Lisa Zimmerman  0:00  
Do you know [inaudible]

Nate Seltenrich  0:04  
No, I don't know if I've heard of that.

Lisa Zimmerman  0:08  
That's basically an [inaudible] program, and you can use it to talk and record at the same time. I use that for some interviews now, but I don't know how it is because I always got a link, but I think it's for free at the moment due to Corona.

Nate Seltenrich  0:33  
Okay, I'll make a note on that. But thanks for your flexibility. Yeah, so as I said, in the email, your article, your new paper was very interesting. And it's obviously timely in the sense that a lot of countries are paying increased attention to single use plastics, and a lot of manufacturers are, as a result, moving toward bio-based plastics, and the article that I'm working on is more linked to our... We're definitely aligning it with trends in disposable foodware associated with COVID. So there's some aligning trends here. So we're looking at basically increasing use of this disposable food packaging, what sorts of alternatives to traditional plastic and paper exists, and how they rate as far as in environmental sustainability, on the front end and disposal, and also looking at the chemical issue with various food contact materials. So, I was very interested to see this work that you did., and obviously, a lot of the general questions that I had are addressed in your paper, but I did want to just go over them a little bit more and hear your thoughts.

Lisa Zimmerman  2:21  
Yeah, sure. So what do you read? Did you read the press release? Or did you read the paper itself? 

Nate Seltenrich  2:32  
Well, I first saw the presentation that you gave at the packaging forum webinar and then that's when I reached out to you. And then subsequently, I had a chance to look at the paper itself. So I do have some; I'll just kind of run through some of my questions. 

Lisa Zimmerman  2:53  
Yeah, okay, so I know I don't have to give you like all the background information. So you already have specific questions since you have the background already. Okay. Perfect.

Nate Seltenrich  3:07  
So, one thing that again, I know you did address in the presentation, and it's also clearly stated in the paper, but I did I just want to ask about any way, which is; you say that individual variability is high from item to item. But at the same time, there were some trends in the various end points for toxicity or disruption associated with a few types of materials. Some were generally better and some were generally worse. I just want to ask if you have thoughts on why that is. Is that attributable to the sorts of additives used with those different feedstocks or material types? Or could there be...

Lisa Zimmerman  4:18  
Okay, so, maybe to start a bit before. As you mentioned already, so generally, it was really mostly dependent on the individual product, whether it was toxic or not, rather than the certain material type. But there were some trends. So for example, like the cellulose and starch-based materials, all of them, for example, induced in vitro toxicity, and a lot of them contained anti-angiogenic compounds which are endocrine disruptors and they also contain a lot of different chemical features. But yeah, those were a bit more... So, yeah, all of them were toxic, but then for the other material types. it's really dependent on the product itself. To get to your question with the additives, we can't really say where there's toxicity or this absence of toxicity comes from. When a product is toxic, it might be one chemical inducing the toxicity, or it might be the whole mixture which is responsible for it. And then it might be, when in the absence of toxicity, that they either did not contain potentially harmful chemicals; that we did not get them out of the material; but our testing methods; they are still in the material, but that we didn't extract these chemicals. Or it might be that they are only toxic for another end point. So there is not like a single thing to answer. There're many different reasons why, but we can't really say that they don't contain additives, or plasticizers, or whatsoever in general. We can only say that with the test we were doing, and the methods we were using, we didn't detect any toxicity, but we can't relate it back to any certain compound, especially since a lot of the compounds, we were unable to identify. It's not known what compounds these are. Okay, it was a long answer.

Nate Seltenrich  7:21  
No, that was very helpful, that answered another thing I wanted to ask, which I think I mentioned in the email, which, as you said, was whether this indicates that some of the products were not toxic, and you said that it does not which makes sense. So, one of the tables, I think it's S-7 (?) list; I think that's the one that has like the top 10 compounds from each article that were detected. And then there's another one that has, maybe six also has a long list.

Lisa Zimmerman  8:11  
Yeah.

Nate Seltenrich  8:12  
So those are good to reference. I mean, not that a lot of those names really make sense, generally to readers, and we don't always know what they are. But, but those are essentially the list of what you found, you know, boiled down to the most...

Lisa Zimmerman  8:36  
Prevalent.

Nate Seltenrich  8:38  
Yeah, so, a lot of those, we don't know what what they are, is that what you're saying? Or we don't know much about the toxicity of them on an individual basis?

