 Welcome everyone. My name is Julie Garden Robinson. I'll be your host for today's sixth field of fork webinar for the season. This is brought to you by North Dakota State University Extension. And if you missed any of the previous ones, they are all archived on the field of fork site along with several years of other archived webinars. In fact, this is the eighth year we've done the series and we're really glad you joined us today. The next slide shows our upcoming webinars. And we hope you join us for these as well. The next slide shows our webinar controls. Because of the large number of participants, we invite you to post your questions and comments in the chat box. So let's practice finding and using the chat box. And you can ignore the Q&A box. We're not going to use that today. So click to open the chat and then enter your city and state. So we know where you are. Very good from lots of different states. That's for great. It's great to see that. So you can continue doing that. The next slide provides an acknowledgement. As you work on typing in your city and state, I have a special request. This program is sponsored in part with grant funding from the USDA's Agricultural Marketing Service. And I will ask all of you who are here today to complete a very short online survey that will be emailed right after today's webinar. And as a thank you, I will be providing prizes for the lucky winners of the random drawings. And we've already sent out a lot of prizes. But be sure to include your complete address, including your city, state, and zip code so that we can send your gift to you to the right place. Well, we're ready to introduce our guest speaker. Byron Chavez is a food safety extension specialist at the University of Nebraska-Lincoln, where he provides training and technical assistance to food manufacturers in food safety, sanitation, and regulatory compliance. Byron is a native of Costa Rica, and he obtained his PhD in 2015 from Texas Tech University. We're really glad you're here today, Byron, and it's all yours. Thank you so much, Julie, for the invitation. And this is my second time in this seminar series. And I was looking at last year's presentation, and it was almost exactly a year ago that I gave my first presentation for this series. So thank you so much for having me again. Today we are going to talk a little bit about time temperature control for food safety. And what does it mean for food processors and entrepreneurs? Okay, so I will give you a really brief introduction of what is the purpose of temperature control. And then we're going to talk about different food products and how temperature controls are important for those food products based on the microbiological hazards that could potentially be present there, and then how do we use temperature to control microbial growth. So again, thanks for having me. We'll start by establishing here that the microbial profile of food products can be very complicated. And when we think about food, of course, we could think about fermented foods. We can think about foods that are spoiled, right, or we can think about foodworm pathogens. So all of these microbes could potentially exist together in a food matrix. So the microbiological profile of the food product will be determined by many, many different aspects. Some of those aspects are related to the physical chemical characteristics of the food product, and those are things like water activity and pH. And you may have heard about those things, right? Those are intrinsic characteristics of the food product. The water activity is an indirect measurement of how much available water we have in the food product for microbes to grow and produce different reactions. And of course, the pH is an indirect measurement of acidity. And we use those two factors, pH and water activity as control strategies in food. However, there are also extrinsic factors or external factors that influence the microbial profile of food product, food products. And today we're going to be talking specifically about temperature. However, this is not the only one. We can have relative humidity. We can have the amount of oxygen, for example, in a food packaging system will influence the microbial community and the microbial profile in those products. The other thing that it's important to realize at this moment is that microbes can be introduced at any point in the food supply from primary production to domestic handling. And just to give you an idea, most processed food products, things like packaged foods that we buy at the supermarket are safe, right? The microbial and chemical and physical safety of those products has been tested for a number of years. And so we have systems in place that will prevent different types of contamination. Interestingly, most of the foodborne outbreak cases that happen start in food service and in domestic settings, right? So food service would be things like restaurants, cafeterias, childcare facilities, elder care facilities, hospitals, things like that. And then of course, domestic handling is the things that we do at home. And so it is really important that we reinforce some of the behaviors that we use to protect foods. Now at this point, I also want to remind you or to give you this two definitions that are really important for what we're going to talk about. Hazard and risk. When we think about hazard, that will be the actual physical, chemical or biological agent that it's going to cause illness or injury in the consumer. So if we say microbiological hazards, that would be something like salmonella or pathogenic E. coli. If we say chemical hazards, that could be things like allergens or pesticide residues. And when we say physical hazards, that would be things like rocks, stones, wood, metal shavings, metal pieces, etc. Now a concept that it's highly related is risk. And that is the probability that that hazard will actually cause illness or injury in the consumer. And of course, estimating risk is not as easy as saying medium, high, low, right? We can use those qualitative measures to describe risk. But in general, when we estimate risk, we want to have a number. So it is very complicated. But I just want you to keep these two terms in mind. Now everything that we do in the food industry and everything that we do in food production really should be aimed at risk reduction strategies. So basically what this means is we want to minimize the probability that somebody will get sick by consuming the product that I make. Or I don't want, as a consumer, I don't want to get sick by consuming packaged foods or products that are sold in, you know, in a farmer's markets or anything like that. So we want to reduce the risk. We