Milk Inside the Factory

As a nation, we consume over 20 million litres of milk every day.

And right now, factories across the country are processing

milk from nearly two million cows.

It's a modern-day miracle that we all take for granted,

but it's a race against time.

Cow to carton in 24 hours.

How do they do it?

Well, tonight we are taking you inside one of the largest

fresh milk-processing plants on Earth to find out.

'I'm Gregg Wallace and I have been given exclusive access to see how

'this dairy factory can process 2,000 litres of milk

'in under a minute.'

We've got raw milk here, we start to warm it up, warm it up

and then we homogenise it.

'How cutting-edge science is used to create the perfect drop.'

We do a bit of a taste, just like you would taste a good wine,

it's just milk.

'And how new technology will change the future of milking.'

Mate, I love this. I absolutely love this.

'I'm Cherry Healey. I'll be following the milk off-site to show how

'it makes cheese on an epic scale.'

Now this is where we see the curds and whey.

Oh, whoa! Eugh! Eugh, that's like scrambled eggs.

'And revealing how milk makes the nation's favourite dessert.'

That may be the most beautiful thing I've ever seen.

COW MOOS

Along the way, historian Ruth Goodman will

investigate our complicated history with the white stuff.

With the invention of the steam engine

we could bring their milk at top speed into the cities.

'We'll be meeting robots.'

Whoa, whoa. Argh.

'And people who have worked in dairies all their lives.'

Been in this business 18 years, in a fridge.

I effectively was a robot.

Most days, 1.5 million litres of milk will pass through

here on the way to your supermarket shelf.

This is the incredible story of the factories that feed Britain.

Tonight, I'm going to show you the remarkable journey of milk

through Arla Dairies, one of the biggest producers of milk,

cheese and butter in Britain.

It's a cooperative, owned by 13,500 farmers across Europe,

including Neil and Jane Dyson.

They're cute, aren't they?

I've come to their third-generation dairy farm in Buckinghamshire

to see how it all begins, with a herd of 500 Holstein Friesians.

Here's your Uncle Greggy, I've come to give you some lunch.

The Dysons rear 120 young heifers a year

that are specially bred to produce milk.

How do we go from baby cow to milk?

When they're 15 months old, they'll get pregnant for the first time.

Then they'll have their first calf when they're two years old

and then they'll start producing milk.

Cos obviously - no calf, no milk.

How can you guarantee that every different heifer is going to

fancy the same looking bull?

It's not been a problem in the past.

After calving, cows produce milk for nine months,

then they need to be artificially inseminated to keep having

more calves and keep producing milk.

I have to confess to being slightly uncomfortable with so many big cows.

-Oh, yeah.

-700 kilos.

Don't let 'em get me.

That one's going to slip over, fall over and crush me.

Come on, girls.

'Milking starts at 4.30 in the morning,

'and every day the Dysons milk for 16.5 hours.'

This one's hiding at the back, come on.

I'm going to help.

Are you ready?

No, I'm a little bit nervous.

It's not tricky once you've done it a few hundred times.

So you're now looking at the backside of 34 cows.

Would you like to choose your cow?

This one.

OK. You hold her there and you squeeze down.

Before we can get started

we need to check for something that all dairy farmers fear.

Right, her milk's good.

If she's got mastitis, which is an infection,

then it would be watery with horrible clots.

If they have mastitis, we must make sure we give her some antibiotics.

And if we do that then she mustn't be milked with the rest of

the cows, she must be kept separate, cos you and I must not have

that milk that's had the antibiotics in it, we must throw that away.

Put your finger inside here.

And can you feel pulse, pulse, pulse?

Yeah, yeah, yeah.

That's the sucking, like the baby calf would suck you.

Take this and put it onto her teat.

You can hear it sucking, can't you?

Oh, that's it. Yeah, that's it. You got that one.

You're OK. There you go.

Number three and number four.

And, if you look in here, you can actually see the milk.

In around 24 hours, this milk will be bottled and ready to drink.

Do you refrigerate the milk straight away?

Before it goes into our big tank it's cooled to three degrees C.

When there's no more milk coming out

the machine stops milking automatically.

There it goes, automatically off.

THEY LAUGH

I'm never going to see a bowl of breakfast cereal

in the same way again. Ever.

The Dysons' cows produce 12,000 litres a day,

which is destined for the enormous dairy factory 13 miles away

in Aylesbury, Buckinghamshire.

