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Episode 3: Serving Up Science

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In this Episode

SwRI food chemistry expert and Lisa Peña discuss how Scheller’s team tests everyday grocery items for nutritional content and contaminants.

SwRI food chemistry expert Lorraine Scheller and Lisa Peña discuss how Scheller’s team tests everyday grocery items for nutritional content and contaminants.

What’s in our food? Scientists are chopping, grinding and pureeing their way to answers.

In this episode, we meet food chemistry expert Lorraine Scheller, a food lab manager at Southwest Research Institute. Learn how her team breaks down our food, both fresh and processed, to test for everything from calories, carbs and vitamins to pesticides, plastic and residues. After nearly thirty years of food testing, hear what Scheller has to say about organic versus regular produce, the best way to clean produce and what she thinks of our current food supply.

Listen now for some information to chew on next time you’re at the grocery store!


Below is a transcript of the episode, modified for clarity.

Lisa Peña (LP): Before you buy it, cook it, and serve it for dinner, your food goes through a lab for rigorous testing. How is food tested? What are scientists looking for? Is there a significant difference between organic and standard produce?

Hear from one expert, who has been testing food for nearly 30 years. She answers these questions and shares her findings on the state of our food supply. That's next on this episode of Technology Today.


We live with technology, science, engineering, and the results of innovative research every day. Now, let's understand it better. You're listening to the new Technology Today Podcast presented by Southwest Research Institute.

Hello, and welcome to Technology Today. I'm your host, Lisa Peña. We're about to learn a new meaning for the phrase "clean your plate," as we discuss the science that is happening behind the scenes to make sure the food that hits our plates is clean, fresh, and healthy.

So what is in our food? Do we really know? Even our produce can be hiding secrets. Our guest today and her team are experts at investigating our food supply, both processed and fresh foods.

Lorraine Scheller is a laboratory manager and food chemistry expert at Southwest Research Institute. And she's here to talk to us about determining the nutritional content of our food and detecting contaminants and residues in food. Lorraine, thank you for being here.

Lorraine Scheller (LS): Good to be here.

LP: Well, this is a topic that's really important for everyone. We want quality food in our pantries and on our plates. And it's always jarring when there is a recall or news of something unsavory in a product or produce.

So let's start with a really basic question. Well, basic for you, but not so much for me. What is food chemistry?

LS: Food chemistry pretty much runs the gamut from just simple ingredients to a fully processed food, vitamins, minerals, different types of fats, calories, sugar. Everything you would see on a nutrition label makes up our food. Of course, there's other added ingredients. There can be colors, and dyes, and fragrances, and flavors added to them as well.

LP: And is part of the chemistry evaluating those components?

LS: Oh, definitely. In 1990, the United States Government put the Food Nutritional Labeling Act [Nutrition Labeling and Education Act of 1990] into effect. so that all processed foods have the nutrition label. And you will see that any food product you pick up at a grocery store has that label on there.

LP: Yes, definitely. So how much is your team responsible for what we see on the food labels? How much of that information do you provide?

LS: We can test for all the components, from the cal. Well, calories is usually a calculation. But we can also do a laboratory experiment to determine actual calories, sugars, fiber, the vitamins, fat and water soluble vitamins. All those things we can test for and provide the information to our clients for the food labeling process.

LP: So I've often looked at food labels and I've seen the grams of fat, carbs, vitamins. How do you determine those numbers? What does a gram of fiber or a gram of a carbohydrate look like in the lab?

LS: Well, the carbohydrates are typically done either using chromatography, like HPLC [High Performance Liquid Chromatograhy], which you will look at specific sugars, sucrose, fructose, glucose. And then it's a little bit more complicated to get to the fiber. But it's all processes that we can do in the laboratory. We use gravimetric analysis and chromatography to get most of those numbers that you see on that label.

LP: OK, and those are just different analytical tools?

LS: Yes, exactly.

LP: All right. So here are some terms I'll understand. What foods do you test?

LS: We test pretty much everything, from produce, raw produce, ingredients, spices, to anything as complex as a frozen dinner or complete frozen dinner, granola bars. Just about everything you can think of, we can provide testing for.

LP: OK. So walk us through a standard testing process. What does that look like for, I don't know, let's say a fresh piece of produce, maybe an apple?

LS: OK. Typically for produce, the main thing we will test for will be pesticide residues. So they'll come into the laboratory. We will pretty much grind them up to a nice pulp, and we put them through an extraction process, which will pull out any pesticide residues from a certain. I can't say every pesticide, but we can see probably 200 to 300 pesticides in a single screen.

So we'll do an extraction, and that will be placed on different analytical instruments. Chromatography is the main way to do this. And then within less than 24 hours, we'll have answers to what pesticide, if there are any pesticide residues, in that piece of produce.