want to mitigate the risk. So then when it comes to microbial growth, as I mentioned, there are many factors that influence how microbes grow in food. However, temperature is one of the ones that we can definitely use for controlling some of that microbial growth. Each microbe has a minimum, an optimum, and a maximum growth temperature. And that is what you can see in the table, right? So in this table, we see that there are different groups of microorganisms and that there is a minimum, an optimum, and a maximum temperature. You can also see on the bottom left in the graph that microbes will grow up to a point and then they will die, right? So they will have a minimum temperature that it's the one that they use to grow. They will have an optimum, which is where the microbes will be in the highest quantity, and they will have a maximum after which they will stop multiplying and they can die, right? So those groups of microorganisms are classified in different ways. But the one that I really want you to pay attention to on the slide is the one in red in the red box. These are mesophilic bacteria or mesophiles, and those are the ones that can grow at room temperature. Those are the ones that feel perfectly comfortable growing at very moderate temperatures, right? So when we leave something out, when we leave food out, that it's not refrigerated, those are the microbes that can start proliferating very, very quickly. And so among the mesophiles, there's not only spoilage bacteria, but there's also pathogenic bacteria. And we need to be careful about leaving things out that need to be refrigerated or cooling things down with the right cooling rate, so that those mesophilic organisms don't start multiplying and either spoiling the product or potentially growing to a level where they will make somebody sick. So as I said, every microbe has a minimum, an optimum, and a maximum. And so the ones that I, you see a lot of colors on this slide, I didn't realize that it was going to be so colorful. But the ones that are in red, I want you to pay attention to those first. These ones are the ones that even though they are mesophilic, they prefer to grow at very moderate temperatures. They can also grow in refrigeration. And that poses a problem for food safety, of course, because in the food industry and in food production, in manufacturing, we rely on low temperature, a lot, to prevent microbial growth. But if you see those three that are in the red boxes, plus three in botulinum type E, Listeria monocytogenes and Eurasinia and Eurocolytica, those are microbes that can grow at very, very low temperatures, and that poses a problem for food safety. So we need to eliminate them in some other way. We need to apply other types of control, other types of controls. If they are present in refrigerated foods, they can grow, even though they will grow very, very slowly. However, they can grow, and so they present a problem. So I want you to remember those Clostridium botulinum, Listeria, and Eurasinia. Now on the other hand, we have things like Campylobacter, which is the dark blue box. And Campylobacter is very sensitive to temperature changes, so we can typically rely on temperature to control it, more than other microbes. And then the last one that I want to talk about on this slide, it's Staphylococcus aureus. And you guys can see that Staph aureus has two optimum temperatures, one for growth and one for toxin production. And toxin by Staph aureus is a very common thing that happens, and this leads to an intoxication, is when people get violently sick very soon after consumption of the toxin, typically within 30 minutes to 4 hours. And so we see Staph aureus toxin production in things like potato salad that has been temperature abused, those sorts of things. Also milk, fresh milk, that has not been pasteurized and hasn't been adequately refrigerated. So we continue to see the importance of temperature control to prevent foodworm illness. Now, like I said, most pathogenic bacteria grow at moderate temperatures, but some pathogens are capable of growing at refrigeration like the ones that I mentioned, Listeria, Clostridium botulinum type E, Angersenia, and Aurocolytica. And this of course presents a problem, because in the food industry we rely a lot on low temperatures such as refrigeration, cooling, chilling and freezing. On the other hand, of course, temperature can be high, temperature can be a thermal lethality step, right, and that is not the purpose of what we're going to talk about today. But we can of course, of course, pasteurize or can and retort, baking, right, those sorts of operations will use high temperature to kill microbes, and it's an excellent way of killing microorganisms. But going back to the point of refrigeration, of course, we'd rely on these things a lot in the food industry. Now you may have heard of this term, right, and this is a term or this is a zone, the temperature danger zone, it's a very traumatic name, but I love it, because it really is the temperature where microbes grow happily. Right, if we give microbes the right conditions and we give them time, including temperature conditions, adequate temperature conditions, those microbes are going to grow to a point where they will either cause illness in the consumer or produce enough toxin to cause illness in the consumer or will spoil the product. And of course, we don't want any of those things. The temperature danger zone is a temperature where microbes can grow very, very quickly. We typically refer to it as 40 to 140 degrees Fahrenheit, you will see sometimes in the literature and online that is 41 either or 40 to 140 is a safe, safe range of temperature for the temperature danger zone. And so when we temperature abuse a product, basically what that means is that we are keeping a food product that it's supposed to be refrigerated under non refrigerated conditions, or that we are keeping a food product that it's supposed to be hot. Then we're keeping it under conditions that are not hot enough to prevent microbial growth. Right, so in food service, for example, it is particularly important that we hold products that need to be cold at under 40 or 41 degrees and that we keep the ones that need to be hot above 140 degrees. The reason for that is to prevent, of course, rapid microbial multiplication, microbes can multiply extremely quickly given the right conditions. And so you guys see in the graph on the slide that there is a minimum internal temperature for safety, right, and you've probably seen that before where we have parameters, let's say for poultry 165 for egg dishes 160 things like that. Right, and so those things all become particularly risky foods. Most