Jerry Shurson, animal science professor in the College of Food, Agricultural and Natural Resource Sciences at the University of Minnesota discusses the concept of upcycling and how food waste could be used in animal feed.
PODCAST: Upcycling’s role in sustainable animal feed production (29:29)
Ann Reus: Hello and welcome to the Feed Strategy podcast. I’m your host, Feed Strategy senior reporter Ann Reus.
Today I’m speaking with Jerry Shurson, animal science professor in the College of Food, Agricultural and Natural Resource Sciences at the University of Minnesota. He’s here to discuss the concept of upcycling and how food waste could be used in animal feed.
Hi, Jerry, welcome to the podcast.
Jerry Shurson: Hi, Ann. It’s great to join you today.
Reus: Can you explain the concept of upcycling for those who may be unfamiliar with it?
Shurson: Yes, it’s becoming a very popular term that I think maybe many of our listeners are hearing maybe more than once. And it’s really a pretty simple concept of recycling or reusing something in a way that results in a product that’s greater value than the original one that we started with. So we really think of it as sort of a value-added proposition of getting better use out of something that otherwise would be discarded.
Reus: And can you explain thermal processing and how it is used to create animal feed from food waste?
Shurson: Thermal processing is just a bit of a fancy way of saying heating or cooking. We often use scientific terms or more formal terms like thermal processing when we write scientific publications. But when you think about all the different types of byproducts that we use in animal feeds, many of those undergo various types of thermal processing or heating, including rendering processes for animal protein and fat byproducts. The spray drying process that’s used to produce animal plasma products are a couple of examples. We even use toasting of soy flakes during solvent extraction to produce soybean meal and rotary dryers to make distillers dried grains with solubles. So these are some common examples of the heating processes that are often used. And when we think about processing, or heating food waste, the process is fairly similar to those that we would use for rendered animal byproducts for example, where we might use temperatures between 250 to 275 degrees Fahrenheit, and high moisture over about a 30-minute to one-hour time period to destroy pathogens, bacteria and viruses that may be present in some of that material. So, thermal processing is a key component of being able to ensure feed safety from a microbiological point of view in many of the feed ingredients that we use, and also to dehydrate them.
Reus: What types of food waste can be used in animal feed and what are the regulations regarding this?
Shurson: Well, first of all, Ann, I want to be really clear, because I think there is a lot of confusion or maybe misconceptions about the concept of feeding food waste to animals, and specifically to pigs. And what we’re really talking about today is not the old fashioned, traditional, what I call informal, farm-scale practice of garbage feeding, as we used to call it, of table scraps to pigs. Upcycling of food waste into animal feeds now is really done at a industrial scale level where large-scale food processing and production facilities continue to capture many of the byproducts that I just mentioned a moment ago, that were obtained or are obtained from different human food manufacturing processes, whether it’s leftover inedible parts from slaughter plants that go into rendered animal byproducts, whether it’s soybean meal, for example, from oil extraction, or all these other kinds of examples.
But in the case of other types of food processing, we’re really talking about items that are “off spec” as we would call them, or they don’t meet certain quality standards to go into the wholesale and retail food supply chain. They might be inedible for some reason, maybe there’s a contamination issue, certainly not a food safety one but inevitable from a human attractiveness or perspective and they may also be unpalatable. Or, more of what I’m focusing on today are the components of the latter part of the food chain where we talked about pre-consumer waste sources or post-consumer food waste sources that are discarded, and then are upcycled into commercial feed ingredients for livestock.
And when you ask about, what are the regulations and what types of food ways can we be using an animal feeds, it really comes down to our current regulations dictate to some extent, what types of food waste can be fed and where they can be fed. And so briefly, the regulations that have been developed here in the United States came about a few decades ago, probably back in the late 1990s or, in the case of the Federal Swine Health Protection Act, that was put into place in the year 1980, so several decades ago. And the whole purpose of putting these regulations in place was that, back in in the early days, when no regulations effectively existed, there was some transmission or at least suspected linkages of transmission of foot-and-mouth disease, for example, through feeding animal-derived food waste to pigs, and even some concerns back in the days when mad cow disease that we officially call bovine spongiform encephalomalacia or BSE, was occurring. Those two major animal health problems really caused regulators in the legislature here in the U.S. to enact some regulations at the federal level. And the whole goal, of course, of the Federal Swine Health Protection Act is to protect human and animal health by making sure that the food scraps that we feed the pigs are free of any active bacteria, parasites and viruses that could cause disease if contaminated food waste is consumed by pigs.
