Tariya, have you ever tried to measure the seismological signal of an animal before? No, certainly not consciously. So this is certainly something that we did deliberately now. Seismic instruments essentially measure anything, you can imagine. But in this study, what we really tried to do is focus on this mammal behavior. How difficult is it to do this? How difficult. Describe the equipment you're using, how you set it up and how it works.

So the recording of vibrations works very much like what we're doing right now, it's talking to a microphone. So we just sort of put the ear to the ground and then listen through the waves as they properly get through the substrate. So wherever the source comes from, could be an earthquake, could be a volcano, an impact, a nuclear bomb, or in this case an animal, is the art and science. of seismology to disentangle this vibration in terms of where it comes from. I want to play the sound one more time, and then I want to ask both of you to sort of dissect it for me. Let's take one more longer listen. Wow, it sounds to me either like a heartbeat or a motorboat underwater. It does, yes. So what we did to generate this audio track was using this geophone, which measures the vibration through the ground,

basically generates exactly the same as a kind of audio track. But what I had to do for this vibration so that we could hear it is I had to increase the frequency. So the actual pitch is actually a lot lower. So think like really low bass that you can feel rather than hear. And then I also had to amplify this recording as well. So it's modified from its original form, but you can imagine it's the same techniques

that you would use to record, say, our, voices right now. And that was one single elephant we were listening to? That was one elephant walking past, which was recorded in the field in Kenya. Now, you found that these signals can travel three or even six kilometers, or that up to five miles away from the elephant itself. Is this something a human could feel just standing there? So, humans do have a sense of vibration. We're not very good at using it, though. So it's a lot better to use these types of geophones than to use our senses itself. But it doesn't mean that humans couldn't be taught to use these types of vibrations.

In terms of the long-distance scale that you're talking about there, what we were able to do with these recordings is basically get an idea for how much force the elephant was generating. And we put these into then computer models. So that quote of kind of six kilometers was using computer models. So under favorable conditions. So by that, I mean kind of low noise and on a sandy terrain, these high-force behaviors such as walking around

could be able to detect and be able to discriminate up to that kind of range. Now, Tarja, something I found really interesting and surprising is that vocalizations like that, you know, really loud male elephant roar we always hear, they could travel further than the mass of animals walking, do? Well, why is that? So this is something that is not entirely explained, but I guess the main answer is that these sort of very low frequency rumbles coupled really well to the ground. And additionally, the frequency range just propagates quite well into far distances through the substrate that we're looking at. I would say in general, this is not entirely surprising.

any sort of vibration that happens in any body, such as a large mammal, could in principle couple to the ground and therefore transmit energy. It's just something that we end up disentangling now. Matthew, say in your research that the same kind of signaling might be able to help us detect when, let's say, a bunch of elephants are stampeding, say if they're being harassed by poachers. Yes, so one of the main aims with this study was to basically use the seismological techniques that are used very widely to investigate some of the Earth processes, Tarias talked about,

and be able to detect and discriminate different types of vibrations that are generated by wildlife. So you mentioned the stampeding there. So elephants are obviously very well suited to this type of monitoring because of their large size, but they're also likely to generate the largest amount of force when they're running. So really, this technique is going to be best suited for measuring these panic runs that elephants do not do unless they have to. It takes a lot of energy to have a full out run for an elephant. So the idea is we could be able to use this technique to monitor these behaviors, which could be a sign of distress, and perhaps we could use that to help intervene when there might be some poaching threat. So you just hear them sort of massing and running.

Tarie, you know, I have an Apple watch and I put it on my night table at night, and it can detect when I'm walking across the room, just by my tiny... Could we not crowdsource this with electronic devices, our phones or watches or whatever to make sort of crowdsource all this detection?

I think it's a very good point, and it's certainly one that we have thought about and talked about as well. And something like that has actually has been tried in terms of earthquake detection as well. So in terms of wildlife monitoring and sort of a pragmatic approach

to deploying instrumentation in the savannah. I mean, it's a potential avenue, but I would think, realistically speaking, having hundreds of phones lying around in the savannas might not be sustainable in a long sense. I mean, lots of different types of wildlife walking around and animals are curious too. So I think having instrumentation safely deployed is really crucial.