LP: And why are you looking for these pesticide residues in produce?

LS: Well, none of us want to be eating pesticides. That's just not palatable.


LP: Right.

LS: And there are certain laws and regulations that farmers have to adhere to. There are banned pesticides that you do not want to have used on your produce. A lot of them are similar to nerve agents. They'll attack the nervous system. So these are things we do not want in our food supply. So we'll test for those types of things.

LP: And these tests are happening before that food gets on supermarket shelves?

LS: Exactly, yes.

LP: So if it's not a fresh food, like a piece of produce, more of a packaged food, what does the testing process look like for that?

LS: It will depend on what the client needs, but it's a similar process. We get the product in. And for pretty much all foods, it's ground up fairly finely. And then a sample extraction with different solvents or different techniques will occur. And then that is run through analytical equipment to get whatever answers or whatever target analytes they're needing us to determine.

LP: So in packaged food, what types of contaminants or other information are you looking for?

LS: Well, mostly in packaged foods, a lot of it is quality control. They want to make sure certain nutrients remain in the food. They want to make sure that what the label says is truly what's in the food.

There are other times when a product isn't coming out the way that they expected it to, a quality control issue. And so we'll do some analysis to kind of pinpoint what the problem is. And we have nontargeted screening techniques that can look for pretty much anything. And we'll compare a questionable product to what it should be. And a lot of times, we can pinpoint where the problem is.

LP: So who are you doing this testing for? You mentioned some manufacturers and farmers. Are those your main clients?

LS: It runs the gamut, from farmers to manufacturers and processors, all the way to retailers. So we pretty much go from farm to fork and testing.

LP: I like that, farm to fork.

LS: Uh-huh.

LP: And these are all entities that want to ensure that they are following regulations and that their products--

LS: And they want to be sure that they're producing a quality product and selling a quality product.

LP: So you're also looking for allergens in--

LS: Yes.

LP: --packaged food.

LS: Allergens have become a big thing, especially so many people these days have food allergies. You think of peanuts. But there's milk, and eggs, and shellfish, and different types of allergens that manufacturers want to assure is not in their product because you do not want to have recalls because you have an undetected allergen in there.

LP: Yeah. For some people, that's a matter of life and death.

LS: Yes, definitely.

LP: And when you are testing for allergens is that also a similar process to packaged or fresh food?

LS: Yes. Yes, and there's certain protocols that we follow to do these types of testing. Most of them are published by the Journal of AOAC, I should say. They no longer go through the acronym, but AOAC. The FDA has some protocols in place. There's a Food Chemical Codex.

These all have methods that we follow, unless it's an unusual compound that a client needs us to analyze. And we will then develop the analytical methods to do that.

LP: OK, so you're looking for allergens. You're looking for nutritional content. You're looking for pesticides. Are there other contaminants that are at the top of your list there, that you're trying to weed out of food?

LS: There's a lot of different contaminants. Heavy metals is one. There's recently been in the news, arsenic in baby food or arsenic in rice. That's something that we can do. Lead contamination, those types of things.

Recently, I guess it was back in 2002, a Swedish journal came out with acrylamide, which is a potential cancer causing compound, that was being created or actually found in French fries, and potato chips, and baked goods. And this is actually a naturally created compound through the baking process. So we've worked with manufacturers, who have tried to develop ways to lower that occurrence, and so we've tested for that.

Right now, there's a recall on dog food concerning the vitamin D levels. They're too high, so that's something we can test for.

Also the state of California has a list called Proposition 65, which is their list of what they consider cancer causing chemicals. And if that's found in a product, it has to be labeled as potentially cancer causing. So there's a whole list that we can screen. Well, not screen for, but we can analyze for. Furans. Acrylamide is on that list. Caramel color, that's in beverages, is another one that we've done that's on that list.

LP: So what specifically in caramel color are you looking for?

LS: It's a compound called 4-MEI. It's not a natural product. It's a lab created product. And that has the potential to cause cancer, so they want to--

LP: So this is some scary stuff, kind of important that people would want to know about. So you're helping to kind of weed out what's in these products and hopefully get some good, safe food on our shelves. But how do some of these contaminants get into our food in the first place?

LS: Well, like acrylamide, it's through the baking process. Some of them are through food contact materials. A lot of our food is prepared with people using latex gloves. They're stored in plastics. And we have seen, in some products, that what's called phthalates is leaching out of these contact materials into the food.

And phthalates is something that's pretty much around us constantly. You think of everything that we have in plastics, from bottled water to even furniture, that we're exposed to constantly. And something that's been found in pretty much everybody's bloodstream.

So what the impact is long-term, I don't know if that's completely been determined. But it's possibly an estrogen mimicking compound or compounds. So I think it's something that we would want to avoid.

