So welcome to the, the next, section of, training and pet food. My name's David Southey. I'm an animal nutritionist, been in the industry for about 33 years now.

And I'm gonna take you through, dry pet food production. So we'll look at some of the, the science behind it, obviously the production processes, and also the, the safety that's involved, with each process. So the first thing I'd like to say really is that as pet food producers, we've got quite a number of challenges.

We kind of sit between human nutrition and human foods and animal nutrition. So there's an expectation that our pet foods are, are going to be similar in terms of quality and look to human foods, but yet we're still governed by animal feed legislation. And also we're trying to make, obviously affordable pet foods.

We're in the business of trying to encourage pet ownership, so affordability of the food is important. So as we go through the presentation, we look at the different production processes, we've always got a mind, on all of these aspects that we have to target when we're making pet food. So they have to be very palatable, nutritionally complete.

Obviously they have to be safe. But we've also got very long shelf lives on a lot of our pet foods and that's why really dry pet foods lend themselves so well, to, to our dogs and cats' nutrition. And above all, they must be consistent.

That's one of our, our key, points really as we go through this, you'll see that consistency is king. a pet owner can only really assess the quality of the food by its visual appearance and maybe it's aroma. So consistency from bag to bag, and every mouthful needs to be as close as possible.

So we're gonna go through some of the what I call the traditional formats of dry pet foods. These are primarily what we call extrusion. So this is the dry kibble or dry biscuit production process.

This makes up the majority of pet food around the world really, so we'll spend a bit of time going through that and I'll try and explain how we pay a lot of attention to detail in terms of the digestibility and the the safety, the sanitation of the food as well. And then we'll look at, a few other formats like, baking, which is a very traditional format, pelleting, which is having a bit of a resurgence at the moment. But also we'll touch on one or two of the new technologies that we're seeing in the industry.

The pet food industry is very, very good at incorporating new technologies and adapting them to pet food. So you'll see that, you know, even though some of these technologies are way outside of, of food, we've kind of adapted them. We've used obviously the pet food friendly ingredients to produce quite novel, foods because we're always looking to innovate.

Customers are always looking for something new, something that's going to attract the dog, but also attract the owner, and that's obviously, key for our production processes. So we'll look at things like freeze drying, injection moulding towards the end. So we'll kick off with what we call extrusion, expansion, dry kibble production.

It's got many names, but essentially it's the same process. It's a process that we adopted in the pet food industry, back in the 1950s. It was originally designed for, cooking carbohydrates and cereals, and also for denaturing the anti-nutritional factors that you find in some pulses, in particular things like soya.

We then adopted it into the industry. We started to add some extra ingredients like meats and fats and different things to produce a nutritionally complete food, and really it evolved rapidly in the 1980s and 19990s to similar sort of production processes that we see today. So a dry kibble or dry biscuit is typically between 7 and 9% moisture content.

It, even though it's dry biscuit, it still contains some moisture. And they're very strict controls on that moisture content because when we start to get above 9%, there is a risk of mould development. So, that's a very sort of strict, KPI for us.

As we know, you can make a variety of shapes and colours using this technology, and that's one of the great attractions. As I say, we're trying to, sort of encourage the owners as well as the, the pets themselves with the varieties and colours and shapes and flavours that we have. Mostly they're nutritionally complete diets, and that's one of the big advantages of this process is that we can add all the nutrients that a dog or cat needs on a daily basis into the recipe, and very easily incorporated into a kibble.

They, as I said at the beginning, really, the technology was designed to cook carbohydrates, so there must be some carbohydrate in the production, in the recipe for the production to actually work. So even though we may want a very low carbohydrate content or even a zero carbohydrate content, it makes the product, this production process, very, very difficult. So you'll find that all recipes will contain a certain amount of carbohydrate, and obviously most of them are meat-based.

The 6 stages to the production process. The first two are where the cooking is actually done, so we call it preconditioning and extrusion. So this is, this, makes up about 90% of the actual cooking process.

The kibbles then dried to produce a crunchy texture. We then coat it with all of the flavours and attractants that that we need for the the cats and dogs to be to be palatable for them, and then finally we cool it down. So I'll take you through those in a second.