Beth, if you, And Tarier and others can hear the elephants' footprints and also them bellowing. Could they, the elephants themselves, be signaling to each other? Yes, indeed. So we think that, well, starting with their vocalizations, you mentioned the bellowing there, and we've talked about these rumbles, these are certainly kind of signals that the elephants are sending out in specific social situations.

So they will have a specific type of vocalization. for a greeting, for example, or for an alarm signal. So they're certainly communicating with each other using these vocalizations. And obviously, part of that will go through the air, and part of it goes through the ground. And obviously, we're interested in that part that goes through the ground, really understanding how their physical environment plays a role in that. But yes, they're certainly communicating. Could you test that? Could you actually, you know, do your own little footprints and see if they respond?

Absolutely. There have been some excellent studies before that have used seismic recordings, so use these ground-based recordings, and played them back to the elephants. And we know that the elephants respond to these vibrations, and they can even discriminate in terms of who has sent that particular vocalization, so whether it was a known elephant or an elephant that they didn't know. And obviously, this is something that needs a lot more study in terms of understanding the sense. of the elephants and really starting to look at how that might change under different noise conditions, for example. I have to prevent myself from humming. I talk to the elephants song from, remember that one? What about other animal besides the elephants? Can we use seismic, you know, to detect and talk to them possibly? So this technique is going to be best suited for animals that generate a large amount of force.

So large land mammals, it's possible. that we can pick them up. The research that needs to be done is obviously looking at not only whether we can detect them, but whether we can discriminate between, say, antelope versus zebra or looking at different behaviors.

So that's certainly the next research project that needs a lot more data to look at that. Tarier, do you ever think, as a geophysicist, you'd be involved in tracking elephants? No, I mean, I've certainly had an interest in animals of all sorts of sizes

ever since being a child like many others. But I guess growing into the field of seismology, you sort of realize that vibrations just happen everywhere in the planet. And of course, it shouldn't prevent us from studying any sort of vibration rather than just earthquakes. So it's a natural trajectory, I think, that we're taking. That's interesting. Beth Mortimer Research Fellow in Zoology and Tarje Nissenmeyer,

Associate Professor of Geophysics, both at the University of Oxford and the UK. Thank you for taking time. to be with us today. Thank you. Thank you. You're welcome. And you can see some of their data, and you can actually hear it up on our website at

Science Friday.com slash elephants. We're going to take a short break, and then, again, maybe that short break just doesn't exist because, you know, we're going to talk about the concept of time with my guest, Carlo Ravelli, who says we don't have any time for anything because there's no time in the world. It's really interesting stuff. We'll talk about it when he gets here, because I'll really. ruin it before he does. Stay with us. We'll be right back after this break. This is Science Friday. I'm Ira Flato. How do you think about time? Well, if you're like most

people, you experience it as Newton described it as something that passes independent of other events, something that's the same for everyone. It moves in a straight line. Or maybe you've come around to Einstein's view of time as a substance in which we are immersed. But my next guest thinks about time even differently than that. He's working on a way to quantify gravity in which time doesn't need to exist. And he joins me now to talk about it. Carlo Rovelli is a physicist and author of numerous books, including his most recent The Order of Time. And I'll tell you, welcome to back to Science Friday, Carlo. Thank you very much. I, guys a pleasure you've been back here. I really enjoyed reading this because it just made my hair hurt in a good way.

Thank you. Let me take a stab at some of the things. things here and see if I'm getting this right. It's your belief as a physicist trying to understand the universe from a quantum point of view that time as we normally think about it is not a useful concept. We in the course of our daily lives think time exists. We're always running out of time. But you say that as a concept in physics, time, like that little T we use in calculating rate times times equals distance, really does not exist.

Would that be correct? Yes, that would be correct. Of course, it keeps existing in our daily life, right? We have 20 minutes or whatever to talk and this is not going to change. But it's not a good notion for thinking at nature of the fundamental level. It's a point. In fact, it's something that happened in a number of steps because we already have learned 100 years ago, I would say,

that our common notion of time It's not good for thinking about the world, right? Time passes at different speed for different people. We have learned that from Einstein, and recently we have clocks to actually measure it. We see that times passes faster in the mountain and slower near the sea. We have learned that the notion of present, a present all over the universe, is not well-defined. It's not objective. It doesn't really make sense if we look.

