In this episode of the Pet Nutrition Show, hosts Amanda Falconer and Dr. Anna Sutton dive into processing and the impact that has on nutrition and quality. The results may surprise you!
They also discuss the importance of variety in pet food, rotating between protein sources and meal formats.
They explore the variety of protein sources, like animal by-product meals, insect protein, and plant-based proteins, noting their nutritional profiles and the role they play in a pet's diet.
Toward the end, Dr. Anna shares a fun 'food hack' for making a refreshing pet treat using melons and bananas.
Here are the headlines:
- Different processing methods for pet food include lightly cooked, fresh cooked, slow cooked (retorted), air dried, freeze dried, and extruded (kibble).
- Lightly cooked pet food is cooked in a similar way to casseroles and commonly frozen.
- Fresh cooked pet food is usually found in rolls and cooked in a steam oven. -
- Slow cooked pet food is retorted, which is a sterilization process that allows the product to be stored without refrigeration. This is typically used for pouches.
- Air dried pet food is dehydrated at a low temperature for a long period of time. It is highly digestible and retains nutrients well.
- Freeze dried pet food goes through temperature cycles to remove water, resulting in a low moisture content. It is considered to have a high nutrient retention, similar to raw food.
- Extruded pet food, such as kibble, is made by blending, cooking, and shaping the product through a machine. It allows for the use of various ingredients and can include raw meat.
- Proteins in pet food can come from animal byproduct meals (meat and bone meal, lamb meal, poultry meal), meats (frames, heart, lungs), plant-based proteins (soybean texturized vegetable protein), and insect-based proteins (black soldier fly larvae).
- Animal byproduct meals, although not commonly consumed by humans, are still valuable sources of nutrients in pet food.
- Meat-based proteins have a favorable amino acid profile for dogs and cats, but plant-based proteins can be blended to provide a more complete profile.
- Insect-based proteins, like black soldier fly larvae meal, have a similar amino acid profile to animal proteins. They are a good alternative and contain high levels of naturally occurring fats.
- Insects are becoming increasingly popular in pet food, especially in fresh formats, due to their availability and sustainability.
- Variety is important in a pet's diet, including different protein sources and formats, to provide a range of nutrients and support a functional gut microbiome.
- When examining food labels, look for information about the inclusion of vitamin and mineral premixes, which are widely used and highly bioavailable.
- Transitioning between diets can be done gradually, especially for pets not accustomed to frequent changes. Food hacks, like introducing small changes or incorporating different formats, can help acclimatize pets to new diets.
- The food hack mentioned in the script is making doggy popsicle treats by blending melon and banana, filling popsicle trays, and freezing them. These treats should be given in moderation due to their sugar content.
Here are a couple of clips:
Have a listen to the show, but if you’re more of a reader, here is the transcript:
[00:00:00] ANNA: This is the Pet Nutrition Show with Amanda and Dr. Anna. Welcome to the Pet Nutrition Show. I'm Dr. Anna Sutton. And I'm
[00:00:09] AMANDA: Amanda Falconer and in the past few episodes, we've interviewed experts from around the world. But this week, it's time for me to find out. Flip things around, I'm actually interviewing Anna, who for the last few years has been a small animal nutritionist, formulating diets for companies in Australia and internationally.
[00:00:28] AMANDA: But before that, she spent almost 20 years in one of the world's largest ingredient companies. Now, why is that important? Well, there is not much she doesn't know about processing, and that's part of what we'll talk about today. But first, it's time for a quick question.
[00:00:45] ANNA: Pet Q& A, where we answer what you're wondering about food, moods, and
[00:00:51] AMANDA: poos.
[00:00:52] AMANDA: Anna, last week I asked you about whether one type of offal is better than another. Today, I want to ask about something that I [00:01:00] saw in a blog post during the week and its title was, a raw diet isn't complete without offal. Is that
[00:01:06] ANNA: true? Yeah, that's an interesting post and yeah, technically it is true because in a true raw diet, these often aren't supplemented with vitamins and minerals.
[00:01:17] ANNA: From other sources. So, so like we do in a formulated kibble, for example, or wet pet food. So all the vitamins and minerals have to come from the food sources. So when you do formulate a raw diet, one of the challenges you have is getting the right vitamin A and actually vitamin D levels. So to get your vitamin A, you usually include.
