Zachary Cartwright [00:00:00]:

I'm Zachary Cartwright. This is water in food. Today. My guest is Dr. Minto Michael at Washington State University. He is an assistant professor, and his lab primarily focuses on dairy microbiology and food safety. In the past, some of his projects have focused around water activity and how it relates to controlling pathogens in baked products and cooking processes, as well as in milk powder. Let's learn about some of Dr. Michael's previous work as well as his current research interests in this episode of Water and Food. All right. Well, hi, Dr. Minto. Michael. Welcome to water and food. Thanks for coming here today.

Minto Michael [00:00:35]:

Thank you for having me.

Zachary Cartwright [00:00:36]:

Yeah, we don't do too many in person podcasts, but we're excited to have you here in the studio. And I just want to, first off, talk about your role at Washington State University. What do you do there?

Minto Michael [00:00:48]:

So I'm an assistant professor of dairy science in the School of Food Science at Washington State University, and I have 70% research and 30% teaching responsibilities. In terms of teaching, I teach dairy processing and some introductory food science courses. And in terms of research, my research is mainly focused on dairy microbiology and food safety. But I do a little bit of dairy product development and dairy processing, lots of validation work. So basically I was hired at WSU to establish a strong dairy science teaching and research program.

Zachary Cartwright [00:01:25]:

And how long have you been there?

Minto Michael [00:01:27]:

Four and a half years. I started in August 2018.

Zachary Cartwright [00:01:30]:

And so you run this Dairy Microbiology lab. Is that a group of students or other professors who makes up that laboratory?

Minto Michael [00:01:39]:

So mainly students. So I am the main Pi PRI, principal, investigator, or director of lab. But all the hard work is done by my students, so it's my brain, but their hard work, sure. So I have PhD students, master's students, and undergraduate students. Right now we are trying to expand in terms of undergraduate students, but last semester we had total ten students PhD, two Masters, and six undergraduate.

Zachary Cartwright [00:02:09]:

And where did your own interest in food safety and dairy microbiology? Where does this stem from?

Minto Michael [00:02:14]:

Yeah, that's a good question. So my bachelor's degree is in food engineering. So as an engineer, I hated microbiology. So only thing I liked about microbiology was sacromycis cerevca, because that's the yeast you can make beer, beer with.

Zachary Cartwright [00:02:28]:

Right, right.

Minto Michael [00:02:30]:

So that was the only thing I liked about microbiology. But I love designing machines and working with machines and mathematics. But in 2007, I came to US at Kansas State University to start my graduate school, and the only place I could find assistantship was in Food Safety and Defense Laboratory. And I said, Well, I need assistantship to survive, so I'm going to do it. And I started working, and luckily I was blessed to have really nice professors. So my assistantship work was in Food Microbiology Lab, and we were doing lots of pathogen inactivation work with pet food that time. And for my master's research, I had another professor, Dr. Schmidt, and that was mainly focused on probiotics. So I started working in microbiology with good and bad bacteria at the same time. And within a few months, I just fell in love with microbiology. And I was very happy to give up my engineering and start working in microbiology and decided, okay, I'm going to get a PhD in food safety and microbiology and then focus my career in microbiology and safety.

Zachary Cartwright [00:03:37]:

And my background is kind of similar, actually. I started off in civil engineering at one time and got into biochemistry and then found wine microbiology. And then that brought me to Washington State. So kind of similar and still Sacramento surveillance. There's something about it. And I understand when you were at Kansas State University, some of your research focused or had a water activity component and you were looking at baked foods and pathogens. Can you describe that research a little and how you used water activity in those projects?

Minto Michael [00:04:08]:

Yes, sure. So as I said when I started, I started working with good and bad bacteria both together. So Dr. Randall Fevers, that was his lab, food microbiology lab where I started working. And the first project I was part was pet food. So what they were doing was they were putting some antimicrobial coatings and then they were drying that pet food product. And that was the period when I was not an expert. I was still learning how to inoculate products. What happens when you dry water activity decreases. So basically we were trying to see the impact of antimicrobials plus water activity to see how the bacteria are going to die. And that was the first project I worked related to water activity and microbial inactivation. But then when I started my PhD, one of the component of my PhD project was to see the heat resistance of chronobacter, sarkazaki and salmonelline milk powders. And I was doing that using regular heat treatment. But another important component was trying to see if we can use radio frequency heating to kill these pathogens in milk powders. And that was a major component when I actually started focusing on low water activity food products. So basically we were trying to see if we can use radio frequencies to inactivate these pathogens in milk powders. And then another important component that I started doing at that point was DNZ values, thermal inactivation, kinetics of pathogens in low water activity foods, but practically in anything. I can do that. But that was the first component. So I started with pet food, then moved into milk powders, and now I still continue doing milk powders. I also did one project with flour at K State. That was when, I'm not sure, I think it was around 2015 or so when we had an outbreak related to flower. That was E. Coli 26. E. Coli, one to one. So we wanted to see how long these E. Coli can survive in flower at low water activity. And we could find them after one year of inoculation. And I think there were samples left and even about one and a half, two years they were still present there.

Zachary Cartwright [00:06:21]:

And is it forming a spore or how is it lasting for such a long time in conditions that aren't favorable for growth.

Minto Michael [00:06:28]:

So these pathogens like Ecovice Salmonella, they don't form spores. So the spore formers, for example, bacillus, so what happens to them is when they find harsher conditions, they form spores. And spores are just dormant cells or in very simplistic way, they are like dormant eggs sitting in a harsh condition, waiting for nice environments to be encountered and then they'll start multiplying. But in non spore formers the mechanism is different. And I'm not the best person to explain that, but I can give you a basic understanding. What happens is when vegetative cells like Salmonella E. Coli, they encounter low water activity environment. So first thing they need to do is to protect their cell integrity. Because what happens is if you have high moisture content in the cell and the outer environment is dry, the moisture is not going to move from inside to outside of the cell and they're going to lose the shape form biochemical activities inside the cell. So first thing bacteria does is it start either importing solutes from outside, inside the cell or it will produce or generate some solutes inside the cell so that the osmotic pressure is maintained and the integrity of cell can be maintained. Other thing what bacteria does, it stops multiplying. If you don't multiply, you don't age, you can survive longer. Right? So what they do is they stop multiplying and they try to prevent their cells that are already existing, rather than trying to spend energy in multiplying. So they stop multiplying, they increase the solute content inside the cells so that they can survive that low moisture environment. But there are some other factors also. We are still trying to learn more about what is the exact mechanism, but these are two very basic and simple.

Zachary Cartwright [00:08:18]:

Mechanisms and it's crazy to me how fast a microorganism can multiply. And something I was just reading about is even if you have a single cell or a single pathogen in a square inch, if you leave it and it's under favorable conditions, it can turn into a billion cells in like 12 hours. So it's really interesting to see how water activity or how other hurdles can prevent that growth. When you did these studies, what were some of your major takeaways? Did you find a certain temperature time combination with water activity that was able to remove the pathogens that you looked at? What can the industry learn from some of the projects that you've done?

Minto Michael [00:08:57]:

Yes, that's a really good question. And the most important thing that comes to my mind when people talk about low water activity food is lots of time. They refer low water activity foods as comparatively safe food, right? That's what the perception is. And that's fine if you look at from one angle. But if you look like just having low water activity doesn't guarantee food safety. Because let's say if you have a low water activity food product like milk powder or your pre post workout powders, right, you hydrate and then you drink. But let's say if those low water activity powders are contaminated with E. Coli or Salmonella, those pathogens are still going to be there. They are not dying in low water activity food products. The only thing that's happening is that they are not multiplying. But when you hydrate those powders well, you are providing perfect environment for those pathogens to grow and then you will get sick if they multiply. So saying that low water activity products are inherently safer than the high water activity is not accurate. So the best way to make your low water activity food products safe is to prevent the contamination of food. So prevention is the best technique. You can make those low water activity food safer. And the other thing is the inactivation of pathogens in these low water activity food products really depends upon multiple factors. It depends upon water activity, but it's also going to depend how much fat you have, protein you have, sugar you have, because those components tend to protect microbial cells against thermal inactivation. So the composition of food matrix along with the water activity is a very important component. So these are some important things we should keep in mind when we're talking about safety of low water activity food products.

Zachary Cartwright [00:10:48]:

And how do you choose what method or what way to remove these microorganisms? How do you decide if you want to use heat or radio waves or high pressure or something else? What does that process look like?