far away from us. So time has lost pieces after pieces, and my job is to study quantum gravity, and the question is what is a correct notion of time that remain valid in this large, in this

theory that is supposed to include everything we know about the universe. And I think that the answer is forget time. Forget time. Try to write equations without any time variable. We don't need it. We don't need it.

it. And it's far less dramatic and revolutionary than what it sounds. Because if you think for a moment, we really need time. I mean, I could say we started at, what is it, 320 and we're going to finish at 3.40 and I woke up this morning at 6 o'clock. But I could also say, I woke up this morning when the sun was there and we started when, I don't know, the hand of this clock here had this particular position and where that particular person moved there. So I could talk, mentioning only how things change one respect to the other and never referring everything to this time. We never see time, right? We see clock changing. We see sun moving. We see things moving. And I think that if we want to study the universe at its basic level where all things

move but in a disordered way, not together in a single time variable, it's better just to forget time and describe how the variables change with one another. Let me ask our listeners to chime in if they have time. How do you understand time? We're taking your thoughts and your questions about the physics of time and whether it exists at your number. And our number, 844-8255. That's also you can tweet us at Cy Fry. But there's so many questions. So you're saying that we don't, when physicists like you think about understanding the universe, they can write all their equations. And you're trying to do it in the quantum world. You can write all your equations that seem to work and you don't need to put that T of time into the equation. That's correct.

In fact, what happened is the physicists stumbled upon that. When already back in the late 60s, two American physicists, Bryce DeVitt and John Wheeler wrote the first equation that was supposed to bring together quantum mechanics and general relativity, today we call it the Wheeler-Deweid equation. That equation had no T, had no T variable, had no time in it. And this sparkled an enormous discussion that has continued for decades. What does it mean? after all, all the equations of physics before this one, the fundamental equation of physics, are evolution in time. Newton equation, Maxwell equation, Einstein equations were written as evolution in time.

Well, I think that things have cleared up. And it's not that we have a complete clarity about this story because we don't yet have a theory of quantum gravity on which everybody agree and that has been super, reported by experiment. So we have tentative theories of quantum gravity. But what we know, I think, and there's consensus about that, is that something dramatic happened

to our notions of space and time when we bring quantum mechanics in. And a number of people, me including, think that the easiest way to think about it is just to forget time. You see, let me put in this way, we think, you said at the beginning, quite correctly that we think time

a la Newton. Newton Newton gave us this idea of a time that flows uniformly all over the universe and that passes even if nothing happens like a big clock outside the universe that tic-tacks away the moment of time.

But this was Newton idea. It's not a completely natural idea for humanity. Before that, before Newton, the way people thought about time it's just the counting of things that happen. So before Newton, if you had asked people, what is time? They would have said, well, it's the days.

Day, night, day, night. You count the days, one, two, three, four. That's time. Or you count the oscillation of a pendulum. Or you count how much sands falls down in an hourglass. So time was considered as just a counting of change. And if you think time this way, which is a pre-Newtonian, the old way of thinking of time,

which I think is the most general one, that makes sense even if you don't have a preferred time variable, because you can count time in terms of days or in terms of months or in terms of oscillation of a pendulum, and each one might be different than the other one. They don't need to be in tune one with the other. So you can have as many time variable as you want, which is to say you don't have a preferred time variable in the world.

So time is basically a mental construct that we've created to advance our culture, let's say, so that we can all get to meetings at the same place at the same time, or something we've put in our head, but nature really has no use for it. Yeah, to some extent, yes. I think one of the main message of my book is that time is a complicated thing, is not a simple thing. We tend to think about time as just a thing. clear, compact concept, something that flows, the same for everybody, the past is different

from the future, and we all know what it is. But then when we studied, we realized that it's a multi-layered thing, and all its various properties come from approximation from different levels of reality, so to say. And in fact, a good deal of what we come called time is not really in the things in nature, but is the way our brain interact with nature. Time for us is a lot, memories, expectations, feelings, even the emotion of the time that passes, the anxiety of the future, the fear of losing things. Time for us is a complex superposition of layers that go from the emotional to the cultural all the way down to the physical

and physical there is little. There is some approximation which works well at our level. And if you want to discard all that and just look at nature at its most basic level, very little remains of what we usually call time. A lot of people want to talk about this. Let me start with a tweet.