[00:01:39] ANNA: Some offals and particularly liver, which is extremely rich in vitamin A. So yeah, absolutely on board with that one for a raw diet. But let me
[00:01:48] AMANDA: put an alternative to you. So if I'm feeding, for instance, a muscle meat and something like a bestie balancing supplement, which doesn't have offal, that still makes it complete and balanced, right?
[00:01:59] ANNA: [00:02:00] Yeah, it does. And, uh, balances usually contain other ingredients that supply that vitamin A. So yes, in that case, now you could still add a little bit of offal, but if you're using a balancer like a Bestia or any of the other commercial balancers out there, you probably want to limit your offal inclusion to probably around 5 percent or less of the total diet.
[00:02:25] AMANDA: We hear a lot about the benefits of raw and fresh feeding these days, but that doesn't necessarily mean that pet food produced in other ways is bad. So, can you take us through what's common? Aside from raw, there's lightly cooked, slow cooked, air dried, freeze dried, retorted, extruded. So, let's look at them.
[00:02:47] AMANDA: What impact does the processing have on the quality of the food? Let's start with
[00:02:51] ANNA: lightly cooked. Oh gosh. So lightly cooked. So yes, we have an absolute smogger's board available for your pets. And, and lightly cooked usually [00:03:00] refers to the types of products that are actually cooked in a similar way to way we make casseroles.
[00:03:05] ANNA: They're usually in. Large, small batches in large pans. They're cooked for a fairly short period of time, just enough to cook the ingredients. And then they're usually vac packed and frozen. So that was lightly cooked. Moving on from there, we have fresh cooked. So these are the things like the rolls that you see, you know, in, in pet stock or what have you.
[00:03:27] ANNA: So these are a little bit different in the fridge. Yeah. So these are high meats, usually high meat inclusion again, and various starches for binding and all the rest of it. And the way they're cooked is they're cooked in their packaging and they're cooked in. I can't what's like a big sauna really, or steam room is probably a better idea.
[00:03:47] ANNA: It's a steam oven that they're cooked in and they cooked around 74 to about 80 degrees Celsius. So that's a, a low temperature, quite a long process, a few hours, and that's there [00:04:00] to retain all the ingredients and nutrients through the processing.
[00:04:04] AMANDA: So how does that compare then from a nutrient point of view, just before we go on, how does that compare to lightly cooked, for instance?
[00:04:12] ANNA: Well, they're probably fairly similar. I would say you may well have slightly higher nutrient retention in a, in a steam cooked due to the temperature being lower, but they would be very similar because the time of the cook for lightly cooked is usually a bit shorter and often with lightly cooked, the heat sensitive ingredients are added later.
[00:04:35] ANNA: Not always, but often. And what about slow cooked? So slow cooked is a little bit different. So slow cooked in pet food speak, generally means it's retorted. And what a retort is, it's basically a massive pressure cooker. And so essentially what retort does is it takes the temperature of a product all the way up [00:05:00] to above 121 and we do that to achieve a sterilization step.
[00:05:05] ANNA: And when we sterilize a product, it means we can then store it at ambient without having, so in our, in our houses without having to put it in the fridge, the whole process takes around four hours. It's not at 121 degrees for four hours, but the whole process is around four odd hours. So that's probably why people call it slow cooked, but that's actually what it is.
[00:05:25] ANNA: It's used, that's terms usually used for pouches. I've noticed the same process really is canning in many ways. At least the cook part is.
[00:05:34] AMANDA: And how does it compare to Lightly cooked and fresh cooked from a nutrient retention
[00:05:39] ANNA: perspective. Yeah, you get much higher losses in retort. So you do account for those in your formulations.
[00:05:45] ANNA: So particularly of the water soluble vitamins, you, you do have to, to watch those. So it's definitely a high temperature, high challenge process in that regard. Again, when retaught formula is adequately [00:06:00] formulated for nutritional completeness or adequacy, they're absolutely a valid diet for pets. On to air dried.
[00:06:09] ANNA: Air dried is a little bit like the beef jerky you get, you know, for us. So. Essentially, this is a drying or dehydration process, usually around 60 odd degrees for a long period of time. So usually, you know, it could go on for eight, 12 hours. Most pet food companies have to put a step at the beginning just to bring the temperatures right up to kill all the nasties before they dehydrate.