LP: So your clients are testing for this and want to make sure it's not in their product?

LS: They're looking mostly to see how much is actually going into the food.

LP: Because it's almost a given at this point that--

LS: Yeah, unfortunately.

LP: --there are many sources of it?

LS: Uh-huh. Even heating your food in plastic containers in the microwave.

LP: Yeah, I've heard not to do that.

LS: Yeah. Because that's what, it'll leach into your food, so.

LP: Yeah. OK. So there's a lot to learn here. One issue or one big, I don't want to call it a trend because I don't know that. I think it's here to stay. But a lot of people are interested in organic food and organic products. So in your lab have you tested organic food versus standard food? And is there a difference?

LS: We have tested organic produce versus just the regular produce that most of us buy, and there are small differences. You will find less pesticides on organic produce. For the most part, they are pesticide free. But that label kind of comes with an asterisk because they're free at the government assigned tolerances.

The tolerances for regular produce are a little bit higher. But in the 30 years I've spent testing produce, we find very little pesticide residues in our produce, which is great.

LP: Well, that's good news.

LS: Uh-huh.

LP: And that's just in standard produce?

LS: That's just in standard produce.

LP: So the organic produce is less, but since it's so minimal in standard produce, you're seeing less to none.

LS: Yes.

LP: And you mentioned earlier, we kind of talked about this off the mic. But that some of the pesticides that are part of organic fruits and vegetables just come from the soil.

LS: Yes. Unfortunately, some of these older pesticides have a very long half-life in the soil. And it's rare, but occasionally, we may see a low level of an older pesticide like a DDT or DDE.

LP: And that's just because of the soil --

LS: That's because of the soil.

LP: -- it was grown in.

LS: Yeah. The growers are adhering to all of the regulations, as they should. It's just a fact of the soil.

LP: And you mentioned a really good study about how to wash produce.

LS: Yes. We did a study years ago trying to see what consumers do in their home that can lessen their exposure to these residues. And one of the biggest factors was just a little bit of dishwashing liquid diluted in water and wash your produce. And it pretty much removed about 90% of those residues.

LP: That's great news.

LS: That's an easy way to get rid of that.

LP: And you would just wash it like you'd wash a dish?

LS: Exactly. Just rinse it with a little bit of dishwashing soap. Rinse it really well.

LP: A drop will do ya.

LS: Yeah, exactly. And you're good.

LP: All right. And you don't have to worry about any residue from the dishwashing soap?

LS: As long as you rinse it good, you'll be fine.

LP: All right. Residues on residues.

LS: Uh-huh.

LP: All right. So you did mention you've been testing food for 30 years now, or nearly 30 years, here at Southwest Research Institute. So what have been some of your most surprising findings over the years?

LS: Oh, I don't know. That's a tough question. I don't know if it's surprising. We have done some what we call nontargeted screening, and a lot of it looks at really minute levels of different things.

And it's surprising the amount of chemicals that are in our food, but most of them are natural products. Most of them are not harmful, but these little detections will sometimes give us a clue. We had a manufacturer come to us, and their product tasted and smelled different. And they couldn't figure out what it was. And so we--

LP: Not a good problem to have.

LS: No. And so we did some of this nontargeted screening and showed up several natural products. And they were able, just from that information we gave them, the chemicals that we saw, they were able to determine that it had been stored next to something that was offgassing and therefore transferring these smells and tastes--

LP: Ah. So it had nothing to do--

LS: --to their product. So it was a, yeah, it was an easy fix for them to go back. Unfortunately, they had to probably destroy a lot of the product that was stored that way, but at least it wasn't in their process.

LP: Yes. So in your time testing food, three decades now, have you noticed a change in our food supply from the products we used to test 30 years ago to say now? Are we looking at less contaminants, more contaminants? Where do we stand now versus then?

LS: I would say there's less contaminants in our food now. One caveat is that the technology we use now is so sensitive and so sophisticated that we're able to see extremely low levels of different things. So we'll find detections of things that are harmful, but they're at such low levels, is it really significant? And I don't think those answers have been determined yet.

So that's something to keep in mind when you eat your food. You hear things on the news. One of the big things was the Roundup. They were finding it in cereals and a lot of things that we eat. And Monsanto is one of those companies that have been sued as a result.

But those levels are sometimes below what the government sets as an acceptable level. Sometimes they're higher. But I don't think the science is there to determine is this going to be a really big issue for us or not.

LP: So that's good news.

LS: Uh-huh. Yeah.

LP: Levels of contaminants dropping, if even there at all?

LS: Yes. Yes.

LP: All right. So how do you feel about the state of our grocery stores these days? Are you pretty confident in what consumers are able to purchase? Because I'll tell you, sometimes we see the news, and you know you hear about different recalls and you hear about just kind of scary things happening out on the grocery store aisles. So what's your take on all of this?