temperature in the refrigerators and domestic refrigerators that we use at around 40 degrees and then zero degrees Fahrenheit or negative 18 degrees Celsius is typically the lowest that we can get at with a domestic freezer. So those are important values to know. Now the purpose of today is to talk about time temperature control for safety foods, and we are going to start defining these things. Now these definitions come from the food code and the US food code, there's a new version that 2022 food code that was released in December of 2022. The food code is a model document that the US FDA, the Food and Drug Administration puts out every five years with the best science and recommendations that we currently have to prevent microbial growth, mostly applicable to food service, domestic food preparation, farmers markets, mobile units, such as food trucks and things like that. So we can apply the principles that are contained in the food code, then every state has a food code of them of their own. Right, so there is a Nebraska food code, for example, that it's modeled after the food code. Now, state food codes may not be updated as often as the federal food code, the federal food code it's updated every five years. And so sometimes there is a little bit of a delay or some lagging in the science that is reflected from the federal food code versus the state food code. So that is important to know. However, the regulations for your state will be based on your state's food code and not on the federal food code. Okay, so then going back to this definition, time temperature control for safety, those would be foods that require time temperature control to limit pathogenic growth, right, or pathogenic the growth of pathogenic microorganisms or toxin formation. And so maintaining these foods at the proper temperature reduces the probability of foodborne illness. And remember that I said at the beginning, everything that we do as food entrepreneurs or food processors, or anybody handling food, really what we want to do is to minimize the risk that that food is going to make somebody sick. And the way that we minimize the risk is by applying different interventions. Some of those interventions is temperature we don't want to temperature abuse a food product because that leads to rapid microbial growth. So this is a lot of text, but I will, I will break it down in a couple of slides. When we think about temperature control for safety foods, these are things like animal foods that it's either raw or he treated. It could also be a plant based food that it's he treated or consists of raw seed sprouts, cut melons, leafy greens, cut tomatoes. Typically things like garlic and oil mixtures, things that we have historically associated with high risk right and we'll see in a second why they represent a high risk. Now the other thing would be food products to which we don't add anything that could potentially limit microbial growth. When we are thinking about manufacturing foods in the food industry food preservatives are very common. But sometimes if we are thinking about a small company a small producer a food entrepreneur that it's developing a recipe for example, and wants to put that in the market. Sometimes we're not thinking about preservatives right sometimes we're thinking about an alternative to foods that are manufactured. Sometimes people may not be aware that there are preservatives out there that can that they can use to prevent microbial growth and to help maintain the quality of the food product. Now the other situation where a food will be a temperature control for safety is if it requires a product safety assessment based on the food code and I'll get to that just on this slide. Remember I said at the beginning, hopefully that pH and water activity are two intrinsic factors that are used to control microbial food, microbial growth in foods, right so they interact these are two factors that are so incredibly interactive with each other. So we have these tables that we can find the food code whether it's the model food code or your state's food code. And it basically says that if a food product has a water activity below 0.92 and has a pH value under 4.6, those food products are the safest. They tend to be microbiologically stable. They tend to be shelf stable meaning that we don't have to refrigerate them. But as we change those conditions, then we need to start making product safety assessments and a product safety assessment is when you go to your extension office for example if you go to Dr. Gordon Robinson and you ask, these are the conditions that I use to produce my food product. Is it safe? Are these conditions enough to prevent microbial growth and to make my product safe? Right so that is what a food safety product safety assessment means and I get a lot of those questions here in Nebraska where somebody is developing a recipe or somebody is developing a product and wants to put it in the market. But the question is, am I doing enough to prevent microbial contamination that can make somebody else sick? So we can have a couple of tables that you can find in the food code that will be related to this specific topic on how water activity and pH interact. Now the reason why I'm bringing these two tables up, it's because for anything that says PA that requires a product safety assessment, those products need to be refrigerated. The reason for that is because they don't have any other barriers, right? When we think about barriers for microbial growth, if you have a product that it's dehydrated, let's say beef jerky, right? If you have a product that has a very low water activity, microbes could potentially survive but they are not going to multiply. If you have a product that has high acidity and therefore it's very acid and has a pH below 4.6, then that pH is typically controlling for microbial growth. So think about fermented food product or a pickled product, anything that has been acidified. But for products that don't have any of those barriers, then we need to refrigerate. So then when in doubt, refrigerate the food product that you are developing until you know what are the physical chemical characteristics of that product. My first recommendation or the recommendation that I give everybody that it's starting with a business, it's always send samples to a lab, right? Send samples to a lab, send samples to your extension office, or at least they can help you find a lab where they will characterize the physical chemical characteristics of the product or determine the characteristics of the product in terms of pH and water activity, right? And once you start knowing your product a little better, you are the one that knows the formulation the