And what this act really requires is that all meat and animal byproducts that are found in food waste, that we want to feed to pigs, are heated to boiling temperature, which I think as we know, is 212 degrees Fahrenheit, or 100 degrees Celsius for 30 minutes, by someone who holds a valid license or a permit. And this heating time and temperature is very similar. Actually, it’s not quite as high a temperature as what we would use for the rendering process to make meat and bone meal and blood meal and many of the other animal byproducts that we routinely use in animal and poultry diets. Now, this Federal Swine Health Protection Act does exclude certain food waste products, or certain food waste products are exempt. And they include bakery items, candy, eggs, domestic dairy products and interestingly, Atlantic ocean fish that are caught within 200 miles of the U.S. or Canadian continental border, or fish from inland waters in the United States that don’t flow into the Pacific Ocean. So, some of these types of food waste streams do not fall under this protection act that is in place.
And for facilities that are handling food waste that is intended to go into animal feeds, it must be stored in covered and leakproof containers until it’s ground and thermally processed. And, in the trucks that haul this type of material, there are certain approved disinfectants that must be used. But this Swine Health Protection Act does not apply to household food scraps being fed to pigs if the household food scraps are on the same premises or on the same, let’s say hobby farm or rural area where the food waste was generated. So you can feed your table scraps to your own pigs, but you can’t feed it to your neighbor’s pigs essentially is what that rule says.
And so, maybe to finish up this discussion about what we can feed and what we can’t feed, this Swine Health Protection Act sets the minimum federal standards but it doesn’t prevent individual states in the U.S. from imposing their own regulations that, in some cases, might be more strict or even prohibit the feeding of food waste to animals, whereas others have no regulations at all and everything in between. And just to put this into context, I chose a couple of examples: If you live in Alabama, for example, Alabama prohibits the feeding of all animal-derived and vegetable food waste to swine. So they are very restrictive in allowing food waste to be upcycled into animal feed. However, if you live in Alaska, for example, they don’t have any laws that regulate the feeding of food waste to animals. And if I put a state like the one I live in, in the state of Minnesota, feeding animal-derived and vegetable food waste to livestock and poultry is allowed, provided that it’s properly heat treated, and fed and processed by a licensed facility. In fact, in the state of Minnesota, the state regulations indicate that if you have food waste that’s derived only from frozen or canned food byproducts, they can actually be fed directly to livestock and poultry without any heat treating, as long as a facility has a permit indicating these are exempt materials. Another regulation in Minnesota would be that individuals and facilities need to obtain a license to transport food waste over public highways if it’s going to be fed to animals. But again, as I mentioned earlier, if you if you live in Minnesota, and you’re feeding household food waste to your own pigs, you can do so without heat treating and without a permit. So, here are three separate states with three very different kinds of regulations regarding the feeding of food waste.
And so, in addition to this variation among different states, we also at the federal level, have something called the Ruminant Feed Ban, which was put in place back in the days of the mad cow disease outbreak, or the BSE outbreak. And essentially what it says is that none of our feed manufacturing facilities are allowed to use mammalian protein and feeds for ruminant animals because of the concern about the transmission of prions, which are the disease-causing agents in nervous tissue of ruminant animals if they’re infected. So we have those kinds of restrictions, as far as prohibiting food waste. We also, I think, as many of our listeners know, all feed manufacturing facilities today must comply with the Food Safety Modernization Act preventative control rules that apply to food waste, and every other ingredient that are made, which include things like following good manufacturing practices, hazard analysis, and risk-based preventive controls. So, many people don’t realize this, but we do have a lot of regulations, even though they vary somewhat from state to state, that do control feed safety in upcycling food waste into animal feeds.
And maybe I’ll just make a few final comments on this question, Ann, and that is what we have to be aware of when we think about all the different food waste streams, and these would be pre-consumer, as well as post-consumer food waste streams. We want to find streams that don’t have a lot of contamination of things like paper and disposable styrofoam and plastic because those obviously cause problems with handling, they have no nutritional value and, in some cases, depending on what it is, it might even be a feed safety hazard. And, at least in the case of pigs and poultry, feeding fruit and vegetable waste probably isn’t the best choice – it can be done of course – but because fruits and vegetables don’t have a lot of energy, they’re higher in fiber, high in moisture, not much protein, they would be better suited for diverting into ruminant feeds compared to monogastric diets.
