In this concluding programme, Julia Bradbury revisits her highlights from the series and discovers which animal part is used to produce our bestselling books.
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From the clothes we wear to the cars we drive,
from what we use to look good to what we use to relax...
-..our lives are full of products,
and our products are full of animals.
In the past few years, I've learned a lot about how the meat we eat
reaches our plates. But I've always wondered what happens
to the bits of the animal that we don't eat.
It turns out these leftover parts are made into things we use every day...
That's a symbolic noise for, like, leather.
..as well as some things you couldn't even imagine.
Oh, my God!
My face is on fire!
I've never, ever smelled anything like that.
'To find out how, I'm going on extraordinary journey
'to see these raw animal parts transformed into shiny new products.
'And I'm going to be joined by the people who use them to see what they make of it.'
-The sheep need to get slaughtered.
-Will we be in the room?
Oh, my God!
Mine had a testicle on it!
Oh, don't film me being sick!
'We'll be going behind the doors of unknown companies and into hidden worlds...'
That is such a weird vision! Just skin hanging there.
This is when we see what's inside the chest.
I don't think that's going to go in there.
'..and discovering what makes these animal leftovers indispensable.'
-I can't even look at it!
-What am I doing here with these?
Could knowing that so many of our favourite items
contain animals change the way we feel about them forever?
We are a nation of meat lovers. Every year in the UK,
we munch our way through tens of millions of cows,
sheep and pigs, and half a million tons of fish and seafood.
But our use for animals doesn't stop at the dinner table.
'Over the course of this series, I've been amazed to discover
'the ways bits of animal we don't eat can be turned into products we can't do without.'
I mean, that's just strange, isn't it?
'In this programme, I'll revisit some of the most shocking and surprising uses I've found.'
-Oh, my God! It's a fish!
'It turns out that hidden animals lurk everywhere,
'from our bathroom cabinets and bedside tables
'to our laundrettes and pubs.'
But despite the fact that we come skin-to-skin with these products
almost every day, most of us have little idea
about where they're from or what's in them.
'Including this group of lads from Manchester,
'who I took to a local slaughterhouse
'to find out how a car becomes a leather car seat.'
-Here we are.
-Here we go.
Friends Calvin, Curtis and Jordan like to look good
when they're out on the town. For them, a high-end motor
with a quality interior is an essential part of the image.
I want a leather interior.
It's got to be tan. It can't be cream or black.
You know that one that's not red and it's not cream? Like in between.
It's just that noise - that's a symbolic noise for, like, leather.
But had they ever considered where their sumptuous interior started its life?
Nobody thinks about that kind of thing.
They just want to see that leather in the car. It's a statement,
and it is quite comfy, actually.
No-one thinks where anything comes from at all.
It's on a shelf, so as far as you're concerned,
if you buy summat from Tesco, it's from Tesco.
It was made at Tesco.
And how did they feel about what was to come?
Anyone who sees something die or killed,
you're going to have some type of emotional reaction.
I don't believe anyone can stand there
and blatantly say, "I'm not bothered by that."
'With that in mind, I took the boys to meet John Mettrick
'at his family-run butchery business in the Peak District.'
'The Mettricks operate what's known as a best-practice abattoir,
'which means that animal welfare is a top priority.'
Welcome to our small abattoir in the Derbyshire hills.
This is Carlos here, the vet. He's looking at the animals at the moment,
to make sure they're fit and healthy for slaughter.
I don't want to get too close.
These animals are in an unfamiliar environment.
We won't bolt them with strange faces,
because it's very important to keep them calm.
What do you think, looking at the animals now, lads?
They don't look too happy. They look like they know what's...
Do you think of car-seat covers when you look at them?
When you see a cow, you don't think of the process.
You don't think of a potential car seat.
No. You think, "Oh, that could be a couch at DFS,
or be in a BMW." You just think it's a cow.
-What's next, John?
-We need to go and get kitted up
-to see the next part of the process, so if you'd like to follow me...
'We made our way to the lairage, where the cows are stunned.'
OK? Now, this here is the captive bolt gun,
which is used for stunning cattle. It doesn't shoot a bullet.
It shoots a piece of metal out - a bolt - into the animal's head.
And the bolt penetrates the skull and renders the animal brain-dead.
All its sensations are gone. Everything's gone.
It's effectively out.
You think you could do it?
-Shoot the cow in the head?
You'd get affected emotionally after you'd done it.
'We followed John to the slaughter hall, where the life of each cow is ended.'
Being on this side, knowing that a cow, in about two minutes or so,
is going to drop out at my feet, brain-dead, is a bit...worrying.
My heart is going sick.
That was it.
I just don't like it.
So now he's going to lift the animal up at an angle,
and he'll push it along this gantry here, right,
over the top of the bleed area.
Nah, nah, nah. This is wrong, you know.
He's had those knives in a steriliser.
He's got two knives there. One is for cutting through the fur,
which he's done now, then the second knife cuts the main blood vessels.
He's gone through the carotid artery there.
All the blood vessels leading to the head are now severed.
So that's the jugular vein and the carotid artery cut.
All that kicking is those muscles shutting down,
the chemical reactions.
It never gets any easier to watch, I tell you that.
Because I can see the red meat inside,
-I'm starting to think of it as...
-Yeah, as food.