best, you are the one that knows where are you sourcing the ingredients, right? But we need to make sure for safety purposes that you also know the water activity and that you also know the pH of that product. So for anything that has a high pH or a high water activity, when in doubt, always refrigerate that product. Now here are some examples of things that need to be refrigerated and the reason why. Now this is not a comprehensive list of microbes and I can tell you I am a microbiologist and I did research in microbial food safety and I could give you a much longer list of things but I don't want to scare you too much. I only want to scare you enough so that you really pay attention to refrigeration and other control measures. But we all know and we see these things and these names on the news. All the time we see outbreaks, we see recalls, we see issues in the food industry with things like listeria monocytogenes, salmonella, clostridium botulinum. We don't want those things. We know that those things have consequences for the producer, have consequences for the consumer, for the health system. People die, of course people die, particularly people that are in vulnerable populations such as children, the elderly, people that are in immunocompromised, pregnant women. There are consequences for foodborne illness. So why are these things temperature control for safety? Well, sprouts, for example, so most fresh fruits and vegetables and cut produce, fresh cut produce need to be refrigerated. This is also one of the reasons why if you go to your state's cottage food law list of things, it is a little restrictive, right? It is restrictive because we want to prevent people at home manipulating food and producing certain foods that are extremely high risk. Even if you wash your hands, even if you cooked it to the right temperature, there's always the possibility that food is going to make somebody sick. I know that cottage foods are becoming more and more lax and a little more relaxed, right? We see that in Nebraska. I think North Dakota is one of the states also where it has become very popular. And so we need to be aware of these microbes and the different control measures that we have. So let's take a look at raw seed sprouts, cut leafy greens. These are food products that can be potentially contaminated with pathogenic E. coli. You may have heard of Estek bacteria, Listeria monocytogenes, Salmonella. These are the things that we see all the time in recalls. And then you go to the supermarket and all the back salad shelves are empty, right? Because there's spinach that it's contaminated or romaine lettuce, right? So very easy things to contaminate. Now, when it comes to cut melons and mixtures of cut tomatoes, for example, this could also be contaminated with Listeria and Salmonella, so we don't want that. Anything that it's a cut fruit, whether it's strawberries or pineapple, melons, anything like that, could be contaminated with Listeria monocytogenes and you really shouldn't keep that food product, at least in transit, for example, if that's something that you are handling. It really shouldn't be in transit under refrigeration for more than four hours. So there are very strict guidelines that we have for handling those products because we know that they are high risk. Of course, if you have anything like a garlic and oil mixture, that is high risk for Listeria and botulinum because in that specific mixture, we tend to eliminate the oxygen, whether it's because you warm it up or because the oil in itself will prevent oxygen introduction into the product and so the risk of Listeria is high. Now, let's look at foods that are of animal origin. We know that most seafood, including cooked seafood and sushi, can be vehicles for Listeria monocytogenes, Salmonella, Shigella and Beavru. Very dangerous bacteria. We're not going to go into the details of any of these, but mortality rate, for example, for Listeria monocytogenes, is up to 33% depending on the outbreak. So basically that means that for every 10 people that get Listeria monocytogenes, three of those people are going to die, which is a lot of people. The mortality rate is really high. Let's see boiled or steamed cereal products such as rice. We always have the risk of bacillus cereus and neurotoxin. That toxin can be two types, one that will cause you to or make you vomit and the other one will make you poop your pants or both, right? So if you're lucky, you're going to get both of those at the same time. It is not likely that you're going to get both at the same time, but it could happen. And then of course we can have fresh milk and most milk products including some cheeses and they can be contaminated with a variety of different bacteria that you see on the slide, right? So these are the types of microbes that we need to keep in mind when we start developing products and thinking what are the conditions of my product and what are the microbes that could be associated with this product so that I can start developing control measures for that, right? Whether the product is going to be sold in retail at a convenience store at a farmer's market, whether you're going to sell it to your neighbors or put it online, we always need to be thinking about what are the things that I should be doing to minimize the risk of making somebody sick, right? You don't want to be liable for that. You don't want your product to be associated with making people sick. And then at the same time, it is very difficult to say what food products are going to make people sick and under what circumstances, right? People go to school for years and years to determine these things. So you come into this source of talks and webinars, it's really the first step, awareness, it's really the first step. So I'm really happy to see so many people here today. Now, I don't want to keep scaring you too much. Fortunately, it's after lunch. Sometimes when I give these talks right before lunch, I cannot see your faces, but sometimes I can see people's faces reacting to these microbes. And so let's think about meat and vegetable-filled cereal products, right? So including bakery products that are stuffed with meats. They can have a number of different bacteria, including salmonella, stapharius, and autotoxin. And of course, meat and poultry products are extremely high-risk commodities, right? Whether they're raw, whether they are raw or ready to eat. Ready to eat foods are not as stable or ready to eat meats are not as stable as we may think, right? So things like beef jerky or beef sticks can always make us sick, right? They could potentially make us sick depending on how they were produced. And so these are some of the reasons