1.5 hours after milking, Paula Da Silva Pereira arrives

to collect the milk in an insulated tanker

which will keep it chilled at around three degrees.

The Dysons are paid according to the quality of the milk,

so a daily sample needs to be taken.

What do we want in the milk?

We want good fat. We want high protein.

I mean, what does it vary by?

It could vary by 10%, which doesn't sound a lot,

but for us it could mean a penny or two per litre.

12,000 litres, every day.

-That could be the profit.

-Yeah.

-Perfect.

-Do we test this or does this go off now?

-It goes off, yeah.

-They don't trust us to test it?

-No.

Well I'm a food and drink expert, as you know, and let me tell you...

this milk looks really good to me.

-Oh, brilliant.

-All right. Don't worry about a thing.

Come on, Gregg.

Oh, crickey.

It's like being a fireman.

I'll catch up with the Dysons' milk later at the dairy factory,

after Paula has finished the remainder of her 96-mile route,

collecting from two other farms.

Well, there's a truck full of milk just left the farm, but that is

just one of tens of thousands delivering milk all over the nation.

And we go through milk in huge quantities.

Actually, the fact that we can drink milk in that much quantity

really makes us quite unusual.

Almost all of us can digest milk as babies,

it's a trait we share with other mammals.

But, amazingly, there's only one mammal that can keep

digesting milk into adulthood and that's us.

Even then, as much as two thirds of the world's adult population

find milk difficult to stomach.

Every time you try and get to sleep,

it feels like a witch's cauldron's going off in your stomach.

If I have a lot of it then I can spend some time in the bathroom.

What is it about milk that some of us can't tolerate?

Whole milk is made up of 87% water,

8.3% protein, fat and vitamins combined

and 4.7% milk sugars, called lactose, which can cause problems.

During childhood, many of us stop producing an enzyme called lactase

which helps break down the milk sugars

and they become lactose intolerant.

It's a condition that's surprisingly common.

About 50 million Americans struggle to digest milk.

In the South of France, half the locals must say "non"

to a glass of the white stuff.

And for the Chinese, astonishingly, 90% of them are lactose intolerant.

So why is it that so many people in the world have a problem with milk?

The man who should know is Professor Mark Thomas.

He's been studying evolutionary genetics for 22 years.

What is this?

OK, so this is the piece of DNA sequence around the bit that

controls whether you digest the sugar in milk.

So, this DNA sequence is what most people have?

Most people in the world, yes.

And most people who have this DNA sequence cannot digest lactose.

-That's right.

-They cannot drink milk?

That's right. As adults.

So, if the norm is to not be able to drink milk, what happened?

How come most of us here in Britain can?

Well, we're unusual.

People in northwest Europe are generally what

-we like to call freaks of nature.

-SHE LAUGHS

Scientists think the reason most Europeans can drink milk,

is because of a random genetic mutation that

first occurred in Hungary thousands of years ago.

There's been a change in this DNA sequence

somewhere in the last 10,000 or 12,000 years.

This one here will be changed to that.

And that's only one in 3,000 million of these letters in your genome.

-It's just one, just that one change.

-That's it?

-That's it.

-That's the difference between me

-being able to have a milkshake or not?

-Yeah.

Some theories suggest being able to drink milk would have been

a huge advantage in times of famine.

You were much more likely to survive

if you were able to digest such a nutrient-rich food.

So the lucky mutation from C to T in the gene sequence

quickly spread across Europe where most of us can now drink milk.

So, do I have this genetic mutation that makes me tolerant to milk?

A few weeks ago, I took a simple home DNA swab test to find out.

I sent it off to the lab and I believe you have the results.

I do indeed, yes.

I wish I had a drumroll or some kind of crescendo, but I don't.

Right. So you are...

Yay, I'm a mutant.

-You are, you're a mutant.

-Hooray.

Not only are you a mutant, but you are a mutant-mutant.

You actually get two copies of this, one from your mother

and one from your father.

So you get a double shot at being able to digest the sugar in milk.

Wow, I want a double latte...

Yeah, there you go, an excuse for a double latte.

-..to match my double genetic mutation.

-Exactly.

So one single mutation that I and most people in Britain

have in our genes has turned us into a national of milk lovers.

Pretty good for a random chance.

To see the next stage of milk, I've got to look the part.

-LAUGHING:

-Yeah!

I am at one of the biggest fresh milk dairies in the world.