In terms of trends, what we're seeing really in the industry is over the last, I'd say 1015 years in particular, we've seen an increase in the amount of fresh and frozen meat and fish that's added into these recipes. Now, this technology was never really designed, to incorporate these sort of ingredients, but as technology has advanced and we've learned more and more about the process, we're now able to add quite high levels of fresh ingredients into the, into the recipe, which has its benefits in terms of digestibility and palatability. We're also seeing an increase in the number of non-cereal carbohydrates used.

So things like, potatoes, sweet potato, tapioca, millet, there's a whole range of, of different carbohydrates now, because there is this perception that, we're seeing an increase in the number of, intolerances to some of the cereals, particularly in dogs. And also, certainly over the last sort of 5 or 10 years, we've seen quite a dramatic increase in the number of plant-based vegetarian, vegan recipes and alternatives to meat, things like insects and, laboratory grown meat as well, is coming into the industry. So again, there's there's, there's not a particular trend, I would say, not one single trend, but there's a certain amount of new sort of avenues that we're going down at the moment.

So if you take a look at the, the flow of the production process, every factory is pretty much the same in terms of its flow. Obviously size varies dramatically, but what you'll see here is from the left hand side, you'll see that the, these are are bulk silos. These are the, these contain ingredients that are included in the recipe in high percentages.

So they're things like cereals, rice, maybe corn, and the dried meat meals, perhaps pork, chicken, beef, that kind of thing. That will all be mixed together and it will pass through a grinder or a hammer mill. Now this reduces the particle size to something that's very, very fine, typically about 1 to 1.2 millimetres in size.

That's really important in terms of, well, many things really, but in terms of the cook, how easily we can cook these ingredients, but also the consistency of the finished kibble. So once we have this powder containing the, the bulk ingredients, the minor ingredients are added to it either by hand or automatically, so these will be ingredients like perhaps yeast or egg powder, and the vitamins and minerals as well. So they'll be added in with the bulk ingredients, that will all then be conveyed through to the actual cooking process that I mentioned earlier, so this is, if you like, the extrusion process on the right.

So we've got 2 steps, as I mentioned in the cooking process. We've got the preconditioning and the extrusion. Then that's the kibbles are then passed through to the dryer.

Through To the coating system, to add the flavours on the outside and the fat, and then finally, into a cooler before it's passed through to to packaging. So it's a very simple process. You find factories are either linear like this, so they're horizontal, which is typical for a UK factory.

On the continent, you'll find some very tall factories because this is all a vertical process where the ingredients start at the top and the finished products at the bottom. So what are we trying to do with this process? Well, the key thing, as I mentioned earlier, is that we're cooking carbohydrate, we're cooking the starch.

Pets, monogastrics, just like ourselves, can't digest raw starch, so it has to be cooked. And that process is called gelatinization in the, in the case of extrusion. So what we're trying to do, we're taking all these various carbohydrates, as I mentioned, we've got a a huge variety of carbohydrates that we use now.

And we're taking these starch molecules and we're adding heat and moisture, causing these starch molecules to swell. And then finally, at the very end, we're causing them to rupture. So the rupturing of the starch molecules will produce a texture, as you can see in the, in the top photograph, similar to sort of honeycomb really.

And this tells us that the kibble is fully gelatinized or the starch is fully gelatinized and hence it's going to be fully digestible for the cat or the dog. This is really key, and it's something we keep an eye on through the production process and you can, you can look yourselves. If you actually break open a kibble, and have a look inside the kibble, you should see this honeycomb texture.

If you don't see it, the chances are it hasn't been extruded, correctly, and hence won't be as digestible for the dog and cat. And as I mentioned earlier, consistency is really key, in this process. It's quite an art form, it's very difficult to actually get this consistency from batch to batch and throughout the production process, and so we, we do have very skilled technicians that run the machine.

With the advances of technology, a lot of it is now done by computer, so it is easier to get this consistency, but we're dealing with natural ingredients, so there will be natural variation. But I think you'll agree that if an owner. Opened a bag of food one day and it was similar to the, the kibbles on the left hand side and then the next day it was similar to the ones on the right that we would start to get some enquiries and some complaints.