'But it's not the meat that will end up on their car seats.
'It's the hide that we had come to see,
'and removing it is an incredibly skilled job.'
He's got a seam there just between the actual hide
and the fat. It's very important that, when he does that,
he hits that seam, because if he cut through the fat,
he'll disturb blood vessels. They'll actually burst,
and he won't be able to see where he's going.
You note he's making long strokes with his knife, as well.
That's quite deliberate, because he's not wanting to score the inside of the hide.
And that scoring, which is the roughness,
will mean that the hide will be worth less money,
so it's long, smooth cuts you can see he's making, yeah?
Looking a bit peaky there.
-Are you all right?
-Yeah. I'm all right.
I'm just not going to try and pretend that this is all right.
Do you know what I mean?
You're so far removed from this process.
It comes to us nicely in a little packet,
and it tastes nice, and...
..the leather, it feels nice. You don't think of it like this.
'Once the hide is completely removed, it's taken through to the offal house.'
This is the chute which the hide comes through.
That's off one of the Belgian blue heifers
that we saw earlier in the lairage. This is the back end here.
You can see the tail there, and that's the neck end there.
-When the recession hit, the price of that hide dropped to as little as £9.
-For all of that?
Yes. That's when the car industry was in trouble.
They weren't needing the leather interiors.
We were only getting nine quid for it.
'It had been a challenging and thought-provoking morning.'
During the process of programmes that I've made,
I've witnessed that, with different animals,
-about 60 times, and I don't think I want to see it again.
But every time I think about it and go round and round,
I can't think of a better way... If you're going to do this,
if you're going to eat meat, if you're going to use meat
-and animal products...
-If it has to be done that way,
that is probably the perfect way of doing it.
To find out how this mass of soggy skins
turns into a classy car interiors, we headed north to Glasgow,
home of the Scottish Leather Group,
the UK's largest producers of cow leather,
where Gareth Scott showed us around.
This is a delivery which came in this morning out of an abattoir
-in the south of England.
-It's heavy, that, isn't it?
-Whoa! That's so heavy.
-How heavy is that?
After inspection, the hide goes through a process called liming,
which removes all the hair from the skin.
How many hides can this tumble-dryer hold?
It has the capacity to turn over 3,000 hides a day.
24 hours later, the hides emerge hair-free.
That is just such a weird vision -
skin hanging there, moving around slowly.
'Next, the fat and tissue is removed from the skin.'
-Feels so rubbery.
-It's really rubbery, isn't it?
'And the remaining hide is mechanically split in two.'
It's the grain half of the hide that's used to make high-quality leather,
but first it must be tanned with chemicals to preserve it.
It's just a big drum of chamois leathers now.
-Each stage takes it further away from being a cow.
-Now it's not a cow.
The leather is pressed, dried and put through a final shaving machine
to make it thinner still.
This is it. This is the finished product.
This will go in an Aston Martin car seat.
Now that it's like this, I think, "Screw the cow."
I just think, "Look how nice it is!"
Still, you know where it came from. You were there.
But it don't matter now. We've got what we want.
-You have to remember,
the cow would never be killed for this piece of leather.
That's what's good about it - that a cow is killed for meat.
This is a by-product that happens to be profitable.
We've been through, like, tragedy, death, blood, gore -
"Ooh, this is nice!" Do you know what I mean?
To make its way onto desirable car doors,
seats and dashboards, the finished leather is pattern-cut
and hand-stitched before being fitted into every freshly minted vehicle.
And it's here that the cow arrives at its final destination.
Worldwide, 320 million cattle hides were turned into leather last year,
and over 50 million of these ended up in vehicles.
But it's not just cars that look good in leather.
SONG: "Fashion" by David Bowie
Leather and suede are staples of the fashion industry,
from jackets and shoes to handbags and belts.
When it comes to looking glam, leather is big business.
And it doesn't just come from cows, which seemed to surprise the great British public.
What do you think that is?
-Suede from which animal?
-It's fabricated, right?
-I don't know.
Or...could it be from a pig?
-It's pig suede.
-No. I don't want to wear a pig on my feet!
A pig on your feet...
-I've bought how many pigs?
In the UK, we like to leave the skin on our pigs to eat,
but a trip to Poland revealed how, elsewhere, pigs are skinned at slaughter.
You see it as a bag now.
And then the skin is turned to leather and suede.
It's more common than you might think.
About ten percent of the world's leather is made from pigskin.
And it's mostly found in our clothes and shoes.
-Feel the soft, soft suede.
-So that's pig suede?
Our wardrobes are a virtual farmyard of animals.
Sheepskin boots? Guess what they're made of.
In the UK, we purchase a million pairs every year.
And fish skin? Yep, even fish skin is used to make leather.
So it's placing the tail down, and release the fish.
Look at that!
That is amazing.
-What do we think of this handbag?
-I like it.
Oh, my God! It's a fish!
High fashion is all about looking good,
but looking good isn't all about clothes.
Cosmetics, creams, hairsprays, soaps -
the UK beauty industry is worth about £8 billion a year,
and it's absolutely brimming with animal by-products.
I took best friends Rachel and Emily to Iceland
to discover just what went into some of their favourite products.
Every other day I wash my hair, putting shampoo and conditioner in.
-'Then volumising mousse.'