200 people work 24/7

processing up to a whopping 650 million litres a year.

Enough to fill 260 Olympic-size swimming pools.

And two hours after leaving the cow,

the milk tanker full of the Dysons' milk is arriving.

It's one of the 75 tankers that deliver to the

milk intake area every day,

overseen by technician, Colin Keyes.

Give me some idea of the scale.

How much milk is coming through here?

Well, roughly, this site does about 1.5 million litres a day.

See, it's really hard for me to get my head around that sort of scale.

It's massive, it's massive.

There's Paula. You all right, love?

-Hiya.

-What happens there, Colin?

I'm going to make sure the milk that goes to the customer

is good quality. That is my job.

You're the bouncer.

-I am the bouncer.

-Nothing bad gets past you.

I'm not a very big bouncer, but I'm a bouncer, yeah.

And what Paula's going to do is get a sample.

So why are we checking again?

You just checked one farm, but now you've got other farms

throwing in their milk where it could be contaminated.

We check it before we know whether she can unload it.

That's right, because if we don't check it,

the milk goes into the system and we don't want that.

Will you send the truck away if it's not right?

Yes, it will be rejected.

If the temperature was incorrect, it's gone, the whole lot.

If it's over eight degrees, it's gone. Antibiotic failure, it's gone.

24,000 litres of milk will be rejected on one farm messing up.

Mate, that is mental.

I'm going to check your milk and we'll be right back

to let you know whether you can unload it or not, OK.

OK, perfect, I will wait.

We need to do a bit of a taste.

With all this millions of pounds' worth of kit here,

you still have to taste it?

Yeah, I have to taste every single tanker.

I just microwave it, we're basically pasteurising it.

Just like you would taste a good wine,

this is like a...it's just milk.

And you smell it. Smell that. It smells malty.

It smells good, doesn't it?

It smells like a bedtime drink I had as a kid.

Exactly, exactly that.

Just checking for any taints, can you taste anything?

Does it taste nice and clear and good?

It tastes absolutely lovely, I just want to put some sugar in there.

-It does taste good.

-Can we cook up some more?

We can have as much as you want, Gregg.

Put some chocolate powder in there, it'll be excellent.

That tastes very good.

Now I am going to check there's no antibiotics in the milk.

So I'm going to put it on a heating block, 180 seconds.

We're testing for antibiotics, what is the danger to us?

We don't want antibiotics in the milk chain

so people sort of become immune to the antibiotics.

Now I understand why you get so strung up about this stuff.

We do.

Antibiotics are given to cows that are sick, just like humans,

and need to be carefully controlled.

By using an indicator strip, Colin can tell

if antibiotic molecules are present in the milk.

We've got the fat line at the bottom and the thin line at the top,

so we know that the milk is a good quality.

We can go out to the tanker now, we can open the valve,

push start and get that milk into one of those silos.

I knew that lot would be fine, because I actually helped milk them.

Two hours, ten minutes after milking,

thousands of litres of Dysons' milk can now be pumped

into one of the 12 raw milk silos that I'm underneath.

HE CHUCKLES HAPPILY

Yeah. There's 300,000 litres above us in each of these silos.

Between them, these silos can hold over six million pints.

It's a little James Bond.

It is a little James Bond.

But I feel a little bit uncomfortable underneath such

-a volume of liquid.

-Yeah, yeah.

If that now split open, I'd know what a Coco Pop feels like.

LAUGHING: Exactly.

The Dysons' milk is stored

in these raw milk silos for almost 16 hours,

waiting for its turn to be processed.

Once released, the critical next stage is the processing zone,

where raw milk is treated under the watchful eye

of process technician, Mario Salvador.

Welcome to the process control room.

What on earth is this?

Well, the thing is that in this process control room,

things happen very fast.

One drop of milk is able to go from that silo into this silo,

which is finished milk, in 55 seconds.

So let me get this right. We have got raw milk here...

-Yeah.

-..and it'll go through all of this.

In 55 seconds' time,

it's milk in here, ready to be drunk by me the customer.

-That's correct.

-Are you lying to me?

No, definitely not, I'm going to show you.

This is the processing floor,

where the Dysons' milk arrives 18 hours, ten minutes

after leaving the cow.

Here 1.5 million litres of milk, enough to fill two jumbo jets,

is treated in over six miles of pipes

by a state-of-the-art, fully-automated system

running 24 hours a day.