why we cannot make these sorts of products at home to sell as cottage food. And Adam, I'm not up today with the North Dakota Regulation or other states regulations, but we cannot make these sorts of products in Nebraska just yet. And the reason for that you see on the slides, there are so many microbes that are associated with these food products. Okay, so now that I've scared you, scared you a little bit with so many microbes, and the reasons why we do not handle those products at home, right? And why food service and in domestic operations we need to be so careful with cross-contamination, with cooling, with cooking. You know a little bit more of the context of the why. So the following operation should follow required temperatures and times according to the US FDA food code. Refrigerated storage, 41 or less, right? So it's something it's refrigerated, make it 41 or less, hot holding above 140, cooling. Cooling is particularly important, and most people don't realize that. Any food products that you make at home that you're going to sell, whatever you're going to sell it, needs to be adequately cooled down. When you cook a product, cooking it's only really half of the effort to kill microbes. You cook the food product. And then a lot of those microbes are going to die. But if you don't cool down the product adequately, then there are other microbes that could potentially grow. And so when we think about other microbes, those would be microbes that form spores. So spores of bacteria are very resistant to heat. So when you cook a food product, those spores may not die. And actually they will not die because they need extremely high temperatures and pressures to be inactivated. And so the way that we control for those spores to not make somebody sick is that we cool down the food product adequately. And so the general recommendation is that we want to go from 140 to 70 within two hours, right? Whether you put it in, whether it's at room temperature, however you are refrigerating or cooling down the product, and then going from 70 to 41 with an additional four hours. Those microbes will help us prevent microbial proliferation of microbes that may have not died in the cooking step. Those microbes are typically spore-forming bacteria. They form a resistant mechanism that it's called the spore. And microbes, including microbes such as clostridium botulinum, clostridium perfringens, and bacillus cereus. And all of those microbes have severe consequences for health. Okay. And so then the other recommendation is on the reheating step and we reheat food products to 165 degrees for 15 seconds. Okay, so we always want to measure. Remember when we measure temperature, we want to measure in the thickest portion and the thickest or in the more dense, the most dense, the densest area of the product. Okay. Time-temperature control for safety foods can be temperature abuse, of course, if they are in the temperature danger zone 41 to 140. This happens when foods are not cooked to the recommended minimum internal temperature, right? So there could be some surviving bacteria there. If they are not held at the proper temperature, and so if they are held at abusive temperatures, then the microbes will start proliferating. And if they are not cooled or reheated properly. Remember, if they are not cooled or reheated properly, some of those microbes that were not killed in the cooking step could potentially proliferate and cause illness. Now let's go to some examples of foods that are not temperature control for safety. And basically what this means is these are foods that are typically okay as a general rule. They can be okay being at room temperature as long as the package is intact, fully retorted and fully dried and salted seafood, right? So anything that we find in a can. So a can of tuna is microbiologically stable unless the can has been compromised, right? But those are foods that are in people's pantries for forever. Processed fruit and vegetable products, which is frozen, can, dried, fermented or acidified because they have all of those secondary barriers that we talked about earlier, such as the pH and the water activity barriers. But in that is why it's so important that we know the physical chemical characteristics of the products that we are making. Most baked goods, right? Most baked goods, I eat a lot of pastries because I have a big sweet tooth. And every time that I get a pastry, I always wonder about the feeling, right? If we have something that it's creamy, if we have something that is based on cream cheese, right? Those things start getting a little on the riskier side. If we have something that it's stuffed with a jelly or a jam or something like that, something that has a really low water activity that will prevent microbial growth, then those products are a little more stable, right? And so most baked goods, such as bread, are microbiologically stable. They will start developing some spoilage, mostly because of fungi. Salad dressings with a pH under four. And that would include also things like ketchup, hot sauce, right? If you have something that has been thermally treated and that has a pH of four or less, and those products tend to be very stable. Traditional sugars and syrups, right? Because the water activity is low, so microbes will not proliferate. Can milks and dried milk? Of course, this does not include powder infant formula, even though powder infant formula is a non-TCS food. Remember that powder infant formula, it's a particularly high risk commodity just because of the audience that it's going to consume, the powder infant formula, which is, of course, infants. Traditional hard cheeses, right? Anything that it's a hard cheese that has a relatively low water activity, especially if it's made with pasteurized milk, it's typically low risk, and hard boiled eggs with an intact shell. So many things that we can make that are low risk. But when in doubt, if you have a doubt about whether something is high risk or low risk from a microbiological perspective, you can always reach out to your local extension office. You can always reach out to us by email or give us a call. Tell us a little bit more about your product, right? Sometimes when I get calls from entrepreneurs and food processors, especially small and very small food operations, I ask a lot of questions, right? And we will ask a lot of questions because we need to know how is the product produced, what testing have you done on the product, all of those things so that we can better support you. So then when you call us, you know, it's always good that you have information that you can provide us. Now let's talk briefly about freezing. Freezing and microbial growth. We've