-Then I have a hair serum
-for the ends of my hair.
-I would put a heat-defencing spray,
-protect it from the blow-dry.
-A curl-boosting mousse. Cover it with hairspray.
And I'd reapply it several times during the day.
-Feels really nice.
But how much do they know about what's in their products?
I do think about what goes into the products,
but a lot of the time I don't understand what's written on the back of packets.
I've been vegetarian for about 20 years.
If I found out that my favourite hair product
or contained any raw animal product,
I would be so upset.
'Iceland seemed a bizarre place for any hair product
'to start its life, but fishing marketeer Bjorn was on hand to help.'
-Say hello to Bjorn.
-Hello. Hi. Welcome.
-Nice to meet you.
-And we have to say welcome to Iceland, don't we?
-Because this is the first time.
Have you heard of a product called chitosan?
-No, we haven't.
-Chitosan is found in hair products.
-Right. I've never heard of it.
-What is it, Bjorn?
-Well, I will not tell you now.
First we will go to this boat, out to the sea,
and afterwards you will find out what it is.
We're going on the boat! It'll be an adventure. Come on, girls.
As we tried to find our sea legs, Bjorn explained that the trawler
could hold 20 tons of fish.
It goes out in rough seas for five and six days at a time,
fishing deep in the Arctic Circle.
Oh, don't film me being sick!
We were keen to fish out the origin of chitosan,
but Bjorn was playing slightly hard-to-get.
What are we fishing for today?
-Today we're fishing prawns.
Because you were asking about chitosan,
and the answer to that question is in the prawns.
-So chitosan comes from prawns?
Each haul is around two tons, and can take eight hours to sort.
Oh, my God!
'So we ventured below deck to help Bjorn with the catch.'
You use lots of hair products. You're a model.
I did not realise that they were using prawn in my hair.
-I'm never using hair products again.
You're saying that... Over there, over there, over there!
-Got one, got one, got one!
-Are you absolutely sure about that?
-This is going on my hair.
-But we don't know how yet.
I don't know how. That is true.
With that delightful thought, we followed the prawns ashore,
where they're boiled ready for processing.
Four and a half million prawns are processed here every day.
-So, what's going on here, Bjorn?
-This is the prawn-peeling plant.
Where does the chitosan come from? Which bit of the prawn?
-From the shells.
-It is from the shells? Ah!
While the meat makes its way to sandwiches in the UK,
the tough shells that protect the prawns go next door to be processed.
That is really disgusting!
Each one of these trucks contains 13 tons of shells,
packed with a substance called chitin,
which will later become chitosan.
-I'm not putting that in my hair.
-Chances are you probably have, love.
-It looks like prawn soup, doesn't it?
-It really does.
It doesn't look that appetising.
Not something at the moment that I'd want to put on my hair either.
'After we hose them down, the shells are mixed with hydrochloric acid
'to remove the calcium, then mixed with sodium hydroxide,
'commonly known as caustic soda, to remove protein and colour.'
Oh! It's like little particles of plastic.
'According to the manufacturers, removing protein
'lowers the risk of an allergic reaction to the shellfish.'
It doesn't look like a shell or a meat, or...
It smells of nothing.
The white sludge is chitin, which is pressed and dried.
-It's not still chitosan.
'From here it's processed further, into a powder, and that's it -
'Simply add water...
'ethanol, and you've got a basic hairspray.'
'So, what did the girls think?'
I don't have an issue, because I eat the prawns,
so that for me is fine. The fact that the shell is used in this way,
is this miracle product, think is fantastic. Vegetarian -
moral dilemma. What will you do about your hair product?
For ethical reasons, now I know it has come from a creature,
I'm going to go home and check all my products,
and any ones that do contain... contain the ingredient,
I think will be chucked out. I couldn't use it.
I'd imagine the prawns on my hair otherwise.
I was amazed to discover just how many hair products chitosan is in.
And when you look at a prawn shell, you can see why.
It is just so tough and flexible. It's an amazing natural material.
Once I got started, I found that the beauty industry was bursting with animal by-products.
If Rachel was upset to discover prawns in her hairspray,
I wonder what she would've made of pig in her hairbrush?
-Right, guys. Really silly question. What's this.
-What are these?
-What are they made out of?
You should know this. You work in a hair salon.
-Where do you think bristles come from?
-It's hair off an animal. Which one?
-Pig have hair?
When you read on the packets "real bristle", that's what it is.
-Oh, that's disgusting.
-You didn't know that?
Pig hair, or bristle, to give it its technical term,
has been used for brush-making for hundreds of years.
It's said to be the best-possible material to run through your hair.
Stiff yet supple, and slightly scaly in texture,
bristle removes dirt and debris
and transfers natural oils down the length of the hair
to give a natural glossy sheen.
'The hair is removed from the pigs by submerging them in scalding water
'after they've been slaughtered.'
I mean, that's just strange, isn't it?
Most of the world's bristle actually comes from China,
but I was keen to give our British bristle a go.
-Got some bags for me?
-I've got one here.
-I don't know whether that'll be big enough.
-Go on, squeeze it in!
I don't mind touching it. Very nice.
Bristle in hand, I headed off to make my very own hairbrush.
-This is rare-breed boar bristle.
-Not that much, is there, really?
-There's not that much.
-This is what we need.
