Cuisson Sous Vide

Jennifer Holland: Welcome to Short Talks from the Hill, a research and economic development podcast from the University of Arkansas. I’m Jennifer Holland. My guest today is Jennifer Acuff, assistant professor of food microbiology and safety in the Dale Bumpers College of Agricultural, Food and Life Sciences Department of Food Science, and a researcher and scientist with the Arkansas Agricultural Experiment Station, which is the research arm of the U of A System Division of Agriculture. Jennifer earned her bachelor’s degree in biology from Abilene Christian University and a master’s degree in food microbiology from Kansas State University, as well as her doctorate in food safety and microbiology from Virginia Tech. She has research experience in food safety, working in areas related to beef, ready-to-eat foods and low water activity foods. Jennifer, welcome to Short Talks.

Jennifer Acuff

Jennifer Acuff:  Thank you.

JH: So, to start us off, tell me a little bit about your research and why it’s important to food safety.

JA: So, ultimately my research is meant to be applied food microbiology for the purpose of reducing recalls and outbreaks, so that’s going to help improve consumer health and also reduce costs associated with recalls for food industry members. So, my research focuses on low water activity foods. Sometimes they’re referred to as low moisture foods, so things that are dry, like fruit – dried fruits – nuts, spices, powders, any of those categories of foods – that’s where my research area primarily focuses. But it’s always meant to be integrated with serving the food industry members and trying to increase awareness about food safety issues for the food industry and for consumers.

JH: So, tell me what you think everyone should know about food safety.

JA: I think one of the most important things to recognize is that food safety is for everyone. Everyone eats and everyone makes decisions on a daily basis and judgments about what they’re putting into their bodies. And so a lot of students will come through my class at the end of their college career and learn about food safety and food microbiology, and I get a lot of comments at the end thinking, “I had no idea that this field even existed, but it’s so relevant.” So one of the primary points of my class is just, you know, not a lot of people are going to leave food microbiology and become a food microbiologist, but they will be a more educated consumer. And so I think encouraging people to dig into learning about the food and the safety of it: understanding how contamination of foods happen – what’s a normal and acceptable risk – that enables them to perform their own risk assessments each day to decide what risks are worth it. Food is never going to be sterile; it will never be risk-free. We wouldn’t like sterile food – it wouldn’t taste very good, to be honest. But if you can know what kind of risks might be associated with certain foods and decide if you’re willing to take certain risks – because you really love raw cookie dough or maybe you really enjoy medium burgers – that might be a risk you’re willing to take. But it’s important to know what the risks are, so that you feel in control and in power. This is especially important for people who are going to leave and maybe be caretakers of children who might not be able to make those decisions themselves, or perhaps you’re going to take care of elderly parents who are entering an immunocompromised state, and they might need some help making those decisions. And so being aware of what you’re putting into your body is obviously important from a lot of aspects, but especially for food. And the thing we want to encourage is people to be educated on food safety and not necessarily rely on the pseudoscience you might get from uninformed armchair experts, I guess.

JH: Okay, so what would be some resources that you would guide people to, you know, if I did want to research food safety on my own?

JA: So, I would say Cooperative Extension is a really great resource. So, part of my appointment here at the University of Arkansas System is Cooperative Extension. And so we kind of act as the bridge between research and the public, and we’re trying to serve the consumers of Arkansas. And so, every state that has the state funding and has a Cooperative Extension program is going to be a bridge between, you know, food safety researchers who are the experts in the field and then the consumers. And so, Cooperative Extension is a really good resource for some of those questions. You can also always look to USDA and FDA for resources. Sometimes news articles can be helpful, but a lot of times news articles don’t necessarily have all of the background information to provide enough context to the problem. And so, I always recommend that people take a single piece of information with a grain of salt. If you can find, you know, the same piece of information in a very popular media source, and the USDA and the Cooperative Extension fact sheet, that’s probably a reliable fact. And so sometimes that’s really hard for individuals to spend a lot of time doing, so part of my job actually is responding to people who send emails to say, “I have a question about this.  I’m not sure if this is safe,” or, you know, “I’m making this home canned good – is it okay if I do it in this manner?” And I actually can do the research a little bit faster to send to the resource and save some people some time on that. But just feeling empowered to look from multiple sources, I think is very important.

JH: And I understand you’re working on an industry grant-funded project to investigate salmonella contamination and dairy powders. And this seems especially timely with the recalls we’ve heard about related to infant formulas. Tell me a little more about your work in this area.

JA: Sure, so, we’ve been doing some research on this for a couple of years, and a lot of different researchers have looked at different angles of dairy powder/milk powder safety, because part of the problem with low water activity foods is it’s not really an environment or a food matrix that would support the growth of foodborne pathogens like salmonella or E.coli or listeria monocytogenes. But, if those pathogens manage to contaminate the food product in that desiccated environment – that lack of water, lack of moisture – they can survive for extended periods of time, and it can be very difficult to remove them from the foods. And we oftentimes think of dairy powders as ready to eat, right? We put them into a bottle and mix it up as infant formula, or it goes into a protein drink, or it’s a food additive of some kind, but it may not get an additional processing step from the consumer. And so, it’s not like you see a disclaimer on the label that says, “Cook thoroughly before consuming,” like you would with a raw meat product, and so that means that these foods have some unique challenges because the food industry has to take a lot more responsibility. So the research we’re doing is trying to figure out how can we help these food industry members make the product safer when it’s in their control, and that’s tricky because with these low water activity foods, thermal processes might degrade the quality of them, right? So, if you think about a dried fruit product, for example, you don’t want a roasted raisin – so, that’s the same problem we have with all low moisture foods – is it’s difficult to find interventions that reduce contamination problems that occur, as we saw with the infant formula outbreak.