been talking about temperature. So the example that I have on the slides here is freezing generally prevents growth of most bacterial pathogens but does not kill them, okay? And so when we freeze a food product, microbial growth will stop, right? We know that microbes are not actively proliferating in the freezer, but once we defrost that product or once we throw it out, then the microbes can continue to proliferate and they will, right? So that's why there are different throwing methods that are safe for different food products. Now we can do a slow or a quick freezing, right? The slow one, it's very good to eliminate a larger bacterial population, but it's not good on the quality of the food product. And the quick one, which is the one that we typically see for things like frozen peas and carrots or frozen cut fruit, that one is really good to maintain the quality of the product, and not eliminate as many bacterial cells from the surface as the slow freezing. In domestic refrigerators, let me, I'm sorry that I went back here, but in domestic refrigerators that only get to negative 18 degrees Celsius or zero degrees Fahrenheit, the only thing that happens is slow freezing, right? Those are not quick freezers. Now just to give you an example, let's say that you work in retail. You work in retail, not in retail, you work in food service, and you make sushi, right? Of course, if you are in a restaurant and you make sushi and you are a city fine rice, that is a high-risk commodity, right? A city fine rice requires a variance per the food code. So you need to have a permit from your local health department or the Department of Ag, I don't really know exactly how it might work in your specific states, but you need to have certain provisions. Now when it comes to freezing, freezing is a really good way to kill some microbes. However, those microbes are not bacteria. There's many different types of microbes, and bacteria is not a type of microbe that it's easily eliminated with freezing, but we can kill parasites. Anisakisimplex, which is the one that you see on the bottom right of your slide, is this worm that can be present in fish. But fish is after it's caught, it's rapidly refrigerated, and then it's placed in ice water to prevent proliferation of parasites, kill some of those parasites, and prevent bacteria from creating histamine, which is a chemical that can make or lead to an allergenic reaction in humans. Now there are guidelines from the federal government and other sources on how to eliminate parasites using freezing, right? So you can take a look at these things. Another example would be Trichinella in pork. So if you are in an area where you have a lot of wild boar or maybe swine that it's not conventionally fat, but they are outside eating whatever they can find, then it is a good idea that you look at these specific guidelines. Now I'm almost wrapping up and I want to leave enough time for questions. But the way that I want to wrap up this conversation is by talking about microbial growth versus microbial survival. We've talked a lot about refrigeration, why refrigeration is important. It is important because it can slow down microbial growth, even though there are some pathogens that can still grow in refrigeration, even if they do that very, very slowly. But microbes can survive under harsh conditions, even if they can grow. So sometimes we see outbreaks that are foodborne disease outbreaks that are associated with foods that we don't typically associate as risky foods. Think about ice cream, right? Listeria monocytogenes in ice cream or Listeria monocytogenes in frozen peas and carrots. Those are products where those microbes are not actually multiplying, but they got there from equipment or from an ingredient and they were able to survive. Microorganisms are very, very smart and they find ways to survive. Think about salmonella and peanut butter. Peanut butter has a relatively low water activity. It has a lot of fat. There's lots of conditions that would prevent microbes from growing in peanut butter, but we've had hundreds of illness cases of salmonella associated with the consumption of peanut butter. So even if you think that your product may be safe based on the characteristics, it's always good to ask based on the formulation and the physical chemical parameters of your product. When in doubt, always refrigerate your food product. Now, temperature control, therefore, it's only one of the ways of the strategies that we have to prevent microbial growth. The others that we typically use would be clean, right? We want to have clean, adequately clean and sanitized surfaces, including utensils. We want to separate so that we can prevent cross-contamination from one surface to the other. We want to cook to the right temperature or reheat to the right internal temperature to kill microbes, and we want to chill and reduce the temperature adequately so that we prevent surviving spores from growing. And so with that, I will close. I think we have plenty of time for questions and so I would be happy to take questions from the audience. Great. Well, I have been collecting the questions. And first of all, thank you very much. I think this was really helpful in knowing the why behind all the recommendations. So the first question is actually for me. Because I get asked this question periodically. What food or food product would you be extremely cautious to try due to potential food safety risk? You know, great question. And the way that I answer this all the time is we need to assume a level of risk, right? Most of us will not eat a... will not eat a burger that it's overcooked, right, a hamburger potty. So if we want to eat a medium rare or whatever, we need to assume a level of risk, right? So I don't eat certain... I don't eat sprouts. But sprouts, I don't need just because I don't like the flip. They also happen to be microbiologically risky. I eat... I love raw oysters. And here in the Midwest, we don't... I don't eat raw oysters here, but when I go to the coast, to the oceans, I do eat raw oysters. I do think, Julie, that the answer that I give people is awareness. You need to be aware that there is a risk associated with the consumption of those products. So if you do decide to eat those products and consume those products, then you need to be... you need to assume that level of risk. Good answer. Here are some questions from our participants. How long can packaged smoked venison sausage be refrigerated? Yeah. Well, without knowing anything else, right? Without knowing if you are adding any kind of preservatives and without knowing if you are packing that, let's say under vacuum or anything like that, I cannot really