LS: Oh, I think we have an extremely safe food supply. Manufacturers and farmers, and everyone involved in the process is very proactive about testing, making sure they are providing a good product.

The government is out there trying to protect the food supply as well as looking at imports. That's probably the bigger issue is imports and how well they're regulated. I have no concerns going into a grocery store and buying anything as much as I know about what's in our food.

The technology continues to get better. So we will be able to determine these things quicker, and faster, and at lower detection limits. So less of that contaminant will be getting out into the food supply.

LP: So after working with and testing food for so long, are there any foods that you absolutely refuse to eat?

LS: No. I like it all. I don't know. Green beans? I never liked green beans.

LP: But that's just a personal--

LS: That's just a personal thing.

LP: --preference.
LS: Yeah. No, I pretty much. I think everything in our food supply is fairly safe. I would just as a consumer, I listen to the news. I do my research.

LP: Stay on top of recent news.

LS: Yeah. Exactly. I think that's--

LP: Common sense.

LS: Yes, exactly. The bigger recalls are also microbiological, salmonella, and those are the ones you really hear about. But as far as chemical contaminations, I think we have an extremely safe food supply.

LP: So we want to make it clear. There is no reason to avoid green beans. You just don't like them.

LS: No. I just don't like them.

LP: That's awful. Maybe you need to get a great green bean chef out to prepare them for you?

LS: Yeah

LP: Or not. So what is your advice to your friends and family when they're out grocery shopping? Are you constantly delving out some tips for shopping?

LS: Well, I do. Number one is read the food label, as far to be healthy, of course. And listen to any recalls. Be aware of those recalls. And CDC has a wonderful website, that has those. They're available to anybody.

Like I said, food manufacturers and processors are extremely proactive in providing that information. They want to make sure they're giving a good product. So those are the two big things.

LP: So obviously we can't show the lab over the podcast to our listeners. But could you kind of walk us through your lab? How has your technology there changed? You said it's very sensitive now. It's really great at analyzing for these different contaminants and nutritional content. But can you tell us about some of the equipment or what we might see in your lab?

LS: We have-- I mean, there are some microscopes, typical, when you're looking for any kind of plastic, or metal, or something that's in the food. We do have those.

The majority of our work is done on chromatography instruments. The technology has advanced so that instruments that were extremely expensive 30 years ago are now affordable, so they're in our laboratories.

We use a lot of mass spectroscopy, which will take a food or a chemical and break it down into different components and pretty much provide you with a fingerprint of that compound, so that you know that's exactly what you're looking for. Where, in the past, we were just looking at a separation, but it was just peaks. We didn't have a true way to confirm that. Also, these mass specs gives you probably at least a 10-fold, if not 100-fold, increase in sensitivity from when I started working 30 years ago.

The nontargeted screening instruments, like I said, can give you an answer of a thousand or more chemicals in a single analysis.

LP: They're very precise.

LS: Very precise. Give you exact mass and mass spectra of the compounds. So you have a really good feel that that's what you're looking for, that's what you're detecting.

LP: And how many clients are you working with at any given time?

LS: Oh, it depends. I mean, it could be a handful. It could be a hundred. It just depends on if they call us when they need us. We have a good base of regular clients, but a lot of times we get calls from even consumer groups wanting us to do some testing. So it runs the gamut.

LP: OK. And how do you get the food that you test? Does your client provide that to you? Is it a better specimen off the grocery store shelf? How does that work?

LS: Typically, they supply us with the product. Occasionally, they'll ask us to go out and purchase it. They want to kind of see the variations in different sites. But the majority of the time, they're sending us the product.

LP: So any words you can leave our listeners with regarding food safety and the current state of our food supply?

LS: I think we're in good shape. Don't be too concerned. Don't stress out about what's in your food because more than likely any exposure is minimal. Don't stop eating produce. It's all good. If you feel better eating organic, great.

LP: And that's such good news because you are there picking this food apart and really getting down to the nitty-gritty of it. And seeing what's in it, what it's made of. So that's great. Yeah.

LS: It's a fun job.

LP: Yeah. And it's so helpful, obviously. Well, thank you Lorraine for your insight and for sharing your knowledge with us today. This is really an issue that's important to all of us. So thank you for being here.

LS: Thank you.

LP: Well, as we buy our food and shop for our families, it's comforting to know that experts like you are working to ensure that we are safe and healthy. So again, thank you for everything you do.

LS: All right. Thank you.

LP: And that wraps up this episode of Technology Today.

Subscribe to the Technology Today Podcast to hear in-depth conversations with the people, like Lorraine Scheller, changing our world and beyond through science, engineering, research and technology. I hope you'all join us next time.


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