Minto Michael [00:11:00]:

So, lots of time, if we are just doing testing our hypothesis, just thermal resistance, then we just use our traditional methods of heating in lab, we use water bath to determine DNZ values and thermal inactivation parameters. But let's say if we talk about practical applications, you have a food processing facility and you want to study some specific techniques, that's when we will actually just use whatever you want to use. So, lots of time. It's difficult to treat low water activity powders, right? For a few reasons. One is that you need to heat them at higher temperatures or longer time to kill those pathogens. And when you do that, you are actually destroying the quality of the product. This is true for flour, milk powders. So, lots of time what we do is to preserve the quality. We assist that regular heating with microwaves or radio frequency heating so that the overall treatment can be decreased. In terms of treatment time, the shorter is the time, lesser is the loss in quality. So that's when we'll say, okay, we want to preserve quality. Let's introduce radio frequency heating. Can we see if facilitating the heating with microwave is going to help? So it depends upon the desire of the company. They want to do it. But most important thing, based on my understanding, is we are very reluctant in terms of using irradiation. Right. I don't think scientists are, but consumers are. Sure, but if you want to kill pathogens and you still want to preserve the quality of your food, I personally think irradiation is the best technique to improve the safety of low water activity. Powders like milk or milk powders or flour.

Zachary Cartwright [00:12:50]:

I think you brought up a good point. It really depends on the goal or maybe the matrix or type of food. For example, I know that some processes, like high pressure processing, actually if you start with a high water activity above zero point 92, then those type of processes work even better at a high water activity. And that's a good point that with these powders, they're already so low that if you're going to introduce heating, then you're going to change that matrix and maybe cause browning reactions or unwanted changes in that food. So really depends on the matrix as well as the goal. I want to talk a little bit about your current research projects. What are you currently working on that excites you right now?

Minto Michael [00:13:28]:

I love dairy and I love microbiology, so I'm living the American dream. I've always wanted to focus my research on microbiology and have worked with multiple food matrices like beef, poultry, fresh produce, pet food, dairy, bakery. But dairy was always closest to my heart, and that's what I do in my dairy microbiology lab. Dairy and microbiology work with pathogens and probiotics. So I love doing what I do. But my lab is nationally recognized for two technologies. The first one is called hyperspectral imaging, and that's a technique where we combine regular photography with spectroscopy. So we can get two types of data, we get spectral data, and we get just the visual data from that technique. So what we are trying to do is we try to take photographs of either bacterial cells or bacterial colonies on the plate and try to identify if this is E. Coli Salmonella Listeria. So traditional microbiological methods will take somewhere from two to five or six days to give you a confirmatory identification of bacteria. If you have unknown you want to do traditional microbiology, it's going to take a few days to see whether it's E. Coli Salmonella Listeria. Using hyperspectral imaging, we can do that within few minutes. But right now we do have to do enrichment that would be somewhere from 18 to 24 hours. But once you have enriched sample, hyperspectral imaging has a capability of telling you what bacteria this is within few minutes.

Zachary Cartwright [00:15:02]:

Oh, wow.

Minto Michael [00:15:03]:

So this technology is very young in food safety. This technology is widely used in agriculture. It's used in our military to identify enemy tanks and other things. But in food safety it is very new. So there are very few scientists working on this technology, but we are trying to develop a system where we can actually use this for rapid identification. The second technology my lab is working on is called Ultra Fine bubbles or nano bubbles. So in simple terms, we introduce really minute nanoscale bubbles in food, mattresses or wherever we want to put in and use those nano bubbles to see if we can do something. So we use them in two ways. First thing we do is we incorporate nanobubbles in antimicrobial solutions, for example, chlorine water, acidic water or parasitic solutions. And then we see what happens to bacteria. And my research has shown that, that if we start incorporating carbon dioxide nanobubbles in these antimicrobial solutions, we can significantly increase the potency of the kill. So you can use the same concentration, but you're going to get way more log reductions. And the other thing we are using our nanobubbles is to promote the growth of probiotics. So this is something I'm still working. I have a good indication this will be working, but we don't have a confirmatory proof. But preliminary work shows if we incorporate carbon dioxide or nitrogen nanobubbles in milk and we ferment those milks, for example, to make yogurt or caffeine, then we can increase the longevity of probiotics in the product. Because all the yogurt or probiotic products you buy in the market, they're good as long as the probiotics in them are alive. If they're dead, then they're still going to be tasty, but you're not going to get benefits of probiotics. So this technology nanobubble has ability to increase the longevity of probiotics in the product and hence the shelf life of the product. So we can kill using nanobubbles and we can save using nanobubbles. So those are the things.