And I think maybe one of the big issues, and we can talk about this maybe a little bit later in the podcast today is, because of the risk of introducing foreign animal diseases into the U.S., especially African swine fever (ASF) virus, any incoming pork, in particular, or meat products in general, coming into the United States through airports from international travelers or cruise ships, we need to think about diverting these types of food waste sources, perhaps into composting facilities or ruminant feeding applications to avoid those types of materials getting into feed supply chains that may end up going to pigs because of the potential risk even though all of these are required to be heat processed, as well.
So maybe that hopefully provides a bit of an overview of the types of food waste we can feed. A lot of our work and research conducted here at the University of Minnesota over the last maybe seven or eight years, we’ve looked at the energy and amino acid digestibility and nutrient composition of food waste sources coming from county transfer stations, for example, from household source-separated organic waste streams that are common here in the Minneapolis-St. Paul metropolitan area, even supermarket waste and cafeteria waste coming from our university dining halls, fish waste and fruit and vegetable waste. And we’ve published some of this research in some journal papers that I’d be happy to share with our listeners if they have an interest in this.
- “What a Waste” — Can We Improve Sustainability of Food Animal Production Systems by Recycling Food Waste Streams into Animal Feed in an Era of Health, Climate, and Economic Crises?
- Leftovers for Livestock: A Legal Guide for Using Food Scraps as Animal Feed
- Energy, amino acid, and phosphorus digestibility and energy prediction of thermally processed food waste sources for swine
- Estimated energy and nutrient composition of different sources of food waste and their potential for use in sustainable swine feeding programs
- The Role of Agricultural Science and Technology in Climate 21 Project Implementation
But to make a long story short, I guess we were quite surprised, and maybe we shouldn’t have been, that all of these sources, including some of the contaminated plastic and paper that was in the food waste at the county transfer station, provided very high energy and protein values that we’re pretty convinced can be used to replace substantial amounts of corn and soybean meal in practical swine diets, as long as it’s ground and, of course, thermally processed. And maybe the only one of these different types of food waste streams that we evaluated, that being the fruit and vegetable waste, would have less value, but certainly could fit into a gestating sow diet, for example. So, we were pretty excited, and I’m pretty passionate about the opportunity to use this upcycling idea to not only provide new feed resources to the swine and livestock industry, but in doing so have a substantial impact on reducing the environmental footprint of food animal production.
Reus: How much food waste could be eliminated with a wider practice of upcycling?
Shurson: You know, in the U.S. alone, depending on what publication you want to read, food waste has been estimated to be about 30% to 40% of the entire food supply. In fact, a recent publication I was reading a couple of weeks ago indicated that annual food loss and waste in the U.S., and this is according to the Environmental Protection Agency, is the greatest in the U.S. compared to any other country in the world on both a total food waste and lost volume or amount and the amount on a per-person basis. And globally, it represents about 8% contributions to greenhouse gas emissions. So, it’s a huge, huge amount. The amount that’s recycled, or upcycled, currently, into animal feed is mostly coming from food manufacturing processes and grocery stores, as I’ve kind of alluded to earlier, but it only represents about 10% of the total surplus food that’s wasted.
So this to me indicates we have a tremendous opportunity to capture more of it if we could put in place adequate collection, transport, processing and distribution infrastructure that would allow us to efficiently process it and follow the current regulations, and also make sure that we’re diverting any higher-risk type of materials to other uses from a food security or a food safety point of view. And currently, World Wildlife Federation is actively involved in in the whole concept and education of food waste as well. And, and some of the estimates coming out of there, I think, are pretty realistic. And this organization has suggested that 14.7 million tons of food waste could be safely used as animal feed.
So I think, yeah, we have a long way to go. The U.S. made a commitment several years ago to halve, or cut in half, the amount of food waste occurring in the United States by the year 2030. We haven’t even come close to that. Not even close. And so, to me, a major effort needs to be put in place to upcycle all of this loss that’s having negative environmental impacts, could be used for productive purposes and, interestingly, I know a lot of our listeners that are involved in purchasing new types of novel feed ingredients may be aware of this, but if we have food waste streams that don’t fit into safe upcycling, going into animal feeds, we can divert some of those food waste sources as nutrient sources to produce insect meal or black soldier fly larvae, for example, and other insects which are becoming really popular, high-protein sustainable feed ingredients that we can use in poultry and aquaculture feeds in particular. So, upcycling of food waste doesn’t necessarily have to go directly into swine or other livestock, but it could be used to produce other types of high-value ingredients like insect meal, for example.