Jimmy Morkin says, if we remove the notion of time, what happens to the idea that the fourth dimension is time? Well, in fact, if you do quantum gravity, you have to remove not just time, but also space.

So it's more dramatic than that. You see, Newton had not only this idea of time flowing, but also this idea of space as a container of the world. And Einstein understood that this container of the world is, in fact, gravity is a gravitational field, something that can move and can flex

as a sort of rubber sheet right on which matter moves, but is itself a sort of material thing. And if you look at the quantum aspect of this object, which is space or more precisely space, time, like all quantum objects is granular, is made by little chunks, individual chunks, grains. So we have grains of space, grain of time, grains of time, so to say,

which move probabilistically, because quantum theory tells us that things are probabilistic in the universe. So space breaks up in... Tiny little pieces of... Tiny little pieces, which are not in space, careful, but they make up space, so to say.

Wow. But so does that mean that there is no yesterday or tomorrow? There's just, I mean, you talk about philosophers, talking about there's only present, because that's all we can feel. But in time, one fascinating concept that you'd did bring up is entropy. Yeah.

That is one way of detecting some sort of movement or a change, right? Yeah. Talk about that. Yeah, that's another extraordinary surprising discovery that came out of physics. In fact, it started already in the 19th century, and it was clarified step by step. Namely, we have this sense that the past and the future are completely different, right? The past is fixed. is known, has happened already, is unchangeable.

While the future is open, it has yet to come, it can go in different directions. So past and future are completely different. We have memories of the past. We don't have memories of the future. We have pictures of the past. We don't have photography of the future. But then you study physics,

and it has been a surprise that the different, between past and future is much weaker than in our experience. In fact, all the basic equations of physics are invariant if we replace past with future. The only one, the only fundamental equation that distinguish the past from future, is, as you said, is the one that has to do with entropy, is the so-called second law of thermodynamics,

which says that entropy grows toward the future. Now entropy is, what you're saying, if I try to explain a little better, for me is that entropy starts low. The original universe was very low and then gets more disordered. It starts out very ordered and then gets disordered like my room does if I don't clean it up.

Exactly. So the entropy is a measure of disorder, right? It's just a technical way for saying how much disorder there is. And it grows, and it's not hard to understand why it grows because it's like your room. If you let the little child run in it, it doesn't put the things in order.

It's a disorder, everything. So that's one way to know which order things are moving by deciphering what the entropy is from one stage to another. Yeah, but what is surprising is that the only difference between the past and the future is this increase in disorder. There's nothing else. And that came as a shock for physicists, because the reason we have memories of the past and not the future,

The reason we remember the past and not the future. The reason we think about cause in the past and effect in the future, all that is nothing else that an effect of the growing disorder. And the open question for which we don't have an answer. In my book, I try to suggest one possible answer, but it's an hypothesis. I don't know if it is true. The question, the open question is why was the universe ordered in the past?

Okay, hang on, Carlo. I have to give a break. I want you to get time to tell how to answer. This is Amira Flato. This is Science Friday from WNYC Studios. Talking with Carlo Rovelli about his terrific new book, The Order of Time. I have so many dog-eared pages here, but go ahead. Finish your explanation. Yeah, the open question is why was entropy law in the past, namely why was the universe ordered in the past? And we don't know. It's one of the open mysteries in time. In other words, we don't know the real reason for which the future is different for the past.

It's one of the things that physicists are discussing. I suggest in the book that it's not really the universe which is ordered. It is our way of looking at it. You see, we see the sky rotating around us, right? But it's not the sky that rotate, it's us rotating. many things about the world we have understood by looking at ourselves and understanding that they're not properties of the world

but they're dependent on our perspective and perhaps even this, even the difference between past and future is a perspectival thing is something that depends on the way we look at it. You say in your book that we have we don't have a grammar to talk about the world without time.

Yes, one of that's a great difficulty of talking about time because we are stuck in our language. We have verbs which have past and the future and present, and we know for sure that that's not the way the university is organized. There are things which are neither past, no future, no present, or there are things that are past for me, but future for somebody who is in my future.