-This is from China, this one?
-Ah! There we go.
-There you are.
-You see, that's not so bad!
'Well, maybe it is.'
It's not just hairbrushes that contain bristle.
It's traditionally found in shaving brushes,
paintbrushes, and, believe it or not...
Whether it's shiny hair or shiny teeth,
the chances are your beauty regime involves animals
whether you know it or not. Take lanolin, for instance.
-I've never heard of lanolin.
-I don't know what it is.
-Lanolin? What is lanolin?
-What is lanolin?
-Is it bad?
SONG: "Grease" by the Bee Gees
Ever had greasy hair?
Well, lanolin is the natural wool grease of sheep.
Can you feel it? I've handled sheep before.
-Yeah, you can feel the grease.
-It is sticky.
That's the wool grease.
'No sheep are killed in the making of lanolin.
'It's obtained by washing the wool from a shorn sheep,
'and once processed, provides a vital natural ingredient
'for face creams, moisturisers, lipsticks and balms.'
-You can see how clear it is now.
Oh, that's really sticky. That's like earwax.
But what did your shoppers make of it?
-Oh, that's weird.
-Is that weird? Is that disgusting for you?
-Not happy with that?
-I'll close my eyes while picking it up.
Just carry on. Carry on regardless. After all, it's beauty, darling!
From looking good to keeping clean,
animal leftovers make their way into all our homes,
in sometimes entirely unrecognisable forms.
'I learnt more about a hidden animal product
'that's everywhere when I visited the Lake District
'to witness a process called rendering.'
Over half a million tons of sheep, cow and pig parts
go unwanted by the food industry every year.
But they don't go to waste. They make their way to rendering sites
across the UK.
Though it's a vital job, it's a pretty grisly one,
and something that's historically been kept under wraps.
Alba Proteins kindly gave me a rare opportunity
to see rendering first hand.
Site manager Simon Boyes agreed to show me around.
Today we've got a load of sheep coming in so we can process.
Right. About how much? It's a big truck.
About 20 to 25 tons we normally receive in one load.
'The raw animal parts are unloaded into a huge bin.'
-25 tons of sheep bits and bobs!
It's pretty gruesome, you've got to say.
I mean, the blood on the floor, the fleshy bits...
It is, but what you've got to appreciate is,
this is materials which are fit for humans,
but they choose not to eat.
'The sheep parts had just started to decay,
'and were giving off a real stink.'
I haven't actually smelled anything quite as pungent
even in an abattoir.
It really sticks to the back of your throat.
'And if that lorry load of sheep parts didn't smell pretty,
'they certainly didn't look pretty either.'
Ugh, that's a lot of sheep heads.
It is. We've got sheep heads, hooves, ears,
sheep fat, and also the carcase as well.
From the bins, the parts pass into the crusher,
which has a large screw inside that pounds them into small pieces as it rotates.
You see the picture? There is the crusher.
It's crushing the material down to particle size,
and we pump directly into the cooker.
So basically that's turning it into pate.
That's right, yes. The material then goes into the cooker.
So here we have the material which is being cooked at the moment.
We heat the material up to a minimum of 120 degrees.
It kills the bacteria, flashes off the moisture.
It's like a kebab machine!
Yeah. You can see the oil being released from the material.
'The solid material goes on to be made into fertiliser
'and dried pet food, while the melted animal fat
'is squeezed out by a press and drained off.
'This is what I'd come for. It's known in the industry as tallow.'
-That's it? That's tallow?
-That's our finished product
-that we sell to the customer.
-It's like gravy.
-So there's a lot of that in there.
-There certainly is, yes.
-And that's going off to your customers?
So the million-dollar question is, who ARE your customers?
-What is this used in these days?
It forms the first ingredient of a cleaning agent.
That's a bit of a surprise. Have you ever tasted any?
-I haven't, no.
-I don't blame you.
I wonder how many people know about this product,
and how they feel about it when they know how it's made?
All right, boys?
To find out, I met up with Jenny and Laura,
who knew very little about what went into their weekly wash.
-So, you're students?
-What do you look for in washing products?
-Well, the price.
-What's on offer.
-Do you ever look at the ingredients?
Look at the ingredients on that. Do any stick out to you?
-Read that one.
-I don't even know what those words are.
-What's the worst thing it could be?
-If it was dead animal in there,
that would be the worst thing ever.
OK. This is what is in a lot of fabric conditioners and soaps.
-Oh, my God!
-Oh, I can't even look at it!
-That is disgusting.
-What even is that?
-That's sheep's head.
-It's not just sheep.
Lots of animals go into this kind of product.
-So it's in everything?
-It's in an awful lot.
It's in lots of fabric conditioners, lots of soaps.
I don't feel clean. I don't. I feel like...
-I keep looking at its little face.
It's like you're cleaning yourself with fat.
Doesn't really work out, does it?
-I don't mind it, to be honest.
-I think it's quite disgusting,
because you're wiping that all over your body.
Gets you clean, though.
Are you curious to know how something like that
-becomes this product?
Our expert will answer any questions.
'We were joined by David Howells,
'a chemist with 30 years' experience in the tallow trade.'
-What's your big question?
-Why? I just don't get it!
-Why is that used?
-How is that head used to make this?
-In that bottle.
-That's a liquid, and that's...