Lisa Zimmerman  8:49  
Um, okay, it's different things. There are some substances that we can't identify with the technical methods we have, so it's technically not possible. And so you're like, I don't know which background we have. But, for example, when you do chemical analysis, you get a chromatogram. And you have a lot of different peaks. And then you compare these peaks with databases where the chemicals are listed, and then it might be that you don't find these peaks in the databases. So you don't know the name basically of the chemical. You know it is some kind of compound but you don't know what it is. So that might happen. On the other hand, some of the chemicals, they haven't been tested for toxicity yet, so it's not really known whether they are harmful to you or to humans or other organisms. Basically, since it's so many different chemicals, because we only identified some of them, right, we didn't try to identify all because there were way too many. And because it's really difficult and a whole lot of work when you trace it and set them all. But in general, what we rather want to point out is that the product we're using, whether they are bio-based, petroleum based, biodegradable or not biodegradable, they contain a lot of different compounds. And this mixture of compounds, we are not sure what is in there exactly; what is the individual toxicity of each compound; that's why we studied like the mixture toxicity of all the compounds we extracted out of one product. And then we can say, okay, we might not know all the different or all the individual compounds, but this one, the mixture itself, which is in the product, is potentially harmful. Because it's way too much work to to do it step by step; it's like chemical by chemical, and it's basically it's not possible. Does that make sense?

Nate Seltenrich  11:33  
Yeah. Well, and I think that's more the way that; I think in some European regulations, at least towards these mixture. I mean, that's kind of ultimately what matters anyway.

Lisa Zimmerman  11:47  
Yeah, yeah, that's the thing.  So I don't know if the regulations in the US are different, but also, I think, in the EU, at least; I think that's the same in the US, you don't test the single compound. In the EU, you only test single compounds you put in initially, but you don't test the mixture of chemicals you have in your end product. And then when you test only the single compounds, you know this compound might not be toxic, but it might be toxic when interacting with other compounds, because they might change or that may work or act synergistically. On the other hand, during the whole processing, these additional compounds get in the product from the procedure itself. So you can't even use; you only test the static substances, you don't uncover all the single compounds you have in your info-tech, and you don't cover the mixture. At least in Europe, that's how it's regulated, and I think it's some improvement to really assess whether these materials or the chemicals contained in them are safe or not.

Nate Seltenrich  13:17  
Yeah, now your tests don't necessarily say anything about the ability of these compounds to migrate during use into the food product or into the drink. Right?

Lisa Zimmerman  13:32  
Yeah. So what we did here is we extracted them; the methanol, which was a solvent, because our aim was to see what is the chemical composition contained in a product. And then that's an initial step because then we know there's something in there. And then in the next step, you would test; is that also released in our food, or our beverages? And we didn't do a migrate [XXX] and migrate study with these bioplastic materials or bioplastic products, but we did that on other products, and that's not published yet so I can't tell too much about it. But I can give you the tendency, or what we saw is that they have the potential to migrate but that's also again dependent on the; might be dependent on the chemical; might be dependent on the product becayse every the polymer structure for example, whether this chemical can migrate or not. But the tendancy we saw is a lot which is in the product also migrates. But we didn't cover that with that study here.

Nate Seltenrich  15:05  
Interesting. But that's an upcoming publication.

Lisa Zimmerman  15:10  
Yeah, hopefully that of next year. We published another paper last year, which was basically more or less the same methodological approach. But there we studied conventional petroleum-based plastics, and now we use these same products from the initial study to do a migrate study to see what is released, and it's going to be published.

Nate Seltenrich  15:48  
Now, have you looked at linings like PLA linings, which seemed to be a solution or a new approach that is being adopted by some manufacturers to be able to produce compostable products, like fiber cups and such that will have a PLA ining? Have you ever looked at those?

Lisa Zimmerman  16:17  
So lining is just for the word... it's just when it's not.. like you mean, not the whole product is based on PLA but just like one layer?

Nate Seltenrich  16:27  
Yes.

Lisa Zimmerman  16:31  
No, that was all based on PLA. It was was not multi-composed, multi-layer products. It might be that some are of the product blends, but that's different. 

Nate Seltenrich  16:55  
Well, based on the studies that you've done with, or this one, and then the migrate study. Do you have any, and I guess just your expertise in this area, in general, do you have any assumptions about whether all bioplastics are likely to contain some additives or non-intentionally added substances? Is it possible to have these like biopolymers without additional chemicals?

Lisa Zimmerman  17:33  
So yeah, so based on the study we're talking about right now, we identified at least 200 chemical features per product; at most of the times, there were a lot more. So that was the minimum, 200. And this is what we found. From the literature, and from what I read, is that additives are particularly, or might especially be, relevant for polymers extracted from natural resources, such as starch or cellulose, or for micro organisms, such as PLAs because they have limited physical properties. So for example, they have a limited thermal resistance or barrier properties themselves, like the polymers, and then you need to add other chemicals to make up for that. So, and I think it's really difficult; at least I'm not familiar with a polymer, which works with our additives. For example, if you think about biobased, PE for example, and there, it's the polymer, and the end is the same, the polyethylene. But here it is made from starch, for example, and it's not made from petroleum but the polymer isn't, and you produce the same. So you will need the same additives in the end. You want to have a certain ... it shall be, for example, soft, or it shall be durable or have a certain color. You want it to be protected from UV light. So to give it the properties you want, most of the times, that's why you add the additives and it makes sense that you also need the additives when you just base it on another polymer. Oh, that was a bit confusing. Did you get what I mean?