[00:06:36] ANNA: But the hallmark is it's a slow process. And, and the key benefits of air dried are around. The lower temperatures tends not to damage the proteins as much. So it's quite, it's a highly digestible format, still get nutrient losses, but again, you account for those in your formulations and the way you balance your diets.
[00:06:57] ANNA: Now,
[00:06:57] AMANDA: I remember when Ziwi Peak, for instance, [00:07:00] first came onto the market and it was air dried versus. Let's say dehydrated, so what's the difference between those two or, or is that just marketing?
[00:07:09] ANNA: It's kind of marketing speak. Okay, fine. I'm afraid you're dehydrating. You're removing, in both processes, you're removing the water.
[00:07:16] ANNA: Right. You could argue that there are different types of dehydrators. Some have circulating air, some work under a vacuum. or partial vacuums, but really you're still dehydrating, right? You're taking the water out. And that's how you're achieving stability. Now, what about
[00:07:33] AMANDA: freeze dried? Because it's certainly one of the fastest growing food categories in pet food.
[00:07:38] ANNA: Freeze dries is an interesting one and it's quite complex. We'll probably have to get a freeze dry expert in to properly explain it. But essentially you're going through, through temperature cycles in freeze drying. And what you're doing is. Causing the ice to form in the material, and then you're putting it on the vacuum.
[00:07:58] ANNA: And usually at that [00:08:00] point, you're introducing heat and what that does, it makes all those ice crystals turn to water vapor and come out of the product. I'll probably not describe that in perfect technical terms, but, but that's essentially what it is. So this goes through multiple, multiple cycles. So freeze drying doesn't.
[00:08:17] ANNA: Unlike air drying, you're not lifting the product up to 60 or 80 degrees for any period of time. So it's definitely it's, it's, it's closer to raw in that regard by reducing the moisture all the way down to usually it's around 4%. That's how you're maintaining then the stability and the safety of the product in terms of mole growth and bacteria growth.
[00:08:38] ANNA: So it is a very popular format. And in terms of nutrient retention, it's kind of the gold standard really next to raw.
[00:08:45] AMANDA: Right. And so now we come to the one that's been around forever, extruded, which is a technical term for basically how kibble is made or dry
[00:08:54] ANNA: pet food. Good old extruded pet food. The extrusion bit is basically [00:09:00] the bit where we blend, cook, and we shape the product through quite a big machine again.
[00:09:07] ANNA: And then from there it goes into a dryer, a big dryer. Then it goes into a coater where we add our fats and, and our, our flavors or our palatine systems. So extruded. Pet food is a high temperature process because we're getting up to sterilization temperatures in an extruder often, or we should, sorry, we always are, 121 odd.
[00:09:30] ANNA: When you're making extruded pet food, you have the ability to use lots of different types of ingredients. So we can use starches, we can use plants. a lot of plant based ingredients. We can use, and we use meat meals, protein meals and so forth. So we can use a far more, more by products or co products if you like, than we could in say, an air dried product or even a fresh cooked product.
[00:09:56] ANNA: And you can do lots of different things with with [00:10:00] extruded diets. You can even include high percentages of raw meat. So extruded format is a very useful one and one of the key benefits is you can make a truckload at once.
[00:10:12] AMANDA: So you also mentioned when we were talking about some of the other formats that, for instance, freeze dried didn't impact or affect the quality of the protein quite so much.
[00:10:25] AMANDA: So what is happening to protein, for instance, in the extrusion process?
[00:10:30] ANNA: So at high temperatures, proteins denature, which means they change their shape, which means that we can't use them or our dogs and cats can't use them quite as well as they could have done perhaps in a more native form. So there's a few caveats here in a raw meat.
[00:10:49] ANNA: you know, it's great to keep it as unprocessed as possible. And that, uh, means all of it's, or most of it's, bioavailable and digestible for the animal. [00:11:00] In extrusion, we're using meat meals and protein meals, and these are less bioavailable, less digestible than a raw meat, but still very useful. But the temperatures again do impact the digestibility.
[00:11:14] ANNA: So At kibble we're probably running around 80 odd percent, uh, well actually probably closer to about 87 percent digestibility. A raw food you may get up to about 90 something, 92, 93. Thereabouts.