Because it was there. You've had your sheep. You've eaten it.
There's by-product from that. You're left with this fat.
You find things to do with it. I've got a little demonstration here.
If we put some of the tallow in here...
This is just some simple caustic-soda solution,
and instantly it's reacted. When you add salt to it,
the soap comes to the surface. Run off the water,
and you make it into a bar of soap. That's it.
Tallow and tallow-derived chemicals have a number of different names.
Just some of those to look out for on your labels include...
Or they might be listed as cationic surfactants.
When we see tallow on a label, does it always come from an animal?
It's always animal fat.
And is surfactant always from an animal as well?
No. It can be from tallow, but it can also be totally synthetic,
-a detergent made from chemicals.
-How do you know?
Unless it specifies what surfactants they are, you don't.
You have to go right into the chemistry.
It's clear that getting to the bottom of what's in our products can be tricky.
But once we know about hidden ingredients like tallow,
we then have to decide how we feel about them.
Has it changed how you think about what you buy,
-your perception of the industry?
It's really deceiving. How are you -
Sorry. I'm, like, a quick in and out, so I'll just grab what I need,
and I would never think to look at it.
But now I would definitely take a minute to look.
-I know the words now.
-Know what to look out for.
-Do you think the fact that animals have been used in these products should be labelled?
They still put on "animal testing" and "suitable for vegetarians",
"vegans", all sorts. They should at least indicate it,
because if people still want to use it, they will.
We know now but we'll still buy it, whereas if nobody knows,
then they're using it unaware, and that's a bit rubbish.
-Do you want to take the sheep heads with you?
-I think they can stay there.
Discovering that animal fats can help keep us clean
was just one of the surprises I encountered.
From products that improve our bodies
to products that claim to improve our minds,
I never thought I'd find a bit of an animal nestled in the pages of my bedtime read.
From celebrity biogs to the latest cookbooks,
we bought 55 million hardback books in the UK last year.
I was curious to find out what animal by-product
might be in these prolific page-turners.
So I recruited avid readers Andy and Emily to help me find out.
I've got a student cookbook. It's something my mum gave me
before I went to uni, like, "You may need this to survive."
Great for midnight snacks, actually.
My nan sent me a cookbook for singles.
I was, like, "Thanks!"
-Rub it in!
Before I go to bed I always try to maybe get a chapter in.
'When I'm on holiday, long journeys...'
'I read mine on train journeys on the way to uni.'
You just whip out your book and you forget about it.
You don't notice anyone around you.
I prefer hardback because my paperbacks get completely ruined.
I'd buy a hardback when it's just come out,
when it's really exciting and it's a first edition,
something like that. It makes it special.
-There's something more to it.
-It seems more of an upgrade.
Yeah, like you spent a little bit more money on it.
Although these two are never far from a book,
they know very little about how they're made,
so we headed off to Diamond Print Services,
one of the UK's leading bookbinders, to find out.
So, welcome to sunny Enfield.
You're both students. When you're reading,
do you think about how your books are made, where they come from?
It's not something you consider. It never crosses your mind.
-You just get it from the shop and it's there.
Do you think any animals are used in the manufacturing of books?
-I wouldn't have thought that at all.
-I wouldn't connect that with books.
And they're not the only ones.
-It's obviously not the paper.
-Potentially the glossy pages.
-Some sort of fish?
-Something to do with the binding?
-Maybe the letters, the print.
-The ink from an octopus.
'Back in Enfield, bookbinding specialist Nick Dingwall promised to reveal all.'
So, here we have the ingredient
that goes into producing books.
-Pretty much. All hardback books, yes.
Come on, Nick.
-There we are.
They are bones. They're a bit niffy, as well.
The glue we use to bind the books is derived from hide and bones,
-primarily from cattle.
Animal glue isn't something we make in this country any more,
but in countries like Egypt they continue to make glue as they have done for thousands of years.
In Cairo, cattle bones are collected from abattoirs across the city
and brought by the truckload to the Lion glue factory,
where they're heaped into giant piles.
The first task is to sort the bones from the horns and the hooves,
and remove any rubbish that might have made it into the mix.
The sorted bones are then placed onto a conveyor belt,
which takes them to a crusher where they're broken down
into smaller, more manageable pieces.
Next the fat has to be stripped from the bones
using a strong solvent. This process is called degreasing.
The degreased bones are now ready for the final step
in the glue-making process.
They're heated in the de-gluing machine.
The intense heat and pressure melts the collagen inside the bones,
and it runs out as a hot, sticky glue.
The fresh glue is collected in bottles ready for use.
So that's the glue. That's actually a block of animal-derived glue.
-Looks like toffee!
-And what does the packaging say on that?
The manufacturers are a little bit squeamish
about calling it animal glue, so they tend to prefer to call it
things like protein glue or jelly glue,
because essentially jelly is exactly what that is.
'Animal glue is used to stick the face paper on hardback covers,
'the decorative head and tail bands you get on fancy books,
'and any ribbons.'
So it's quite a big ingredient for you.
It's a fairly major ingredient, but it's a very natural ingredient,
and it's a by-product of a lot of other processes,
so it's the ultimate in recycling, really.
Nick got the guys making book covers to get a feel for the glue.
-That is the raw material.
The outer covering material, a front board, back board and a spine.