When you see all of this hi-tech machinery

it's easy to forget it's actually coming from the cow.

All the milk here is put through a four-stage process,

starting with separation, then standardisation,

homogenisation,

and finally, pasteurisation.

The first thing we need to do is to get rid of the fat.

The milk comes into this machine which is separated.

That is spinning around at 4,500rpm.

All the fat globules will go in the top, the skim will go at the

bottom and we're going to be able to separate the fat from the skim.

You take all the fat out at this stage

-and then you can put it back in again.

-At the end, yes.

Once the milk is separated

it needs to be precisely standardised

by now adding some fat back in.

In the standardising machine, the computer controls how much

fat is added back into the skimmed milk.

3.5% for whole milk, 1.7% for semi-skimmed,

and unsurprisingly, 0% for skimmed.

But the next problem they face is the fat won't mix evenly.

If you have a lot of raw milk and you leave it for a few hours,

you're going to have a line on the top.

We don't want to do that, we want a perfect solution, clear and white.

To solve this predicament, the next step is homogenisation,

which became common practice in the late 1980s because consumers

preferred their milk without a layer of cream on the top.

The milk is forced through small holes at high pressure,

smashing the fat globules till they become tiny and dispersed.

That cream that we used to get on the top of the milk,

-that doesn't happen anymore.

-That's not going to happen.

The final step is pasteurisation,

which kills off the majority of bacteria in the milk.

This is happening on these plates, so what we do here is

we heat up the milk, up to 74.5 degrees

and then the milk goes through, very fast,

through those pipes for 28 seconds

at 74.5 degrees.

-And that's pasteurisation.

-That's correct.

Let's see if I can beat the milk in this 55-second process.

So we've got raw milk here, all right.

It's flowing through here, then we start to warm it up,

warm it up through these pipes, down to here where we separate the fat.

Then we decide whether it's going to be skimmed,

semi-skimmed or full fat.

-We start to add the fat back in and then we homogenise it...

-Yes.

..so that we mix all the fat in with the milk

so that we don't have the fat layer on top of the milk.

Then we need to pump it back over here.

-We heat it.

-Yes.

-78 degrees.

-That's correct.

-28 seconds.

-74.5.

74 degrees, 28 seconds, right, then we've pasteurised it.

Now we've got to chill it so we can use it.

And that's five degrees and that's over here.

-All of that in one minute, how did I do?

-Very good.

The Dysons' milk has now moved into a chilled holding tank, to be mixed

for about 30 minutes before the next stage of its remarkable journey.

Who knew all that? I most certainly didn't.

You see a cow, you know it produces milk, you think it goes in a carton.

I had absolutely no idea how milk goes through so many processes.

I've seen how pasteurisation, which we take for granted,

is such a crucial procedure in milk production today.

And historian Ruth Goodman is discovering how this process

has saved hundreds of thousands of lives.

Before the Industrial Revolution,

most people drank their milk raw, meaning straight from the cow.

And wherever you lived, you were never very far

from one of our four-legged friends.

But all that was about to change with

the arrival of the Victorians and their incredible machines.

As Britain steamed ahead towards the late 19th century,

a network of railways moved milk

hundreds of miles around the country.

With the invention of the steam engine, the cows could be out in the

countryside and we could bring their milk at top speed into the cities.

It seems a perfect win-win situation,

but this new efficient distribution method had one fatal consequence

and that was the spread of bovine tuberculosis, TB.

In the 19th century,

tuberculosis was the biggest killer in Western Europe.

Bovine tuberculosis was a variant that could be

caught by drinking raw cow's milk.

And raw cow's milk was being efficiently delivered all over

the country by rail.

The problem was one of contamination.

The milk from a large number of different cows

was mixed together in churns,

which increased the risk of infection.

Peter Atkins, Professor of Geography at Durham University, has been

looking into how devastating this was for the British population.

How many people were affected by this?

In the period that I've been looking at, 1850 to 1960, something

like 800,000 dying from bovine tuberculosis for Great Britain.

Because they were drinking more milk than any other

group in the population, we're talking here about young children.

If you had milk from that churn,

it would have been possible to catch tuberculosis

because of the mixing process.

In the 1920s, the churns changed to special milk rail tankers

which were glass-lined for hygiene

and cork-insulated to keep the milk cool.

When they moved over to the big tankers,

you've got lots of milk all being mixed together.

I mean, this must have made the problem a lot worse?