And we don't have a language, we don't have a grammar for that. We're a little bit, you know, 2,000 years ago people, understood that the earth is a sphere, is a rock, is a bowl. And they were all confused because they wrote things like, for the people down, up is down, and down is up, which make no sense at all. They were trying to rearrange the meaning of up and down. And now we understand that in Sydney,

up is different than up in Washington. I think we have to do something similar about time. We have to rethink what we mean by past, present and future. And do you think that the public will ever understand? Yeah. Look, the moment in which I hope it will come, we start to travel outside the Earth and we have people on Jupiter or Mars or perhaps even to other stars, we will realize that to ask what is happening now in the present on a distant star makes no sense. We will be used to the idea that people age differently if they move. away from one another.

So somebody is the same age. You meet a game as a different age. So we'll have to readapt our grammar for talking about time. We're going to take a break, and Carlo's going to come back and talk more about the great book, The Order of Time by Carlo Revelli. And a lot of phone calls coming in. Now, 8447-24-825. We'll get to those, some of those, and the tweet.

So stay with us. We'll be right back after this break. This is Science Friday. I'm Ira Flato, talking with Carlo Revelli. Rovelli, author of The Order of Time, a great book, great new book, Carlo. Thanks for writing us and giving us something to think about. In a few minutes, we have left to talk with you. Let's go to the phones.

Let's go to Lebanon, Pennsylvania. Dylan, I welcome to Science Friday. Hi, Ira. Thanks for taking my call. Go ahead. My question is for your guest, Mr. Rovelli. If you're taking the concept of time out of measuring gravity, which, if we're talking about standard physics, you use time 9.8 meters per second,

measure the rate at which something is falling. How are you quantifying gravity without considering time or space? There is a very close connection between time and gravity. They go together. That's a great discovery of Einstein. The speed at which our clocks move is determined by gravity. So that's a masterpiece of Einstein. 100 years ago he wrote this theory, and he told us how to do that. And in fact, the bottom line is that we should never talk about time by itself. We should talk about the time measured by a clock. And the theory tells how clocks move one with respect to the other, at which speed they go one with respect to the one with respect to the other.

So in a sense, we never measure time. We measure clock time, and we measure how the clocks move. in different manners and how the clock move differently from one another. Because the clock is moving, then its movement is influenced by gravity. A clock, well, the hand of the clock is moving and give us a reading, and the speed at which the hand goes depends on gravity very much. So literally, you take one clock a little bit higher, a little bit lower, and it goes a different speed.

So when you're in a massive gravity, like a black hole, then you just say time. stops? It slows down dramatically to the point of stop. So what we, if we could, just a matter of money, if we could go near a black hole and wait a little bit and come back, we would come back in the far distant future. Yeah. Okay, let's go to the phones to Misha and San Francisco. Hi, welcome. Hi, thank you. I love Mr. Rovelli's book seven, seven brief lessons in physics. Thank you. And one of, oh, I loved it. And one of the most moving parts for me was where you described all of what we take as reality as really being, as I understood it, sort of a complex mesh of energy.

And we view reality as being concrete, but really all we're viewing is this, this mesh that is ephemeral. And I'm wondering whether part of what you're saying is that time itself is woven into this mesh that you described in that book. Yes, very much so. Both in that book and in this new book, The Order of Time, I do various things. I try to describe what we have learned so far convincingly about the world, but also the kind of exploration that is going on now. and the way we think we're understanding the world. And this book is centered on the fact that as far as I understand, the best way of thinking of the world is not something there that changes in time.

Time itself emerges from this sort of very microscopical network of events. happening. And time is a multi-layered things that emerge step by step from there up. Do you think in your work to unify gravity with quantum, because that's really what you're trying to do, is it not? How long is that going to take? Because we've been talking about it for 100 years. Well, yes. I mean, the first who talked about that was Einstein himself. I mean, 100 years ago, he said, look, we have a problem. We have to find a quantum theory of gravity. But for most of these hundred years, almost nobody

was working on that. It's only in the last decades that have been a lot of work on that. The answer to your question is that we don't know. We have tentative theories of gravity. It's not that we're in the total dark, and we have some empirical information.

We don't know which theory is right and we are not sure when we will be able to find empirical information to confirm that. I think that's part of excitement, right? It's a scientific research as well as exciting. I'm sorry. Is it frustrating as well as exciting? Oh, yes. Well, scientific research is horrendously frustrating. It's a lot of things that don't work, right? Most of the things don't work. You throw away and you try something else.