Zachary Cartwright [00:17:11]:

And when it comes to the the future of food safety, do you see either of these technologies maybe leading the way or causing the next big improvement? Or is there something else that we should be aware of that you know of?

Minto Michael [00:17:23]:

I'm pretty sure there are multiple things that can be the next big thing depending upon the researcher and the group we talk to. But based on my knowledge of hyperspectral imaging and nanovobal technology, yes, I do think they have great potentials. Hyperspectral imaging has just been studied. I'm not aware if they are implementing in food science right now or food processing. But hyperspectral imaging can be used for quality and safety purposes because let's say if you want to sort ripened apples from unripened ones, you can just mount a hyperspectral imaging on a processing line and that just simply can look at differentiate between ripened and unripened. We can use this technology to determine moisture content, protein content of food products. Just taking the photographs and again, for safety, we can identify what bacteria is present in a sample in few minutes. It has huge potential. Nanobile technology, again, has huge potential in improving the longevity of probiotics killing pathogens more efficiently. We haven't studied that, but hypothetically, in theory, nanobubbles may also have potential in improving the texture textural quality of food products. If we incorporate nanobubbles in products like yogurt, can it improve the overall texture or the body of yogurt? That is something you need to study. But there is a potential that these two technologies can be a huge implementation in future in the food processing area.

Zachary Cartwright [00:18:54]:

And if somebody listening wants to learn more about food safety or maybe join an organization that focuses on food safety, are there certain divisions or organizations that you're a part of that maybe you present to or that you organize with?

Minto Michael [00:19:07]:

Yes. So international association for Food Protection. That is IAFP. That is the best organization you can be a part of if you want to learn or contribute towards food safety. We meet every year, mostly during summer, mostly in America, and there are food safety folks, microbiologists all around the world attending that conference. It's a three day conference, and we discuss about new inventions, discoveries or regulatory things going on in food safety. That is the best way to learn about food microbiology safety and stay up to date. But other organizations like IFD Institute of Food Technologists, that is also really good because IFD is not focused on food safety. But food safety is an important component of IFD as well.

Zachary Cartwright [00:19:59]:

And IFT has lots of different divisions, and I'm actually a part of the quality management division. And just recently we decided that food safety will now be part of the quality division as well. So I think any of these organizations are a really good starting point to get involved, especially if you're interested in food safety. I noticed that you teach a couple of different classes at WSU, of course, dairy processing, but you also have one called Science on Your Plate, and that one just kind of caught my attention. I was wondering what that class is about and who can take that course.

Minto Michael [00:20:30]:

Yes, so I love teaching that class. So when I became a grad student, when I joined Masters, all I wanted to do was become a professor. And one of the most important thing I wanted to do was to teach an introductory food science course. Because people don't know about food science, right? You tell someone I'm a food scientist, so basically they'll think you're a cook or a chef.

Zachary Cartwright [00:20:51]:

Yeah, chef. That's what I get.

Minto Michael [00:20:52]:

And there is nothing wrong with that. But most of food scientists are very bad cooks if you know that they're not very good cooks. And that was the same thing, because when I never wanted to do food engineering, I wanted to do electronic engineering where I can write codes and build robots. But I couldn't get into that. It was a huge competition in India, lots of population competing for lots of big engineering courses, right? So I couldn't get it, but my father suggested like, hey, you should try food engineering. It's a new field. There are not many food engineers, and probably you can do really good. And I said, well, I didn't get what I wanted. Let me try food engineering. And I was pretty sure within few weeks or month, I'm going to switch the major. But luckily, I had a really nice professor who taught me Introduction to Food Science, and I realized, well, actually, I'm going to become an engineer. I will be a scientist. And I decided to stick with food science as my major. And that's one of the things I wanted to do when I become professor. I wanted to tell people what exactly food science is, and that's what I do in Science on Your Plate. So this is a U core course. That means common university requirement course at WSU. That means any undergraduate student who needs a science course can enroll in it. And since I don't get the science background students, I get students from management, apparel, designing lots of non science majors. So what I do is I teach science in a very basic form where students can learn about food science, but they're not scared of all molecular structures and microorganisms. So I tell them about basic chemistry of food, composition of food, basic microbiology of food, basic safety of food. Then we talk about misconceptions of food. Oh, it's okay if you drop your food on floor and count to five and you can still eat it and take it, right? Those kinds of misconceptions. What is organic food? Lots of time, people think organic food is really healthy and really good for you. And then I have to tell them, no, it's just a choice. Both organic and non organic is fine. It just depends upon you, what you want to eat, so all those kinds of things. And then we go to our WSU Creamery and have a tour there. And it's a really fun course. I just started teaching it in fall of 2021. And first time I taught, I had about 28 students. I taught it last semester, and it was 50 students. So I'm hoping to make this class to 200 students, and it is received well. I've gotten really positive feedback, and I really want to educate people on food science and remove lots of misconceptions about food.

Zachary Cartwright [00:23:39]:

And I agree. I think a lot of people aren't quite aware what food science is. And I have noticed, though, over the past even five years, that there are more and more food science programs and food science students. And so I think that there's growing interest in it, but I think the sooner we can reach out to more people and educate them about it, the more food scientists we're going to get out of it. If there happens to be any coughs listening to this. When do you teach this? Is this every fall? Every semester. And what is the course number?

Minto Michael [00:24:07]:

So I teach right now. I'm teaching it every fall. Okay, so every fall I teach Science on Your Plate, and the course number is FS 201. But as I said, if course get really famous and well accepted in WSU, then I do plan to take it from fall to summer. And if needed, I will start teaching it in spring. But right now it's offered only in fall. But I have also filed a paperwork for a lab portion for this course. So science on your plate lab. That would be FS 202. So if that gets approved, then I'll be offering a lab portion. And that won't be a required lab. It will be an optional lab where people who are in Science on Your Plate lecture can also take lab portion and they can actually work in food science labs. Basics of Food Chemistry microbiology will go to WSU, creamery, make cheeses, make ice creams. So the paperwork is done, but I'm not sure whether it will get approved or not. But if it gets approved, then we'll also offer the lab first.

Zachary Cartwright [00:25:12]:

Sounds fun. Sign me up. And if you need any guest speakers, if I can help you get to 200, I'd be happy.

Minto Michael [00:25:18]:

I'll call you for sure.

Zachary Cartwright [00:25:19]:

My last question is if there's anybody listening here who's maybe going into grad school or thinking about a PhD or Master's program, and they've heard about your lab, now how can they get a hold of you and how can they apply to be in your group?

Minto Michael [00:25:33]:

Yeah, they can just Google my name and they can find my phone number and my email address and contact me directly. So I always welcome grads new grad students. For now, what I'm doing is I'm not hiring any grad students right now because I have started some projects that I would like to finish. I would like to graduate my current graduate students, and then maybe by end of summer I plan to hire new students. Right now I am pausing in hiring grad students. I want to finish what I've started. But I do want to hire more undergraduate student right now. So I got some new funds just to support undergraduate student research. So if there are undergraduate students who are from food science or outside food science, they are more than welcome to contact me and they can work in my lab and they'll get paid well. And you don't have to be a food scientist to work in my lab. I have a person who is from mathematics Department working in my lab. I have a person from Microbiology department. I have an undergraduate who is undecided working in my department. So food science or non food science, if you're an undergraduate student, you need experience in lab, just contact me and we'll be happy to give you an opportunity. And by the end of summer, if you're a grad student and you are looking for a job, please contact me.

Zachary Cartwright [00:26:49]:

It'll be here fast. Well, Minto, I just want to say thank you so much for coming in. We really appreciate your time, and I think what you shared is really insightful. I'm really excited to see where your research goes, and maybe sometime down the road we'll have you back and you can give an update on and the imaging and so on.

Minto Michael [00:27:07]:

Yes, thank you very much for inviting me. It was really nice talking to you.

Zachary Cartwright [00:27:11]:

Yeah, thank you. I'm Zachary Cartwright. This is water and food. Find this podcast on Apple itunes, spotify or wherever you listen to podcasts.