'The solid blocks of glue are melted to a runny liquid,
'which spreads easily but dries fast.'
And the key to this is to work reasonably quickly.
SONG: "Let's Stick Together" by Bryan Ferry
I can see it drying already.
'The animal glue is extremely tacky,
'which makes it perfect for sticking paper to card.'
-Can you smell it more now that it's melted?
It's really smelly now. It's sticking my hands together.
-It's really sticky on your hands.
-Yeah, that's looking good.
Well, depending on your definition...
-I just wanted to finish first.
I wouldn't necessarily put it round a book we're going to make, but...
We were kind of going for that.
It's fairly important that we've got a nice, smooth, even finish,
no bubbles and things like that.
-And, you know...
-There are a few bubbles.
There are imperfections here and there.
'OK. Time to see how the machines do it.'
To give you an idea of exactly how much adhesive should be on there,
that very thin film on this rotating drum
-is actually the amount of adhesive.
-Very fine layer.
Very, very thin layer.
'At one end of the casing machine,
'the cardboard's fed in and cut into three pieces.
'At the other end, the face paper is fed in over the drum,
'which applies a thin layer of animal glue.
'The board and the paper are then pressed together
'and the edges folded up.'
Slightly neater job happening there, isn't it?
And there we are - stack of finished cases.
-They are better.
-That's much nicer.
That's so neat and lovely, isn't it?
It just feels like a quality product.
'Next the pages must be stuck into the case,
'and more animal glue is used to attach the ribbon
'and the head and the tail band.'
-How much glue do you get through?
-In normal running,
on a book like this, 3,500 books in an hour,
we would probably only use one pack of this.
That's quite good, isn't it? It's more efficient than your gluing.
The vast majority of hardback books use animal glue in their binding.
But we were curious to learn why, when there are other glues available.
There are synthetic glues out there, so why is it so widely used?
The synthetics that are available
are derived mainly from the chemical and oil industry.
They're things that are going to run out at some point,
and this is still a completely organic,
-completely recycled material.
-Does it make it cheaper?
Absolutely. Oil prices, chemical prices are increasing,
but as a natural, recycled product, this is something
that we can continue to use, and it's reasonably cost effective.
Our tour was over. But before we left, Nick had a present for me.
We've got something for you, just about to be delivered out now.
-Ah, yes! My lifetime's work!
'It was just a gag of course,
'but what did other people make of books stuck with animal glue?'
It's quite a shock, to be honest. You wouldn't think that happened.
I think it's really disgusting.
I don't know. I don't quite like the idea of that, to be honest.
I think it's all right if it's a by-product of meat.
Doesn't bother me. I eat the meat. Why would I not use the glue?
I wouldn't associate a cow with a book, but it's resourceful.
-Will this change anything for you?
-Um, not personally, no.
I'm still going to read books.
I'll probably think about it when I open a book,
and I'll probably tell my friends, but I'm not a vegan or anything.
It won't make an impact on my life.
Especially with some books, you can only get them in hardback,
and what are you supposed to do? If you really want it...
So next time you're sitting on the sofa, nose in a book...
-..are you going to be as enthralled with the storyline,
or will you be looking at the cover?
I won't have my nose quite so deep in the book this time.
Animal glue isn't just used for the binding of books.
It's also used in the manufacture of some trainers,
board games, puzzles and playing cards.
Chances are you're handling part of a cow every single day.
Work or play, animal by-products are never far away.
I found our leisure pursuits littered with animal parts.
Which part of a tennis racquet do you think might be made from an animal?
-I'd say the strings or the handle.
-Maybe the strings.
-I think the strings.
-Made of skin?
-Cat liver or something really weird?
It may be whiskers wrapped round.
The gut is my only guess.
The strings on some tennis racquets are indeed made from the intestines of cows.
-Have a go. Look.
-Oh, yeah. There you go.
Er, yeah. It's just pasta. It's fine.
How many of these would go into a tennis racquet?
Five is one cow.
-So how many...
The soggy intestines are cut into long ribbons of gut,
which are washed, wound together tightly...
..and then dried.
These strings have been here for one week.
They have to be dried very slowly.
Once they're varnished, they're ready to use.
These strong, elastic gut strings are favoured over synthetic strings
by many of the world's pros.
Sheep's guts, meanwhile are used for an altogether more amorous activity.
-Do you know what these are?
-I know what that is.
I'm not too sure!
-What do you think that's made out of?
-What is that - plastic, or...
-I'm not sure.
-Is that intestines?
-It is indeed.
-How do you feel about that now?
Is that what they used to make them out of?
-I tell you what, gents - take one.
-Oh, thank you. Ever so kind.
-Let me know how you get on.
-What time do you finish?
Though these old-fashioned condoms may help to prevent pregnancy,
they don't protect from STDs, so for the safest sex,
it's best to stick with the more modern variety.
Even when it comes to pleasure-seeking,
it seems that animal by-products are involved.
I met up with some rugby boys from Canterbury
to find out which animal organ is involved in their favourite pastime.
SONG: "Tubthumping" by Chumbawamba
You come to uni and you want to join the rugby team,
people just expect you will be drinking.
Our drinking team has a rugby problem.
An away match, we'd start drinking as soon as we'd finished the game, in the changing rooms.