Well, what people should not throw away and you should try is your new book, The Order of Time. Carlo Revelli, it's a great book, you know. It makes you think a lot. Thank you for taking time to be with us today. Thank you very much, Iroveli. He's an Italian theoretical physicist and the head of the Quantum Gravity Group at the Center de Physique, Theoretical, Al-Mal-Sei University. There you go. That's a finish segment.

We're going to go on to the next because we have time to do that. The E. coli outbreak linked to Romaine lettuce is growing. It's at 29 states. put half of its 149 victims in the hospital with symptoms like cramps, vomiting diarrhea, and even kidney failure, and now one patient has died, according to the latest report out this week from the Centers for Disease Control and Prevention. The outbreak is now nearly on par with a notorious E. coli spinach outbreak, if you recall back in 2006. And that day's view has made us wonder, is there anything new about how we test our salad greens for, disease? Are there ways we could modernize the way we do that to become less reactive and more

proactive about the food safety of our salads? Rachel Noble is here to talk about that. She's a distinguished professor in the Institute of Marine Sciences at the University of North Carolina in Chapel Hill, based in Moorhead City. She joins us by Skype. Welcome back to Science Friday. Thank you very much. I'm happy to be here. So how let's talk about the ABC's of how our lettuce is tested today. Give us a little thumbnail sketch. Well, the quick sketch is that we have some new legislation that has been put into place. It's legislation from the FDA, and it's called the Food Safety Modernization Act, which basically requires that water in the fields, particularly agricultural field water such as irrigation water and other waters associated

with the fields be tested for E. coli. And that's, but that's generic E. coli. It's important to remember that those are water samples that are taken. They're filtered in the laboratory. Those filters are then placed onto petri dishes, essentially, that contain a concoction of ingredients that are specific only to growing E. coli. And then we basically wait 24 hours for the majority of the test to count the number of E. coli colonies that appear on that plate. And that's the way that it's currently done,

but that is only for total E. coli. That is not specific. That's not a test that's specific only for the types of E. coli that can make someone sick. So if you take 24, 48 hours to test some lettuce in the field, they could have harvested and shipped that out by then, could they? That's absolutely correct. For a lot of raw products, produce, leafy greens being one of the most important, as we've seen in the past years. We have a situation where freshness and shelf time are optimized. Essentially, it needs to get to the grocery store and be available to the consumer in a pleasing way, you know, as a washed, rinsed product. But these are plants that grow very close to the ground, and they often have mixtures of sediment and sand that are. We're

can be found on that. You can see that just in your salad spinner whenever you spin the salad ready to eat it for dinner. And I know you have a patent on a different kind of test, a DNA test that takes much less time, correct? We have a test actually that was developed. Believe it or not, the patent was filed in 2006, the very year of the original outbreak that you just spoke of. And it took some time for it to be completely approved. But we've been trying to work to apply this to what we call produce wash. So that's the water that comes off of the leafy greens as it goes through that washing process that allows a bagged leafy green product to say triple wash ready for consumption on the front of it.

Would implementing this genetic test be more expensive to farmers and consumers? It's faster. It takes about 43 minutes for a result. We can get a result completely out in about two hours. And I would argue that the cost is slightly greater, but the way that we, the way currently that most, a lot of clinical tests are using molecular components these days, DNA RNA-based tests, that the costs have really come down and they're actually quite close to the costs of the other traditional tests. And that's because the traditional tests tend to be fairly heavy in the types of preparation to prepare the ingredients and the materials. So it's a little bit more expensive, but it's not vastly more expensive. And in my own thinking about this, of course, if you weigh the safety of people's lives

and shipping out something that might be contaminated, the cost may be worth it. That's exactly right. If people are interested in willing to support a move towards a more proactive system, we will, in general, as a public, as a community, we will need to absorb some of these additional costs, because if we want to be more proactive about the monitoring, currently most of the monitoring that is done is done out on samples from the field, but there's no way to sample every single bit of water

that comes in contact with a batch of lettuce. The wash process, you just don't know where to sample. You would have to take a lot of different types of water samples in order to describe exactly the type of contamination that any single head of lettuce had experienced. So how do you then sample the lettuce with a DNA test? Is it, can you get to a lot more lettuce? Well, we actually are just using the water that it's washed with

or the irrigation water in the field. So we have two choices. We can take a water sample out in the field, the water that's actually being used to provide water to the lettuce itself, or when it's brought to a packing house, basically what happens is that it's put on a belt and it's processed through a series of baths, and we sample those baths.