[00:11:30] AMANDA: So, I guess, just to recap, in terms of a sort of hierarchy of nutrient preservation and quality, could you say that it goes raw, freeze?
[00:11:46] AMANDA: Air, fresh cooked, lightly cooked, retort, kibble?
[00:11:51] ANNA: Yeah, pretty much. I'd almost put kibble before retort in some regards. Okay. But, but again, you know, with formulation, we know about these [00:12:00] losses and so we account for them. So, end products. With a complete and balanced label are, are exactly that. Now, when
[00:12:08] AMANDA: it comes to ingredients, could you give us an overview of the different protein sources commonly used in dog food, such as by product meals, which we talked about last week with Laura Ward, meat, plant based proteins, and even insect based proteins?
[00:12:24] ANNA: Yeah, sure. Look, we'll start with the animal by product meals. These have evolved. Over the years, they're not rubbish as people think, think they are, they're produced in standardized ways to generate a very useful byproduct, which we need for pet food. So typical animal byproducts include meat and bone meal, which is usually beef.
[00:12:46] ANNA: We have lamb meal, which is often termed ovine meal. poultry meal and feather meal. Now they all differ in the nutrient profile, their amino acid profile, their fatty acid [00:13:00] profile, and also their mineral composition. So when we formulate with these, we often use a mixture of meals to achieve. You know, what we want in terms of their digestibility, these meals vary in digestibility, and it does depend on their composition.
[00:13:16] ANNA: And it depends also how they're, they're rendered. And that's a whole new topic of conversation, really. In terms of meats going into things like fresh pet food and cans and what have you, these fresh meats, these are typically parts of the animal that you and I might not eat. So typically frames, for example, chicken frames, which still have a heap of meat on them.
[00:13:40] ANNA: Hearts and lungs and organs are typical meats going into, to wet pet food and also into things like air dried and freeze dried often unless particularly otherwise stated. These often go into lightly cooked as well. Although lightly cooked will often have a full muscle meat as well. [00:14:00]
[00:14:00] AMANDA: So, before you get into plant based, I just want to cover off something.
[00:14:03] AMANDA: I think there's this growing narrative that if I wouldn't eat it, as a human being, then I shouldn't feed it to you, my furry friend. So, some of the things that you're, you've just described are things that We are not eating as humans. So does that mean that if we're not eating them, they're kind of like, uh, they're a bad thing for the dog, this lower quality kind of thing that we're feeding and, and, and we shouldn't do that?
[00:14:29] ANNA: Yeah, look, that's a great point. If I look at animal protein meals, well, You know, in their current form, no, you and I probably wouldn't chow down into them, but they're still a really valuable source of nutrients, especially if we know how to utilize them. Now, if we produce that protein source by a different method in a food grade environment, let's say we break down those, those by products are not going into.
[00:14:55] ANNA: our prime steaks or whatever in the food grade side with [00:15:00] enzymes and we create a slurry, we dry it, we'll get a protein powder. And we had quite happily chow into that in a protein shake or a beef burger as a part of a meat extender. I think there is the discussion of what can go to pet and what can go to us.
[00:15:14] ANNA: And there's some crossover between them in terms of how good they are for our pets. They're certainly valuable ones. And if we process them slightly differently, they'll be valuable for us too. Same with hearts, lungs, liver. So many parts of the world, they're delicacies and they go to the food, human food chain, and this is what's actually driving the price in particular of wet pet food up because the availability of those raw materials for pets is decreasing.
[00:15:42] ANNA: So, you know, they're essentially. human food grade, if you like, in that they're often harvested from the fruit, from a food grade stream and are in all intents and purposes food grade. So again,
[00:15:56] AMANDA: then coming to another piece of dominant narrative or narrative [00:16:00] that's growing, and that is that, you know, high meat protein or meat protein based diets are kind of the top of the pops.
[00:16:09] AMANDA: How does a meat based protein compare to a plant based protein in terms of giving a dog or cat what
[00:16:17] ANNA: it needs? So meat based proteins have a favorable amino acid profile in terms of what the dog or cat requires. But they vary between different meats, slightly, and you see much bigger variability in the actual meals because of the ash composition.