So consistency in terms of size, shape, colour, texture, aroma is, is obviously a key target for us. So this is the, the cooking equipment. This is the extruder and the preconditioner.

So the preconditioner is on top. It's a bit like making bread, if you like. So the preconditioner is effectively making the dough, if you like.

So it's taking the dry ingredients, adding the liquids, and mixing those very efficiently, before it is passed down into the barrel at the bottom, which is the actual extruder. So this is doing the majority of the cook. This machine is, it's about 4 metres tall, about 8 metres long.

It's about 5 or 6 million pounds if you, if you're looking to buy one. And it'll produce a 12 kg bag of, of dry kibble in about 3.5 to 4 seconds.

So it's very quick, very efficient, and hence allows us to make economical dog foods and cat foods. So if you take a look inside the, the equipment, the, this is the pre-conditioner, so this is the part if you like, that's kind of making the dough. It's like a very wet dough, almost like a slurry.

If you look inside, there are either 1 or 2 sets of spinning, spinning blades. These are rapidly mixing all those dry ingredients, and as they pass through the barrel, we're adding into that the liquids. So, water, generally.

Fresh meat or fresh fish if it's added to the recipe. And then finally, fat. Fats and oils will always go in at the end before the material exits the, the preconditioner.

And we're injecting steam from underneath. So we're trying to get to a temperature of roughly 85 °C, because we know at that temperature, it's starting to cause the starch molecules to swell. But also, it's sanitising the material, so there's no risk of any microbes actually living in that as it exits the the preconditioner.

So it takes about 2 minutes to pass through the preconditioner. And then it drops down into the extruder or the expander. So this is what really does the the bulk of the cooking and also forms the kibble.

And all this really is, is a long barrel made up of sections typically, and there's a screw, one or two screws that actually run down the centre of this extruder. Now as you can see from this diagram, as the material passes from left to right, as it exits the extruder, the flights in the screw become tighter and tighter. And what this does is it increases pressure, increases friction, and hence increases the temperature.

So towards the end of this barrel, we're getting to towards 120 130 °C for a very short time, literally seconds. But it's this process that actually causes the, the gelatinization. Then the ingredients come out the end of the extruder and we've got a set of spinning knives on the end which will chop the kibbles into the lengths that we need and obviously this the shape of the holes at the end of the extruder will determine the the shape of the kibble.

So from this, as it pops out of the the end of the extruder, it's a bit like popcorn if you like, you get this expansion. So that's what forms the crunchy texture and expands the kibble. So we've now got a kibble that's roughly the right size and shape, but it still contains around 30-35% water.

Obviously, we can't pack it like that, so we have to reduce the water content down to the, the target sort of 8%. So we'll then pass it through a dryer, and there are many types, and typically all we're doing is we're blowing hot air through the kibble bed to, evaporate out some of the moisture that's in there. So approximately 25% water will be removed in this process.

It's also running at over 100 °C, so again, we're keeping those kibbles, sanitised. There's no risk of microbial growth in there at all. And typically it will take about 40 minutes to pass through the dryer.

The next step then, so we've got a a very warm kibble, it's the right size, right shape, right colour, it now has a crunchy texture. Now we need to coat it. This is where most of the flavour and most of the fat er content is added.

So Many different types of of coating systems, either a batch coter or a continuous coatter, but essentially what we're doing is we're spraying the oils, fats, and the palletants, these strong flavours onto the outside of the kibble, and some of that will be absorbed into the kibble as well. Typically the palatins are meat-based, but they can be vegetable based as well, and they, they contain some of the highly flavoured parts of the, the animal, so for example, chicken livers or pork livers, that sort of thing. So now we've got a kibble, right size, right shape, right colour, texture, and it's got the, the flavours and the aroma of the finished food, but it's still warm.

So the final step is to cool it down. We take it down to roughly plus or -5 °C from ambient. So not a cold kibble.

We don't want to pack cold kibbles and then put them into a warm environment. We're basically trying to, reduce the risk of condensation in the bag. And that process takes around 20 to 40 minutes to bring it down to towards ambient.