So, of course, it makes the most sense to only say. sample the very last bath because it doesn't make much sense to sample the very first bath that it goes through. So you can visibly see the amount of material coming off of the leafy greens as you watch them in these huge systems. I'm Ira Flato. This is Science Friday from WNIC Studios. Talking with Rachel Noble about lettuce testing. You know, every time we talk about whether it's lettuce testing, it's vaccination, whatever, and there are these other more efficient, better methods available that are never being used. Why don't we already use genetic testing across the board? It's pretty standard in the medical field. Why not agriculture? It is standard in the

medical field. In the medical field, you're often targeting a certain set of symptoms to someone who's actually come into the doctor. So you have a good feeling from that particular. person that physician what what you're already expecting to test for when we're out in the field it's very difficult because there's a whole range of organisms that actually could be causing a problem and so the the test that it has been put in place by the FDA that's now required due to new legislation is call calls for testing of generic E. coli and I think that's really a good start that's that's really the best way to go because there's no

possible way to test for all of the different types of E. coli or even other things that could get on lettuce and make people sick, like noroviruses or like other organisms like salmonella or Listeria. So it's very important that we get a feel for what might be out there from a more generic perspective. But the other answer to your question is that getting change and new rules adapted through the process of legislation and also So having different groups of people that are in the produce growing field, that's somewhat difficult because these are not rules that have been in place for a long period of time. And so these are requiring not only training of individuals, training for hygiene, for people

that are working out in the fields, but also training of a new mode of trying to test material using a different way. It just ends up being a little bit difficult, but I truly believe that we'll, we'll get there, it's just taking a little bit of time to make the jump from one to the other. Well, speaking of getting, are you not working with some farms to test the DNA method? How is that going? We have been working with some farms, and the interesting thing is that it works well. The data that we are able to produce, what we're doing now is we're trying to see how well

it compares to the existing methods. Those existing methods that take 24 hours, they are what are, they are, they are what are considered the gold standard. And so what we are trying to do is we're trying to hone our method of quantification, our way of counting the E. coli so that it matches exactly what's been done previously so that we know what to do with the data so that we don't get a data set that's apples and oranges. That's what takes a little bit of time. But that's a matter of just optimizing some of the details. It's not a matter of changing the basic components of the test that was patented. So can we convert our food safety system to be proactive instead of reactive?

I think that we can. I think that we can. I think that just the fact that people are more aware from media representation of outbreaks is a start. The FDA legislation is an excellent start. People are insisting that food safety is important. They don't care for the types of risks that are being posed. People are trying to eat healthier and they want to be able to eat raw foods. And so I think as this transition takes place the ability to translate these tests to, you know, a faster molecular test, it will take some time. But I believe that we're on the path.

And we also have some examples that show us that that path is vital. So I think that this is a transition that will take place. It's just a matter of time. Dr. Noble, thank you for taking time to be with us today. Absolutely. Thank you so much. You're welcome. Rachel Noble, Distinguished Professor.

and the Institute of Marine Sciences at the University of North Carolina in Chapel Hill. She's based in the Moorhead City. One last thing before we go. We're hitting the road next week to take the stage at Pittsburgh's Carnegie Library Music Hall. That is Saturday. May 19th, we will have roboticists, artificial intelligence engineers, and we're going to unveil a pop song written by a computer and performed by a live band, Pittsburgh's own townspeople.

Come join us. Yeah, that's a that's a, that's a, that's a, It's going to be Saturday, May 19th at Pittsburgh's Carnegie Library Music Hall. Tickets at Science Friday.com slash Pittsburgh. That's Science Friday.com slash Pittsburgh next Saturday, May 19th. BJ Leatherman composed our theory music, and if you, you know, we're on all the, every day now, Science Friday. You can listen to our podcast. You can ask your smart speaker to play Science Friday whenever you want to.

Facebook, Twitter, Instagram, all the social media. You can also send us feedback one of you'd like, SciFri at Science Friday.com. Have a great Mother's Day weekend. Happy Mother's Day to all of the moms out there in New York. I'm Ira Flato.