tell you the potential shelf life, right? Refrigerated meats have a varying shelf life. If the product is already cooked and it's adequately packaged, you can keep something in the fridge for a month or even more. And if you freeze it, the quality will be preserved for at least two years. But without knowing a little bit more of context, I would be hesitant to give you a number of days. We have a follow-up question to your comment about sprouts. What kind of sprouts do you mean? Do you mean Brussels sprouts or raw sprouts? Yeah, I do eat roasted Brussels sprouts. I love that. The sprouts that I'm talking about are the ones that... I don't know how to call them. What do you call, Julie, the long ones? Like bean sprouts? Kind of like bean sprouts that we typically get served in certain types of cuisines that are added, sometimes on the side. Those are the ones that I mean. Not everything that sprouts is that risky. The reason why sprouts are so risky is because there is a level of external contamination that is internalized into the seed. And then there's no way to eliminate it after it's internalized. So then after the seed sprouts, then that contamination remains internally. So there's very few things that we can do to eliminate contamination from sprouts. And we do want you to eat Brussels sprouts, everybody, because they're really good for you. Yes, they really are. The next question was about cutting boards. And I'm not sure if this is in your background as far as the type of oil that is safe for conditioning wood cutting boards. They mentioned specifically, is mineral oil safe? So I don't know the answer. I would say mineral oil. If it's food crate, one thing that you need to be aware is that the product needs to be food crate. And food crate means it can be used for food equipment, for surfaces. It doesn't mean that it's food safe, but it means that it has been approved to be, let's say, to be used on food contact surfaces. So I don't know exactly what type of oil. There are many different types of mineral oil, right? So I would be also cautious about that. But if you look at the, I believe it's the EPA, the Environmental Protection Agency, will have the list of approved food crate chemicals. And we have a little bit of a follow up to the smoked sausage. So here's a little bit of context. We like sausage in this area of the country. The packed smoked sausage was prepared by a small local processor. It is developing a milky liquid in the vacuum package, which has not been opened. And it was given to me five to six weeks ago. Yeah. I would think that that's, that that liquidy, if there's some kind of slime, it's typically a lactic acid bacteria that it's been developed is that I assume it's vacuum packed. Did they say if it's vacuum packed? Yeah. If it's vacuum packed, it's lactic acid bacteria. Does it present a risk for food safety? No. But if there are certain groups of microorganisms that are potentially growing there, then others such as clostridium botulinum or clostridium perfringes could also be growing. Right. So we need to be careful about, about consuming that product. I personally wouldn't consume it out of caution. Right. So, so that, that would be the, the only thing that I can say. Okay. And now a follow up on the mineral oil question. It's sold in the laxative area in stores. Yeah. There you go. Yeah. Well, you know, do you want to have cross-contamination to your product and then, and then having that, have that product? I don't, I don't really know. I do know that there are some newer versions of wood that are being used in the food industry, right? That are completely sealed and whatnot, but they continue to have cleanability issues. Right. So even though they are not as prone to microbial contamination as some, I don't know, wooden tables that we've used in the past, they are still not fully accepted in the food industry. Right. So the best thing it's always to use something like a polypropylene table that it's easy to clean. The issue with wood is wear and tear, right? So even if you have a surface that is intact at the beginning and you don't see it, those cracks and openings will accumulate moisture, whereas other materials do not accumulate moisture. The next question is about milk. Since we mentioned milk or you mentioned milk, is the UHT process for milk, the heat process that makes it shelf safe? Yeah. Great question. It is. So there are different types of pasteurizations for milk, right? The one that we typically do for the milk that goes bad quickly or relatively quickly, it's at lower temperatures. But if we use UHT treatment, but it's ultra high temperature, that's what UHT stands for. And it's typically only processed for a few seconds, something like two to five seconds, right in the pasteurizer process. And so that will make the milk much more stable, not only from a pathogen perspective, but from a spoilage perspective. The milk goes bad after some time because there are some microbes that survive typical pasteurization. Those are called thermoduric microorganisms. They can survive pasteurization, the one that we're used to. So if we use a higher temperature, we are eliminating more and more of those microbes. Now also remember that once you open the package, you can have UHT milk and refrigerate it, and nothing's going to happen. But once you open it, you have to refrigerate it. Great. Thank you. The next question is about, there's a couple of questions about frozen vegetables. And are they non-TCS foods or are they TCS foods? Should they be cooked before you use them, say in a salad? You know, that is an excellent question. I love that question. Those products are not TCS, right? So if you found it in the freezer at the supermarket, keep it in the freezer, right? That's the general rule. If you found it, whatever you found it at the supermarket, unless the label says, you know, do something different, those food products are not ready to eat. However, the federal definition of what is a ready-to-eat food product is not only that you can grab, it's not only that the label will say it's ready to eat, it's what the consumer will do with it. And we have seen in recent years, there's been a number of outbreaks that have happened, that have been associated with consumption of contaminated, let's say, peas and carrots, because people don't reheat those. They are intended to be reheat, but some people will eat them straight from the back or sprinkle them on top of a salad, and people have gotten sick, right? So are those products ready to eat? No, they're not, but the consumer is treating them as if they were ready to eat. They are not temperature-controlled for safety. They do need to be frozen, right? But