So the whole process from start to finish, it's roughly between 60 and 90 minutes from the very start to the very finish, before it goes off to packing. So that's the process, the extrusion process for, I would say the majority of dry, pet foods all around the world. Now we'll take a quick look at baked pet foods, which is probably the 2nd largest dry pet food around the world, and is still considered the original pet food.

You can trace, pet foods back to the 1860s, so over 150 years ago. We were adding meat into cereals, forming a biscuit and baking it, and that really was the first, if you like, commercial pet foods that were produced. So it goes way, way back and hasn't particularly changed, very much in that time.

Traditionally they've always been, complimentary foods, so you need to add something to them, typically meat, if you all remember the, the pedigree chum and mixer sort of days, but quite often they, they're also snacks and treats, because you can make different novel shapes and things, in this process. Generally cereal based, and again, trends are away from cereals towards gluten-free, grain-free, recipes for the same reason that, we mentioned with extrusion. And more and more they're nutritionally complete recipes, so you can feed them as the only food for your, your pet.

The production process is, is probably what you, you'd imagine really. It's very similar to a domestic, baking process. So, we're taking the dry ingredients, we're mixing them together, we're forming a dough by adding liquids, so fats, water, fresh meat, if it's added, and then we're forming a sheet, and that sheet then is either cut into shapes or is baked just as a sheet and then crumbled at the end.

Big difference is whether it's a batch process. So whether we put all the kibbles or sorry, all the biscuits onto trays and then pass them into, an oven, a static oven, or whether it's a continuous process. So it's a travelling oven whereby the biscuits passed down through a long dryer, can be several metres long, and then at the end, the biscuits are formed.

So it has some advantages in terms of it, it looks very appetising, it looks, quite humanised. Obviously, cookies are made in exactly the same way, but also we can do things like, bake, animal parts, things like fish skin, for example, which are popular treats, and they're made in, in a very similar way. Another very traditional production method which seems to be having a bit of a resurgence at the moment is pressed pellets.

Now I use the term cold pressed because I know some of them are termed cold pressed, . Certainly the process is, is cooler. We don't use the same temperatures that you would do in extrusion and baking, but not all of them are are actually cold as such.

Very conventional process, used obviously in agriculture, a lot of, farm animal feeds are made in this way. They can be complete or complementary, so it has that advantage. And unlike an extruded kibble, where the kibble is actually held together by expansion, if you remember that sort of popcorn effect, holding the kibble together, a pellet is compressed.

So it's squeezed together quite often with a binder to help it stick together because they're quite friable, they, they're quite fragile, and. You'll find them in limited shapes. There's not a lot we can do, not like an extruder in terms of variety of shapes and, and colours as well.

What is true is that because the temperature of the production process is significantly lower than extrusion and baking, we have to pre-cook anything that needs cooking, basically. So, we mentioned earlier that monogastrics, of course, can't digest raw carbohydrate fully. So if the recipe contains carbohydrate, it must be pre-cooked before it is put into the, the press.

Also, because of those low temperatures, if you're adding any raw meats into the recipe, we have to cook the or pre-cook those raw meats because again, the pelleting process won't sanitise those meats, so it won't hit the the kill step that we need to make them safe. Certainly, it's, it's having a bit of a resurgence, I think because it's, it's variety. People like to see something different and certainly, over the last few years has a different appearance to things like dry kibble.

So one of the newer technologies that the pet food industry has adopted and adapted is freeze drying, originally designed for astronauts as a very low weight food that they could take into space. We've adopted it into the pet food industry and you'll probably see a number of particularly snacks and treats that are in this format now. It is, it has some attraction because it will retain a lot of the colour and the flavour and aroma of the starting ingredients, so you will retain a lot of the, as you can see here, the vegetable colours, and, a lot of the aroma from the meat as well in the process.

The challenge with it really from from our point of view is that it's a very expensive process. The equipment is expensive to produce it, but also the time to produce the food is much, much longer than extrusion or baking. So it's typically a 24 hour process, and, and you probably won't make more than about, about half a tonne, 500 kg of product in that time.