[00:16:34] ANNA: In terms of plant based proteins though, plant based proteins have many of the amino acids That a dog or a cat requires, but what we sometimes need to do is Laura said the other week was we sometimes have to blend them to get a more complete profile because plants differ slightly. So one example is that, uh, methionine is typically a little bit lower in a plant based protein compared [00:17:00] to a chicken, for example, sometimes lysine is a bit lower, but we can incorporate other sources to compensate for that.
[00:17:08] ANNA: So, plant based proteins certainly have a role and they've been used in pet food for a long time. You know, soybean texturized vegetable protein has been in canned food for forever and a day. We just not really noticed it before. And how
[00:17:23] AMANDA: does soy protein, for instance, compare in this amino acid profile to a meat or bone meal,
[00:17:30] ANNA: for example?
[00:17:30] ANNA: Yeah, so a meat and bone meal, a beef meal, which is typically very high in bone, its methionine notch is fairly low compared to other. animal protein meal sources. So in that regard, soy is actually pretty close. It's actually a little bit better, would you believe? Which is why soybean meal is used in a lot of feed based diets, actually.
[00:17:50] ANNA: Out of all the vegetable type meals, certainly in the feed industry, soy is a bit like the gold standard. Now consumers may not feel that [00:18:00] way.
[00:18:01] AMANDA: No. Okay. And we hear a lot about, um, other alternative proteins in the pet food space. So in terms of digestibility and nutritional value, how does insect protein stack up against more traditional sources like beef or
[00:18:16] ANNA: chicken?
[00:18:16] ANNA: Yeah. So insect came on the scene probably 2016, 17, we started seeing a bit of insect meal around. Insect is a broad term. It covers many species of. Insects, probably the most well researched I would say is black soldier fly. Although I did note the other day that mealworms have actually just been approved in the U S for pet food consumption.
[00:18:39] ANNA: So insects are a step between plants and, uh, animals. I would say that they're closer in their amino acid profile to animal proteins, uh, particularly fish actually, then a plant protein. They tend to be a little bit lower in [00:19:00] methionine. So often we have to balance with another protein or we need to use much more to get the required total methionine levels, but there are certainly a really good option.
[00:19:10] ANNA: Now the interesting thing with these insect proteins is, is they contain high levels actually of naturally occurring fats. And particularly in black soldier fly larvae, that fatty acid profile is quite favorable. So it includes most of the fats that we want to put into a pet food, or if the exception of the.
[00:19:31] ANNA: Long chain Omega 3s, EPA and DHA. So, so insects are a great alternative and they're really growing in their use. There's a couple of things that's limiting their use in pet food. So first of all, in terms of a protein meal, so dried rendered insect, the cost is still quite a bit higher than say a poultry meal or similar.
[00:19:52] ANNA: So that's why we're not, we're seeing quite slow adoption. However, on the fresh side, I think [00:20:00] this is where insects going to come into its own because the pricing on fresh or, or, uh, insects is fairly similar to some of these meats that we're utilizing in wet pet food. And so I think as the pressure on our supply chain for things like hearts in particulars and livers and what have you, increases due to human demand, I think we're going to see insect playing more and more of a part in, in wet pet
[00:20:31] AMANDA: food.
[00:20:31] AMANDA: So what do pets think about insects? Do they like them? And I know insects is a broad term, so let's just take black soldier fly. larvae meal for a second, uh, how palatable is it to a dog or a cat? Actually, there've
[00:20:43] ANNA: been quite a few studies looking exactly at this and the general conclusion is they're just as palatable as anything else.
[00:20:51] ANNA: You have to remember, Amanda, when we make a diet, we don't just use one ingredient. It's how we incorporate that ingredient, if you like, into the matrix. And [00:21:00] we often use palatants or flavor systems and different coating fats and what have you to, to enhance palatability or taste. So I would say. If we just had insect versus chicken and you had nothing else, well, probably my bet would be that the dog or cat would probably go towards the chicken as a more familiar taste.
[00:21:22] ANNA: But in the context of a whole diet, it's very effective.
[00:21:26] AMANDA: And so we've. Talked about high protein last week. So I want to just skip to if I'm a consumer, how do I make informed choices about my dog or my cat's diet? What should I be assessing when I look at different food options? And actually, before you answer that, we asked Laura last week, what do you look for in a food label?