From 1926 onwards, that's correct.

With 1,000 cows, that milk tanker was still infected

just by one cow that had tuberculosis.

It's a disease which can be diluted many times over.

'Back in 1864, scientist Louis Pasteur discovered that

'heating wine would kill most of the bad bacteria.'

A pan of hot water.

'The process was named after the man who invested it -

'pasteurisation.

'A method that could be used to kill the tuberculosis microbes in milk.'

So, this is our unpasteurised milk straight from the cow.

'It was so simple and effective, we still use this method today.

'But people in the 1930s and early '40s were very

'distrustful of this potentially life-saving option.'

Considering it is such a simple process,

why do you think people were so reluctant?

Yes, it's strange, isn't it?

I think there's some reluctance on the part of the consumers.

Some of whom think that the ingredients of the milk

are being damaged, such as the vitamins for instance.

Incredibly, it wasn't until the 1960s that it became the norm

to pasteurise milk in the UK. And even to this day,

it's not compulsory in England and Wales.

So just a matter of lifting it from the hot water...

..into the cold.

The pasteurising of raw milk and the introduction of compulsory

TB testing in cattle, which eradicated cows with TB,

reduced the number of cases of human tuberculosis.

By 1960, most cattle were free of the disease and the risk of

bovine tuberculosis to the human population

is now a thing of the past.

Back in the Aylesbury factory,

we've just pasteurised our milk on a massive scale.

Now, over 18 hours and 35 minutes since it left the cow,

Mario needs to take another sample of milk

to make sure the processes have worked.

If this passes the test,

-this is virtually supermarket-ready milk, right?

-Yes, that's correct.

First up, he is testing that this enormous batch of

semi-skimmed milk has the correct 1.7% of fat in it.

On this equipment, this is able to tell me

how much fat it is in the sample. That was semi-skimmed milk.

And as you can see on the screen, standardisation passed is correct.

'Next, he needs to make sure that it's been homogenised correctly.'

So we just need a single drop of milk.

'With no signs of fatty lumps.'

As you can see, the fat globules, all of them

have got more or less the same size, they're very, very small.

If you compare the raw milk, the fat globules are big.

So we can say that the milk has been homogenised properly.

Now we have one more thing to do,

we need to taste it and make sure it tastes nice.

-Yeah, that's the semi-skimmed milk I buy.

-There we go.

With the press of a button,

98,000 litres of milk is released

into one of the 12 finished milk silos,

18 hours, 39 minutes after leaving the cow.

Do you know what, I can hear it gushing.

To ensure a constant supply, milk gets stock piled here

for up to five hours, waiting for its turn to be bottled.

While I'm being totally gobsmacked by the massive volumes of milk

processed so quickly,

Cherry is busy investigating how cheese is made on a mammoth scale.

While the vast majority of milk ends up in our fridges

just days after it's left the farm, some spends months,

if not years, at cheese factories like this one.

Here in Taw Valley, Devon,

is one of the largest cheese factories in the UK,

making an enormous 100 million blocks of cheese a year.

Rob Whitely, process manager, is going to show me how it's done.

Wow. What is that smell?

So that smell is the start of the cheese-making process.

That is strong. If my eyes start to water, will you let me know?

I can't smell it, so I must be used to it.

THEY LAUGH

So what is going on here? These vats are enormous.

We've got ten cheese vats here. Predominantly we make cheddar.

In a year,

-we will make approximately 37,000 tonnes of cheese.

-Wow.

A million litres of fresh milk comes through this factory every 24 hours.

Here it comes, wow.

Oh, my goodness, that is an unfathomable amount of milk.

They'll be 20,000 litres of milk in this vat.

Absolutely amazing.

To make cheese on a monumental scale like this,

you need a lot of a rather surprising but crucial ingredient.

Once we've started putting the milk into the bottom of the vat,

we then need to add the bacteria to start producing acid in the cheese.

These good bacteria feed on milk sugars called lactose

and transform it into lactic acid.

And we isolate particular strains depending on what

characteristic we want in the end cheese.

A bit like when you're making a curry

-and you use spices to flavour it?

-Yes.

-That's how you use bacteria?

-Exactly like that.

-Like a chef?

-It's like being a cheese chef.

And it's the bacteria that these chefs use that determine

the characteristics and flavour of a good cheese.

-All in.

-Excellent.

Now the process of producing cheddar on an epic scale

can continue.