Nate Seltenrich  19:58  
Yes, so since you mentioned that PE, the polyethylene you found, those products in your study, were the least toxic or you have across the board. What would be the  potential explanation for that?

Lisa Zimmerman  20:24  
Yeah, I mean, we also found that in our other studies, that it doesn't matter whether it's bio-based PE or petroleum-based PE. So that was basically the same. And that explanations... I don't actually know; it might be, maybe it has, like, the polymer itself has better, more favorable properties; that you won't need some compounds to add. But there, I think you would need to ask the chemist actually. I'm not a chemist. A then again, here, there were some products that had a lot of chemicals in there as well. So it's really hard to say, okay, PE is always better, and so that's also really difficult to do. So there is no generalization possible.

Nate Seltenrich  21:46  
So to kind of get to that point as well, I think there's a comment or a note in the paper, saying that this study does demonstrate that there's at least some better alternatives out there, or some that display lower toxicity. But my understanding is that most companies don't, you know, and as you demonstrated here, with all the unknowns, that we don't necessarily know what exactly they did. So, if another company wanted to replicate a low toxicity approach, would they be able to do that, given that these are kind of proprietary products and materials that don't; in other words, they're not going to go openly share their recipe so to speak.

Lisa Zimmerman  22:49  
Yeah, that's completely correct. Yeah, it's a lot of non-transparency. So the companies, they don't communicate which chemicals they use, and because otherwise you could; if they make their composition available, then you can take the one product without toxicity as a best practice example and see which chemicals are used in that product or which, and then you could design other products in the same way, but since it's not openly available, it's really difficult. I bet it would be definitely a step forward to increase the transparency and to increase the communication and to make the data available. 

Nate Seltenrich  24:10  
Let's see, one last thing maybe and I think this just gets back to the additives again. The paper also knows that toxicity was less prevalent and potent in raw materials than in final products. What would be those raw materials and is that again, a matter of additives to the raw materials, essentially, is the final product more toxic?

Lisa Zimmerman  24:41  
So yeah, the raw material would be pre-production pellets. And then you use these pellets to, for example, to extrude(?), I think that's the English word, a foil out of it. And then you use the foil, for example, to make a box. So, like the pellet is just the first step, and then you process it to the respective product you need, and then in these steps of processing, probably chemicals are added, for example plasticizers to make it more soft. And then you use probably might use catalyzers to speed up the processing. So, yeah, during the processing steps, and probably a lot of the chemicals I added in the different steps. And I mean, what you could do, if you follow the green by design approach is that you say, okay, let's see if you have like raw materials,, and we see that's without any toxicity, then we do the next step. And then we analyze this product, is this without toxicity. Then we know everything would be added and has no health implications, or some negative effects. And then you could proceed like that. But it's also like a really time consuming approach.

Nate Seltenrich  26:29  
Yeah, to make sure that each step is receives a certain level of safety.

Lisa Zimmerman  26:38  
Cause you guarantee the safety of each individual, intermediate product; to rule out that you have some intermediate adverse toxicity, and then it's probably also the end productions, but that you identify the step where the toxicity gets in, maybe the other way around.

Nate Seltenrich  27:05  
Okay. This is really helpful. Thank you so much. I really appreciate it. You mentioned, or said, maybe a chemist could help with some of these questions you. I don't know how deep I'll be able to go into that. But do you know of any or any, you might recommend any who could reach out to?

Lisa Zimmerman  27:37  
Yeah, I work together with one on my project. I see him on Monday. So I could ask them on Monday, or I could also like, just send him an email and put you in contact? I think he I don't know how time constrained he is at the moment. But I could just ask him and then send you to contact if that's fine.

Nate Seltenrich  28:05  
Sure. Yeah. That would be great. Yeah, I would just be curious, basically, what a little bit more about, like the, as he said, the properties of some of these polymers that might lend them or cause them to require certain types of additives? You know, basically that question. Yeah, I see. Yeah, I would appreciate it if that's possible. We'll see.

Lisa Zimmerman  28:31  
Yeah, I'd write him an email right away, but usually, it's easier to reach them personally.

Nate Seltenrich  28:38  
That's fine.

Lisa Zimmerman  28:40  
It might take until Monday until he responds.

Nate Seltenrich  28:46  
Okay. Well, thank you very much again, I know it's a Friday afternoom but I appreciate your time for helping me understand this a little bit better.

Lisa Zimmerman  29:00  
Yeah, thank you for being interested in it. And I don't know when... do you think you're gonna publish the article

Nate Seltenrich  29:13  
It's going to be in about a month? It's going to be a rather large package, as I said, because it's looking at sustainability and chemicals and trying to evaluate specific materials. And so it's going to have a number of different components and it should all be out in early to mid December, and I will make sure to pass it along.

Lisa Zimmerman  29:39  
Yes that was going to be my question, and and if you have any STEM questions, you can also just write me to let me know.

Nate Seltenrich  29:50  
Great. Well, thank you, Lisa for your flexibility. Thank you. Bye