[00:21:47] AMANDA: So let me ask you, I'm looking at a pack of food. What do I, what are the. Highlights that I need to look at in the food label to work out whether this is a good food or a bad food.
[00:21:57] ANNA: Yeah, they are. And, and the reason we [00:22:00] have to add vitamin minerals to most processed pet food is because we get losses through, through processing.
[00:22:07] ANNA: So, you know, whilst our ingredients do provide nutrients, unless you're utilizing a form such as raw or freeze dried, most of the time formulators will use a vitamin and mineral supplement and this sometimes will include the addition of amino acids to top up balances or adjust ratios for depending on what the purpose of that diet is.
[00:22:29] AMANDA: And so if I see vitamin and mineral premix on a label, am I thinking to myself, Oh, shitty synthetics, or are they actually quite good?
[00:22:40] ANNA: No, they're, they're all highly bioavailable. There's a lot of competition in the industry around bioavailability and efficacy. They're widely used. They've been used for many years.
[00:22:51] ANNA: They're well studied. So, in most complete and balanced formulations, they are an essential part.
[00:22:58] AMANDA: So finally, I mean [00:23:00] we did talk last week with Laura about the importance of, you know, rotating different proteins in the diet. So that, I guess, gives rise to the question, is there one right diet? for your dog or cat?
[00:23:12] AMANDA: And if so,
[00:23:12] ANNA: what is it? No, look, I, I don't think there is one right diet. I tend to agree with Laura in that I think variety is important. I think rotating between different proteins and different formats is important because every different pet food format you give to your dog will have a different impact.
[00:23:32] ANNA: on their physiology. It has to by, by definition. So introducing a variety of formats keeps life interesting for them. It minimizes the chance of nutritional insufficiencies and redundancies in some regards, and it allows the animal to have exposure to a broad variety of, uh, ingredients and nutrients, and that generally is [00:24:00] thought to support.
[00:24:01] ANNA: a more functional gut microbiome. So variety I think is spice of life.
[00:24:07] AMANDA: Thanks so much for that, Anna. You know, as a lay person, I think I'd sum up everything that I heard you and Laura say as this, mix it up. Have a diet that has different protein sources and different formats. And if you do that, it's likely to be super interesting for the dog or cat and healthy for their gut too.
[00:24:27] AMANDA: That does raise a question, doesn't it, about the instructions that we so commonly see to transition pets from one diet to another slowly, doesn't it?
[00:24:36] ANNA: Yeah, it does. It's quite confusing really for a typical pet owner because we're always told, oh, don't change your diet ever, ever, ever. But the reality is variety is good.
[00:24:47] ANNA: Now, if a cat or dog's not used to transitioning between lots of different diets regularly, then you do have to take it a bit slowly and give their guts a bit of time to adjust. Usually it doesn't take that [00:25:00] long. The actual, the changes within the gut microbiome actually occur. really actually a big chunk of them within the first 48 hours.
[00:25:07] ANNA: But for dogs that have been fed, or cats for that matter, a specific diet for a very, very, very, very long time, then they need some more time to adjust. And that's why incorporating, if you like, some of these food hacks helps acclimatise that dog or cat to changes.
[00:25:24] AMANDA: Which is a natural segue into this week's food hack.
[00:25:28] ANNA: It's time for Home Food Hacks with Dr Anna. Ah yes, this week's food hack. It's been pretty hot here. My dogs do like a cold snack when it gets hot. So what I did this week is I had some melon and banana left over. So what I did is I blended the melon and banana in my trusty blender. And then I filled these, you know, the little popsicle trays that you can get in the supermarket, the [00:26:00] ones that you make kids popsicles with.
[00:26:01] ANNA: What I did is I filled that up with my blend. I sprayed a little bit of oil into the popsicle holder before I filled it up and popped it in the freezer. And a few hours later I had my doggy Popsicle treats. Now I only give them one a day of these because they're quite high in sugar and I don't wanna overload them.
[00:26:21] ANNA: But my dogs absolutely love them and it's perfectly safe for humans too. So, you know, go for your life. The Pet Nutrition Show is proudly presented by planet, a pet food, bringing dogs, a flexitarian diet that's good for them and the planet.