A milk-clotting enzyme called rennet is added.

This, together with the lactic acid, helps to separate the milk

solids, called curds, from the liquid, known as whey.

So this is where we see the curds and whey.

Oh, whoa, eugh! Eugh, that's like scrambled eggs.

-What we can do is take some out and show you.

-Oh, it's warm.

It's like porridge and scrambled eggs, that's extraordinary.

The whey is then drained off, leaving the curd

which is heated and stirred to squeeze out yet more whey.

The massive curd is formed into huge slabs.

Oh, wow.

All this time the bacteria have been feeding on lactose in the milk,

but now they need to be controlled.

So we add salt to then arrest the action of the bacteria.

Because if we let the bacteria continue, they would actually

destroy the cheese.

We don't want that to happen.

We want to close them down, they've had a bit of a party,

now it's time for them to wind down a bit.

Finally, the salted curd is compressed into blocks,

vacuum-packed for protection and ready for maturing.

400 years ago, cheese makers stored cheddar in caves, which are always

cool with high humidity, ideal to stop the cheeses drying out.

Some cheeses are still matured that way.

But here, next door to the factory, there's a controlled maturing

warehouse, which is kept at a constant ten degrees Centigrade.

There are over 28,000 tonnes of cheese ripening at any one time,

worth over £150 million.

Is it only the expensive artisan cheese that is matured?

Absolutely not, all our cheese has to be matured.

When it comes from the production area, it's actually curd, and that

curd needs to be broken down into cheese particles that we can eat.

A standard cheddar will take around six months to mature,

but it's Colin's job to work out which cheese can ripen and

improve its flavour over the next 18 to 24 months, to become extra mature

and he wants to see if I can tell which cheese has that potential.

So what am I looking out for in the taste?

-You're looking for a nice clean flavour, buttery, smooth.

-Mmm.

And that makes it have the potential to mature into an extra mature.

OK, I've tried that one, it's delicious.

This one's three months older than the previous one.

That tastes a little more bitter. A little less creamy.

-Yeah.

-I mean, it's so subtle.

-And you're right.

-Really?

That was the poor one, the one that's not going to make the grade,

-so that one's going to be sold now.

-So I'd selected the correct one,

does that mean that I get a job here?

You get the job.

Tasting cheese all day. I am happy as Larry.

Back at the dairy factory,

the next vital stage for our milk is for it to be bottled.

40,000 plastic bottles an hour are blow-moulded in a process

so secret that it has to be kept from competitors,

so I'm not allowed to see it.

And there's no point making them somewhere else, you'd just be

transporting air, so they're made here in a factory on site.

A million bottles a day.

Once they're created, the empty bottles are transported

to the colossal filling hall.

It's the size of the pitch at Wembley Stadium,

containing six filling lines.

Brilliant! All of a sudden, it's got milk in it.

Up until now, milk has just been in vast volumes that I can't compute.

Now I can see a bottle that I buy.

And in this highly-automated world,

the only guy I can find here is Miles Lord, production team leader.

Do you know how fast this is going?

Well, this filler now is running at 17,000 bottles an hour.

Which is the same as 4.7 a second.

Nearly five bottles a second?

Nearly five bottles a second. There's three stages to the filling.

When it first comes in, it runs at a slower rate

and that stops it splashing up and foaming.

Then the speed increases, we put more in.

And the last bit, we slow that right down again

just so it doesn't foam at the top.

And that's how I pour my beer.

Exactly.

It's got to keep moving, hasn't it?

If we have the line standing for 20 minutes, we've got

to get rid of the milk that's on the line.

Just 23 hours and 56 minutes after leaving the cow,

I can watch our milk get bottled,

although it can take up to 48 hours to reach this point.

What's happening now?

We've filled the bottle up and within seconds,

within point-seconds, we put a cap on it.

I can't think of anything worse than milk dripping all over my shopping.

How can you guarantee that that lid is on?

Everything we do is checked at every stage

to make sure that the milk is fine.

We have a camera, it's looking at every single bottle that goes out

and it's saying, "Is that in the right place?"

And what happens if it's not?

If it's not, it'll reject it.

Can we put one on there isn't right and see what happens?

We can.

To test the camera, we've taken the foil seal off and replaced the lid.

So it should be spotting it.

MACHINE BEEPS GREGG CHEERS

There you go, that's our bottle.

Do you load it into these cartons of milk?