'Hopefully we've had a win, and we're all in good spirits. Start drinking there.'
There isn't much I wouldn't drink.
-I'd drink urine out of a pint, dog food, sick...
Would an early start at Billingsgate fish market be enough to put them off their booze?
-Temi. Morning, lads. Morning. How we doing?
-It is early. What do you think we're doing
-at this ungodly hour?
-At a fish market,
something to do with beer... Not a clue.
There's a product in beer called isinglass, apparently.
-From a fish, or...
-Yeah, from a fish.
-All right. Cool.
-What do you think about the fact
that there's something fishy in your beer? Does that put you off?
-Cos you don't know what it is. Shall we find out how gruesome it is?
-OK. Come on.
I think you'll be all right.
Maybe CJ Jackson, the director of Billingsgate Seafood Training School, would enlighten us.
CJ, we know that there's something called isinglass in beer,
-but what is it?
-It actually is a dried swim bladder of a fish.
-What's a swim bladder?
-It's like the buoyancy aid.
It basically keeps round fish upright.
In the 18th century they used to take the swim bladder from a beluga sturgeon.
Today beluga sturgeons are really endangered,
so what they're using now is a fish called Vietnamese catfish or Pangasius.
What CJ hadn't told us is that Pangasius can grow
up to three metres long. As it's hard to find whole ones in the UK
we were going to see the same principle on a much smaller scale.
Say hello to Gary the gurnard.
I'll hold on to the tail.
I'm going to insert the scissors into the back of the head of the fish.
And then just gently push... CRUNCHING
-Not liking that?
-No, not at all. Wasn't nice.
It's not that bad. Man up.
Bend the fish down.
-I don't want it to splat on me.
-It's not going to splat on you.
Then I'm going to put my finger in there and gently ease back...
SQUELCHING The swim bladder is full of gas,
so it's intact. So you can see the swim bladder.
-Bend it. Pull it up.
-Ooh, there you go. I've got...
-Look at the bladder.
-There's one as well.
-That's the bit you're going to use.
What I still don't quite understand is how it's used in beer.
Well, I know they dry it, but when it comes to the actual function
and how they actually use it, you'd need to speak to a brewer.
Beer historian Peter Haydon agreed to show us round his specialist brewery in Greenwich,
Contain yourselves! We're going into a brewery.
Mmm, nice smell!
This is a fish maw.
-Which is a swim bladder.
Which is the raw material from which we make isinglass.
It's a protein called collagen.
-It's the same thing as some ladies like to put in their lips to make them bigger.
-Don't look at me.
It's a very pure and natural form of protein.
So how does that end up as isinglass?
There are a couple of manufacturers in the UK who produce this
for the brewing industry. They will take the raw material,
process it firstly into a powder,
or, in the format that we're going to use it,
as a much more liquid format.
Could I drink that, or would I get ill?
-You can drink that.
-There you go, gents.
-Oh, that's horrible.
Can we see this in action now,
-how it actually works?
-By all means.
Isinglass is used in the production of many cask ales,
some stouts and a few lagers.
Yeast cells in beer make it cloudy.
Normally it would take four days
for these cells to sink to the bottom of a keg,
leaving a clear beer. Adding isinglass speeds up this process,
as it attracts the yeast cells into heavy clusters
which sink to the bottom in just six hours.
So, Kev, if you want to do the honours...
-So the swim bladder is at the bottom of that keg?
'So, if isinglass falls to the bottom of the barrel,
'is there any of it left in the final drink?'
-You insist it's not part of the beer, not part of the mix?
'Studies agree that in most cases isinglass is undetectable in the finished pint.
'But some bottle-conditioned ales and cask ales,
'if served from too near the bottom of the barrel, may still contain minute amounts.'
I found the whole process today really interesting and fascinating,
but it hasn't put me off at all.
When you were cutting open the fish and saw the blood and guts,
but when you see it all dried out and then the liquid,
-it doesn't put me off.
-I was a bit squeamish to start off with.
To be honest with you it's part of my life, my lifestyle, so I won't give it up that easy.
-Good day. Thank you. Cheers.
Who would have thought a fish bladder could brighten up your beer?
In the surprising stakes, isinglass was right up there,
but it wasn't perhaps the most noble use for an animal by-product.
A trip to Southampton airport revealed a protein from cow hoofs
is used to make special aviation firefighting foam.
A protein is extracted which is turned into a concentrate,
which we mix with water and air, which produces the foam.
Have a sniff.
Oh, my God!
The power! It's so forceful!
The kickback from the hose is amazing!
My face is on fire!
Meanwhile, in a hair-raising textile experiment,
we put sheep's wool to the test. Set alight alongside polyester,
wool proved itself nature's finest fire blanket.
Less toxic smoke, no dripping. No dripping at all.
It's self-extinguished, so it's not actually having to put out a fire.
-Are you surprised, Dan?
-I thought it would be a wall of flames.
It turned out that some animals and their by-products had lifesaving properties,
none more so than the pig.
'I was intrigued to discover ballistics experts use blocks of gelatine,
'made from pigskin, as a substitute for human flesh.'
That is so strange.
'Analysing the impact of bullets helps them design better protective clothing
-'and medical care for our troops.'
Because pigs are so similar to humans in their anatomy,
they've proved extremely useful in the field of medicine.