I don't eat frozen peas and carrots out of a bag, but I do eat frozen cut fruit, right, that I just put in a smoothie, right? And so it's the exact same case. We need to be aware that those could be potentially contaminated. And just to follow up, someone else asked about using frozen cubed potatoes in a potato salad. So I guess the answer would be the same that... Mm-hmm. Yeah. The other thing with potatoes is that they are a good carrier for cholesterol and botulinum, right? Because they come straight from the soil that they had not been treated adequately. And depending on how they were backed, you could potentially create an environment for cholesterol and botulinum. Okay. Next question is about pre-cut melons. This is a great question. Are those really safe to buy? If you find them at the supermarket adequately on a tray, right, that has been refrigerated and you go to the store and you assume that this hasn't been temperature abuse, yes, they are safe to eat. They are always risky, right? And so for companies that produce fresh cut fruit, we work very closely with them, at least in Nebraska, in ensuring good manufacturing practices and having an environmental monitoring program for these three monocytogenes. Per regulation, for example, if you sell to school cafeterias under the USDA school launch program of the agricultural marketing service, you cannot have those products in transfer for more than four hours, right? So somebody that produces something in Omaha will give you, hopefully you guys know some Nebraska geography, but if you produce something in Omaha and you have to drive more than four hours to deliver the product, that product cannot go to a school cafeteria, for example. The next question is about maple syrup. What temperature should the clean bottles be heated to for storing maple syrup? 82 over 82 degrees Celsius. You would have to do the math for the Fahrenheit. Any containers should be, that is slightly below boiling water temperature, right? So above 82, which is what we would use to decontaminate utensils and bottles and things like that. Yeah. That's 180 Fahrenheit. I just looked it up. There you go. There you go. So just a little below boiling. Okay. Thank you. How long are eggs safe? Great question. If you buy them from the store and they are refrigerated, you can keep them even after expiration date, right? So after expiration date, what happens with the eggs is that the yolk, it's going to be really runny, right? Because it just chemical reactions and somatic reactions that happen. They can still be safe as long as you keep them refrigerated. If you have your own eggs of your own laying hands and you don't wash them, right? If you just keep them, then you can keep them outside. You can keep them outside as long as you don't temperature abuse them, right? If you don't keep them under the sun. But I would say for eggs that have not been washed and potentially waxed, I would give that maybe three weeks from a quality perspective. They're not going to last more than that. Okay. Thank you. Three questions left because we're almost done. They're testing you today. Is there more risk to grass fed or pastured meat as opposed to feed controlled meat? Any thoughts on that? Yeah. So from A, there are studies that have been done, right? Comparing sharing of E. coli 157 H7 and salmonella, or when we, we can swap the recto anal area of a cow, right? And collect, that's the way that we collect poop samples from cows. I did that a lot of my PhD. So I can, I can tell you stories, but there's really not a lot of difference between, between them. There are super spreading events that happen, regardless of whether the animals are pastured or grain fed, right? There are events, there are geographical characteristics, climatological characteristics, management characteristics and practices that will affect how much the animals will be contaminated. Now the one difference to that is when we do pork, right? And I mentioned trichinella for animals, the risk of trichinosis in swine that have been grain fed and that are kept inside is significantly lower than for something like wild boar or swine that it's just roaming around. All right. So you have two questions left. If you make beef jerky or beef sticks using commercial packaged spices and cure, how do you find a shelf life for the product under refrigeration? Yeah, well those products are, are shelf stable, right? And that's why you walk into a convenience store and you can just grab them at the counter, right? So if you make those beef sticks that have a, that have been cured, right? So they have been treated, they have chemicals that will prevent the outgrowth of clostridium botulinum. Then, and then you cook the product and the water activity is low enough to prevent microbial growth. They really shouldn't be refrigerated. If you add refrigeration as a, as another control, I don't think that that product will be under the same category, the USDA or the State Department of Act would see it as a different category. If you need to add refrigeration, right? So the whole purpose of products like that, it's that they are going to be shelf stable. I don't exactly remember the question, Julie. Sorry. That was close enough. Okay. We have one question left and then we'll end our webinar for today. And it's about apple cider. Okay. And is ultraviolet treatment adequate for making apple cider? Or what do you suggest? Yeah. Great question. So apple cider, apple juices need to be treated to reduce different pathogens. Pathogenic E. coli, Listeria monocytogen is salmonella and a parasite called cryptosporidium parfum. So whatever treatment you use, whether it's a heat treatment, whether it's reverse osmosis, whether it's UV treatment, you need to prove that you are eliminating five locks of those microbes and five locks basically mean 99.999% of those microbes in the product. So regardless of the method that you use, and yes, UV light coupled with ultrafiltration certainly works to eliminate pathogens in apple cider. But you need to be able to prove that you're eliminating those five locks to sell it, whether you are under FDA inspection or under state inspection, they will typically ask you to prove that. Well, very good. Well, we are at the end of our hour and I just want to thank you for joining us. I think you gave us a lot of things to think about and you really gave us that background information on why we say what we do in the world of food science and safety. So I appreciate that. And I appreciate everyone for joining us the different weeks and we hope you join us again next week. So thanks everybody. And especially thank you Byron. Thank you for having me. Thanks everybody.