-We don't do that here, no.

-Good.

-Do you not like those?

-No, the whole nation hates them.

-OK, yeah.

-This is what we want.

You can open that and not end up with it over your jumper.

Yeah, absolutely, hopefully.

While I'm bowled over at the scale of bottled milk produced here,

Arla makes another product on a mammoth scale that gets

spread on our toast every morning.

The co-operative produces 43% of the UK's butter.

And Ruth is retracing the steps of Victorian dairy maids

to discover just how butter used to be made.

Before refrigeration, milk went sour very quickly,

so farmers had to come up with ways not to waste it.

The answer - turn it into butter.

But it was hard physical labour, and as it was considered indoor work,

mostly a job for dairy maids, many as young as 13.

A maid might have to milk as many as ten cows in the morning

before she could even start making the butter.

That's about two and a half hours' work before you've even begun.

On this working Victorian farm in Shropshire,

Ingrid Hartung keeps traditional techniques alive.

She chills milk in cool water to make the cream rise to the top

and skims it off to make butter.

So there it is, our lovely cream.

And then, of course, from this we make yellow butter.

That's right. In the spring/summer,

it is actually a nice yellow, rich colour because, of course,

the natural ingredients that the cows are eating when they're grazing

outside makes a nice yellow colour.

Although grass looks green, there's actually a yellow/orange

chemical called beta carotene found in every mouthful a cow eats.

In winter, when the cows eat less grass,

they produce a much paler butter

which is less appealing to consumers.

So here we are trying to do this in the middle of winter,

-which is, erm, challenging.

-Challenging, yes.

So dairy maids came up with an ingenious solution to produce

just the right shade of yellow.

We substitute the carotene that the cows would eat in the grass

with a good old-fashioned carrot.

Just put a little bit and see what colour.

Not very much but there we go, we don't want to overdo it.

We're now ready for the hard graft of making butter.

Now, if we've got everything absolutely perfect

and the cream's top quality and the temperatures are perfect,

we could expect this cream to turn in what? 20 minutes?

If it cools down a bit, half an hour, but something like that, yes.

The cream needs to be shaken enough

so that the fat in it clumps together to make butter.

And if we've got it all wrong we could be here...?

Two hours plus.

THEY LAUGH

We'll take turns. Go on, you get started.

'Unlike a lot of jobs for women at the time, dairy work was well paid,

'but you had to have very strong shoulders and arms.'

So shall I take over for a bit?

Yes, if you want to, that would be very good.

'Using a much larger churn, a really brawny dairy maid could

'make 20 or 30lb of butter in one go.'

So let's just have a little look.

'After churning until my arms ache, I'm starting to realise what

'a difficult job being a dairy maid would have been.

'17 pints of milk yields only a pound of butter.

'In my case, no butter at all.

'So far, it's just really thick cream.'

So we are hitting two and a half hours and it's still not come.

-Yeah.

-I mean, this can happen, can't it?

-Yeah.

If the weather's difficult and the cold...

Sometimes it's the cream,

but at this time of year, it's more likely to be the cold, yeah.

Despite butter being best kept in the fridge,

ideally it needs room temperature for the fats to solidify.

So here, in the freezing temperatures of the dairy,

we're having trouble.

It's very disappointing,

-but luckily you had got a batch you'd already done.

-Yes.

THEY LAUGH

Once the butter was formed, any dairy maid worth her salt

would shape a design as a trademark.

There are all kinds of different patterns that you can just do

with the butter pats.

That's a single wheat sheaf.

Hand-crafted butter became far less common after mechanisation

was gradually introduced during the 19th century.

Today, automatic churns have almost entirely replaced

the muscles of dairy maids.

But our love affair with creamy butter still continues.

Back at the dairy factory,

it's taken our milk just under 24 hours to get into a bottle.

Now the bottles are put onto trolleys

and are heading for distribution to our grocery shelf.

We've just packed up this milk the other side of that wall.

Traditionally, in this hall would have been hundreds of people,

but here they like to do things a little differently.

MUSIC: Robot Rock by Daft Punk

This is the only place in the UK

where futuristic robots like these distribute milk.

In this custom-built, enormous fridge

75 state-of-the-art robots transport all this from the filling zone

to the distribution bays

to send on to supermarkets nationwide.

They shift 1.5 million litres of milk per day,

enough to provide daily milk to Greater Manchester, Somerset

and the West Midlands combined.