Reus: How are upcycled ingredients utilized in animal feed? Can they replace conventional ingredients or are they used alongside them?
Shurson: Well, it’s a really good question, Ann, and I made a few comments about this a few moments ago, but it really depends on the type of the food waste stream that we’re considering. Based on our research, if we use food waste blends from supermarkets, for example, that have some deli cheeses and meats, along with some bakery byproducts, and fruits and vegetables, kind of the whole mix of what you would find in a full-scale supermarket, or even cafeterias and restaurants, which have a nice blend of perhaps animal types of foods like meats and cheeses, along with fruits and vegetables and breads, and so on, those kinds of blends actually have equal, if not better, metabolizable energy value compared to corn and soybean meal diets. The amino acid profiles and digestibility are as good, if not better. So with a little bit of tweaking, so to speak, of using those types of food waste sources in swine diets, for example, by maybe simply adding some supplemental vitamins and trace minerals and maybe some other mineral and synthetic amino acid supplements, you’ve got a complete diet.
On the other hand, if we’re talking about more specific things like fish waste, for example, which has composition very similar to fishmeal that, I think many of us are pretty familiar with, that needs to be, of course, blended along with other energy sources like corn, or other types of grain byproducts and so on, and other mineral supplements to make the complete feed. So it really depends, I think, on the source of the food waste, what its energy value is and what the nutrient composition happens to be.
Reus: Now, you mentioned African swine fever virus a few minutes ago, and I know you’ve done some research on ASF and the virus’ survival in feed ingredients. I wanted to tie that together with the upcycling concept and ask you about the safety of feeding upcycled food waste to animals such as pigs when we know food waste can be a vector for ASF. So how can upcycled food waste be used safely in pigs and other animals and can you explain a little bit more what are the regulations around ASF and the practice of feeding food waste?
Shurson: Well, I think you’ve hit on the key point and maybe one of the major barriers, Ann, of adopting more aggressive implementation of upcycling food waste into swine diets in particular, and that is the risk or the perceived risk of African swine fever virus contamination or the introduction of foreign animal diseases. I think everyone here knows, that’s listening, perhaps that here in North America, we’re fortunate that we don’t have African swine fever virus. I hope we never get it, but you never know. And we’re doing everything that we can to keep it out of the United States, whether it’s through imported feed ingredients, or maybe more importantly, in my opinion, putting stricter border controls for incoming passengers that may be smuggling pork products in their luggage or food waste coming off of these airline flights and cruise ships and so on.
So, to answer your question, I think making sure that we’re preventing the introduction of pork meat, blood, casings used for sausages and other things coming from outside of the U.S. into the U.S., I think is critical, and we need to continue doing that. And we need to keep that out of the food waste recycling or upcycling process, because we don’t know, because we don’t measure, whether or not these products are contaminated with foreign animal disease viruses or not.
And I guess my second comment would be that, because we don’t have African swine fever virus in the U.S., there shouldn’t be any reason why, if we follow these Swine Health Protection Act guidelines of heating all types of food waste for 30 minutes at boiling temperature or more, following the Food Safety Modernization Act guidelines, which all feed manufacturers have to follow anyway, and certainly, we have the ruminant ban in place to feed rumen byproducts back to ruminants. So, following our existing regulations, I think, should be adequate, and using only licensed facilities that can produce food waste into swine feed, can go a long way to provide the level of biosafety or biosecurity necessary to do this, and at the same time, be able to prevent the transmission of African swine fever virus or other foreign animal diseases to pigs through upcycled food waste.
So, the simple answer, I guess, Ann, is that if we have high-risk material, that we’re concerned about, diverting it away from animal feeds all together by putting it into composting or biofuels production through anaerobic digesters, for example, would be one way to handle it, but there’s an awful lot of material that doesn’t fit into that category, that’s produced here domestically that really needs to be upcycled for more productive purposes.
Reus: Well, thank you, Jerry. This is a lot of great information on a really wide-ranging topic.
Shurson: You’re very welcome, Ann. I really enjoyed the opportunity to share some ideas with our audience today.
Reus: And I’d like to thank the listeners for tuning in. This is Ann Reus for Feed Strategy.