JH: Describe one of the experiments that you would do in your lab to test this.

JA: Yeah, so, for the dairy powders, one of the things that we’re looking at is, is there a thermal process that is low enough temperature-wise that it doesn’t degrade the quality of the powder but is effective at inactivating pathogens like salmonella. So we actually put salmonella on non-fat dried milk and milk protein concentrate that we then put into these thermal discs. They’re small individual discs that are made of stainless steel or aluminum. We submerge those into a water bath and then treat them for a certain period of time, pull out the discs, remove the powder aseptically, and then essentially quantify the reduction – the kill of salmonella over time. And so, in this we’re able to decide, you know, what thermal process is sufficient at reducing or inactivating salmonella populations if they’re there, and we’re also able to check on the quality. So, are the processes that are sufficient in inactivating the pathogens, are they also going to be acceptable for consumer quality?

JH: So, there’s been an increase in popularity of sous vide cooking. For those who don’t know, tell us a little about what this cooking technique is and how it influences the research you’re doing.

JA: Yeah, sure. So, sous vide cooking is a French cooking technique that means you’re cooking something under vacuum. So, these are oftentimes going to be vacuum packaged meat products that are then submerged into a water bath and treated at low temperatures and for longer time periods. So this results in a really nice texture, and it retains flavor better, retains moisture better, and so… It used to be that this was not really a process used widely by consumers or smaller restaurants because the equipment was pretty expensive. You had to have a water bath, something that could keep the temperature and monitor it and keep the water bath going at the same temperature for a long period of time. And now they’ve created equipment that is very affordable. You can buy it at Walmart. And so a lot of consumers are starting to do that. And so, whenever consumers have access to that, they are very creative in developing recipes, posting them online, but we don’t always see a lot of safety awareness of these things. And so, because they’re cooking at a lower temperature, we need to check and validate the cooking parameters to see that they would be sufficient in killing microorganisms – pathogenic microorganisms – if they’re there. So, we have safe cooking temperature recommendations from USDA that say you should cook ground beef products to 160/165, right? But if you’re cooking something in a sous vide technique, you’re not going to 165. In fact, you’re probably going to 130/135 for a longer period of time. So the question is, is that sufficient? Is it comparable to the reduction we see at 160 or 165? So, my lab is looking at specifically validating some of those common cooking practices that we could find online, because the USDA does not have set guidelines for sous vide beef products or other raw meat products. And so, we’re looking to see if those common cooking parameters are going to be sufficient and also what happens if you use some kind of ingredient in the bag with the meat product that might be contaminated. So, we see spices being recalled sometimes for salmonella or E.coli contamination. And, so, what happens if you put a spice on there that was contaminated? Well, in that desiccated environment, remember we talked about the pathogens having some, you know, ability to survive in that, sometimes they develop thermal resistance with using the same survival techniques. And so, we wanted to see, does that impact the inactivation efficacy of the sous vide cooking, if perhaps the contamination came from the spice.

JH: Okay, great. Thank you. So, Jennifer, you work with both undergraduate and graduate students, and you engage with the community on food safety issues. But you also have a summer program called FOCUS that you run with fellow program directors Kristen Gibson, Jamie Baum, and Jill Rucker. And I understand this program is for students who aren’t even necessarily involved in food science. Tell me a little more about that.

JA: Yeah, so that is a USDA-funded program, and it’s called research and extension experiences for undergraduate students. And ours is specifically called the Future of Food Opportunities and Careers for Undergraduates. And so, what we’re doing is looking for a set of individuals – we have eight to nine fellows each summer – who come in from around the country. Primarily we look for students who might not be represented in the food science field, and we’re trying to expose these students to opportunities for careers in the food industry. So, we provide them with some research, industry, and extension experiences over the summer, and allow them to get first-hand and kind of frontline knowledge and exposure to what a career in food science would look like. Food science is an incredibly applied field. You have people involved in food science from a public health perspective, from a legal perspective, engineering, chemistry, biology – all of these different disciplines converge, and they just apply to food in a specific way. And so, there are a lot of people who will get a degree that they don’t realize could be applied in the food science field. And the great thing about food science is that you have pretty good job security, because everybody has to eat. And I don’t see that changing anytime, right? So, a lot of the students we had last summer were primarily excited about finding out about new career options because, with certain degrees, you might be limited in what you can find immediately after graduation. So that’s really our primary goal is, just, to expose people to food science when they might not otherwise know about some of these opportunities that have existed.

JH: Great! All right, Jennifer Acuff, thank you so much for joining us today!

JA: Thank you so much.

Matt McGowan: Short Talks from the Hill is now available wherever you get your podcasts. For more information and additional podcasts, visit arkansasresearch.uark.edu, the home of research and economic development news at the University of Arkansas. Music for Short Talks from the Hill was written and performed by local musician Ben Harris.