'I met 19-year-old Glaswegian Robyn, who might not be here today
'were it not for the pig.'
Last year I was diagnosed with a heart condition
called aortic stenosis. It came totally out of the blue,
because I've been working out since I was, like, 14.
I was doing a fitness test at college.
It was the mile run, and I couldn't stop coughing after it.
So I went to the doctor.
I was sent off for ECGs and heart scans.
I had this rare heart condition and I needed heart surgery.
The main valve taking blood from Robyn's heart to her body
was critically narrow. It would have to be replaced.
I was told that if I carried on doing my fitness,
I could have been a goner in a year's time.
I came out of the surgeon's office just totally devastated.
They had to take my own aortic valve and replace it with a pig's one.
They chose the pig's one because it's most similar to a human valve.
I was shocked to know you could do stuff like that,
they could take bits from animals and put them inside a human.
-How you feeling?
-Little bit nervous.
'To find out more about the piggy part Robyn has inside her,
'I took her to meet Dr Dan Tucker at Cambridge University veterinary school.'
-Nice to meet you.
-You're in charge of our dissection today?
I am. Before we go through into the post-mortem room
we need to put some protective clothing on.
Dan and his team routinely conduct post-mortems on animals
who've died of unknown causes.
The pig on the table unfortunately had to be put down
because of a painful lameness problem
which Dan had been asked to investigate.
In terms of anatomy, pigs are very close to humans, aren't they?
Absolutely. Blood pressures in the pig are remarkably similar
to people, because after all, we live similar lifestyles,
mainly sedentary. We forage around for food and then we go to sleep,
and so the whole metabolism is the same.
'Dissecting the pig gave us the rare opportunity
'to see the heart in detail.'
These are the lungs here. This is the heart.
'It was an emotional moment for Robyn as the organ was cut out.'
This is the aorta. It's a very thick-walled, elastic structure.
And down in the gloom of there you can actually see the aortic valve.
'Carefully dissecting the heart gave us a better look at the valve.'
When you hear your heartbeat, what are you listening to?
If you think of the heartbeat as being a "lub-dub, lub-dub",
the "dub" is the closing of the aortic valve,
and your pulse is the shockwave of that aortic valve closing.
Robyn, about 18 months ago, somebody was doing this with a pig heart,
-preparing a valve for you.
I wondered if they're, like, already there...
-Gentlemen, are the valves ready and waiting?
-And then somebody picked yours. "This is the one for Robyn."
-I suppose so!
This is the bit that was transplanted over to you.
-That is incredible. Do you want to hold it?
'Cutting it open revealed the three tiny leaflets
'that make up the valve and keep the blood pumping round our bodies.'
Do you see now these little cusps? They're like little half-moons.
They're little pockets, very, very tough, fibrous tissue.
-They look very delicate.
-They look like little petals.
If it wasn't for these, as you know, you can't cope.
It's funny something that small saved me.
That's keeping you alive. That's why you're standing here now.
Robyn's heart-valve replacement operation was pioneered
over 30 years ago.
At King's College Hospital, London,
top cardiothoracic surgeon Olaf Wendler
performs the skilled procedure every week.
To gain access to the heart and the aortic valve,
we need to open the chest.
This is done by sawing through and splitting the breastbone.
A piece of heart membrane is carefully cut away
to be used later in the operation.
The patient is then attached to a heart-and-lung bypass machine,
which will take over circulation during surgery.
OK. Start up on bypass.
A solution is used next to chemically stop the heart
while the aorta, the largest artery in the body, is cut open.
The damaged aortic valve is then carefully cut away,
and the pre-packed pig valve prepared.
The new heart valve is delicately inserted into position
and carefully stitched into place using the membrane cut away earlier.
The aorta is reconnected, and as blood is reintroduced
into the heart, it begins to beat again.
We have normal blood supply of the heart again.
The heart-lung machine is still pumping.
The blood now goes also into the heart itself again,
starts again purely due to the fact
that normal blood supply is re-established to the heart
and enables the heart cells to produce a heart rhythm again.
The pig valve is working, and the chest is neatly closed.
Because you're a vegetarian,
did you ever question whether you would accept part of an animal?
I didn't question it at all when it was a matter of life and death.
I don't think anybody would think twice about it.
-I'm just happy to be standing here.
-Absolutely. We're happy as well.
Thanks, little piggy.
The lifesaving ability of the pig heart valve
surely makes it the most important animal product I've encountered.
And it's just one more example of the ingenious ways
I've seen leftover animal parts transformed into something useful.
What's amazed me is not just the huge number of animal products
all around us, but the fact that the bits of animals we don't eat
have so many valuable natural qualities
that we can exploit. And given that we farm these animals,
to me it seems sensible, and almost a moral duty,
that the bits don't go to waste.
Subtitles by Red Bee Media Ltd
From the sheep parts hidden in your soap to the fishy ingredient in your favourite pint, though you probably don't know it, the bits of the animals we don't eat for dinner often end up being made into the products we use everyday.
Julia Bradbury goes on an eye-opening journey to find out how. She is joined by the young consumers who use these products to uncover the surprising animal origins of our most popular items by following the transformation of each leftover body part all the way from the abattoir to the shop floor.
In this concluding programme, Julia revisits her highlights from the series and discovers which animal part is used to produce our bestselling books.