The process is basically freezing the ingredients together or individually freezing the ingredients. They're then passed into this vacuum chamber where because of the vacuum, the water actually evaporates at a much lower temperature. And so, like I say, you retain a lot of the colour and the aroma, and then it goes through a drying process to get rid of the extra moisture that's developed before it's packaged.

Similar to the, the pelleting process, there's no kill step. We're not adding high temperatures into the process, it's actually the reverse. So anything that needs sanitising, before it has to be pre-cooked, and the same with the, the carbohydrates, they must be pre-cooked before they go into this process.

We're seeing an increase of these freeze dried kibbles being added, into traditional extruded kibble. Again, a bit of variety, maybe a little bit of extra palatability in the food, but what is important and we pay particular attention to is any moisture migration because these freeze dried kibbles are so dry, they act a bit like sponges and they will absorb moisture from other kibbles. And once they increase in moisture, there's a risk then of microbial growth.

So again, we pay particular attention in these mixed, products that there's no migration by keeping the moisture levels similar. Another very traditional format, in the dry sector is raw hide. Been around for a long, long time.

I'm sure everybody knows and, and can recognise raw hide made from skins, typically of, of beef, predominantly made in the US, China, and Latin America and can be either natural or bleached. It's, it's attractive because it is a long lasting chew. It will occupy a dog for a long time and we can manipulate it into all sorts of shapes, .

So it's been around for a long time, and more recently, there have been different developments of adding other ingredients, things like wrapping meat around it or turning it into a bone shape. So there's been some development, but it's still a very traditional process, but still a significant part of, of the industry. Now, injection moulding is, is another really interesting one where the pet food industry has seen something, in another industry.

The, this was came from the plastics and the metal industries where things like light fittings and doorknobs were made, using this technology. And basically, we adapted it. We started adding edible ingredients into the process, and we were able to make some long lasting treats.

So you may be familiar with things like the, the dental brush here. And all sorts of novel shapes that are, a very hard, quite long-lasting chews, but also because they, they have a lot of contact with the teeth, they're quite useful as a vehicle for dental, hygiene ingredients. The process is, is the same really as the plastics industry, so what we're doing is taking edible ingredients, starches, sometimes meats, but typically vegetable-based ingredients, mixing them together, forming little beadlets which are then injected into this mould.

We then subject the mould to high temperatures and pressures, which causes it to become molten. And then as the, the molten beadlets actually, solidify and they're cooled down, they obviously take the, the form of the mould. So that mould can be anything.

And in fact, the very early injection moulded treats were the shape of doorknobs and and light fittings because that's the mould we had originally. And obviously now we have all all sorts of novel shapes and and sizes. It's then ejected and packaged, it has a very long shelf life because it's a very dry product and very, very solid, very durable.

So in summary, dried pet foods represent the majority of commercial pet foods around the world. You'll find in, in most countries of the world, they're, they're the leading, in terms of volume, certainly, the leading pet product. The UK is a little bit different actually.

We, we still have a very, high volume of wet pet foods, produced in the UK and fed in the UK, but most countries of the world, it certainly will be dry and particularly dry kibble that is the number one. They've been around for a long, long time. They, as I mentioned, they were the original pet foods, if you like, going back over 160 years with the baked, biscuit.

And recent technologies have allowed us to make something that's a little bit more attractive, as I mentioned, you know, we're, we're trying to, if you like, attract the owner as well as the pet, to provide something that's, that's novel and attractive for everyone. We take particular care to make sure that the digestibility, and the nutritional value is optimal, but of course also safe. So we pay attention to the moisture content of these foods and also that kill step that I mentioned that we're hitting the temperatures that mean that the food is going to be safe, not just for the, the pet, but also obviously the owner that's going to come into contact potentially with the food.

And we continue to look at new technologies. We're always trying to find something that's different, that's going to attract owners. As I say, we're in the, in the industry of trying to, encourage pet ownership.

So we're always trying to come up with something novel that's going to keep everyone entertained, and obviously, safe and nutritional at the same time. So thank you very much for your attention. I hope that was useful, and, yeah, I believe we're, we're having a, a session, a question session later in the year if you do have any questions.

Many thanks.