I've never seen anything like this ever.

This looks nuts to me.

Dispatch team leader, Paul Ansell, is a robot expert.

Somebody is controlling these robots, are they?

I mean they're not thinking for themselves?

It's not a human that controls the robots, they're controlled

by the warehouse management system that's in the fridge.

When the milk comes through the door, there's an RFID,

a radio frequency identification number that goes to each trolley,

and then the robots will move or action their moves around the fridge.

With robots running backwards and forwards,

you must have to be careful where you stand.

Not really, it's got the sensor in front.

The laser's always looking in front of it at any given time.

I'm going to test out the robot's

laser beam collision avoidance device.

Whoa, whoa, whoa, whoa.

HE LAUGHS

That's just nuts.

You could actually take your robot for a walk.

Come on, come on. Come on, then.

Stop.

Good boy.

And off she goes.

After 35 miles of work

these robots know to automatically dock

and charge their lithium batteries.

It goes and puts its feet up and has a cup of tea.

It puts itself on charge.

If you didn't have the robots here, you'd need people.

How many people would you need?

Somewhere in the region of 300 people in this fridge alone.

I've been in this business 18 years now.

So, I started in a fridge, I effectively was a robot.

You have to think each trolley weighs about 240 kilos, if you're

doing that for a 12-hour shift, it's very, very labour intensive.

-So a robot never phones in sick.

-No.

-Never takes a tea break when he shouldn't be.

-No.

But you can't talk to a robot about football on a Monday.

You could try but you wouldn't get an answer back.

Robots haven't just taken control in this spectrum.

Out on the farms, there is a robotic revolution going on.

In the heart of the Lancashire countryside is a scene

that could be from science fiction.

On a dairy farm in Blackburn the cows are in control.

MUSIC: Thus Spake Zarathustra by Richard Strauss

This is a state-of-the-art Merlin.

An automatic, laser-guided, milking robot.

Machines like these are being used in about 5% of farms in the UK

and the cows can choose to use them whenever they want.

Chris Bargh installed his three milking robots six years ago.

His herd of 180 cows choose to milk themselves three times a day,

producing 5,000 litres.

-The cows come in when they want to be milked.

-Yeah.

-And they get milked by robots.

-Yes.

The cows actually come and milk themselves

whenever they want to be milked.

It's all robotic milking now. It's absolutely amazing.

That cow can't wait to get in.

Can't wait to get in, no.

So they're actually queuing up to get in there.

Yeah, no, they just come in and queue up whenever.

And the clever cows will look to see which has the shortest queue.

With the cow in position, it's time for the robot to get to work.

So you'll see now as the brushes come round...

and they go round and clean the teats.

Oh, my word.

And then you'll see the lasers start flashing on the teats now.

Oh, yeah. Yeah, yeah, yeah, yeah.

Yeah, so now it's pinpointing exactly where them teats are.

-Oh, it's going...

-Yeah, it's got it, it's got it.

These robots are working 24 hours a day.

They never stop, yeah.

-The cows can be milked whenever they want.

-Yes.

So the cows coming out now, anybody that's used the public transport

in London will recognise this, I think.

-You put your ticket in, the barrier moves.

-Yeah.

Now how does the robot know which cow it's got?

Every cow has a little ear tag - a little transponder in its ear -

and that's measured on the robot.

Chris' robots can record almost every aspect of his herd, from each

cow's exact diet, to the amount of fat, protein and sugar in the milk.

When I was a lad, I was still milking conventionally, that had to be sent

away to a laboratory once a month to be able to get that information.

Now, every single time that cow's milked,

we know that information.

Merlin needs to be strong enough to cope with the weight of a

full-size cow, which can be as heavy as 11 men,

but it also needs to be gentle enough for milking.

The robot can make tiny adjustments to the squeeze on the cow's teat

so it feels even gentler than a calf's mouth.

The first robots were introduced in the '90s,

but more recently the technology has advanced

and now about 30% of new milking systems in the UK are robotic.

But what happens if it goes wrong?

If the same fault happened with three cows on the trot,

the whole robot shuts itself down and rings my mobile phone

to tell me there's a breakdown.

And the use of technology goes way beyond milking.

It can even offer a calming back rub to keep the cows contented.

Aren't we missing out here on the human interaction between you,

the farmer, and the cow?

We see the character of these cows so much more now,

because we're not forcing 'em.

Because humans aren't really telling them to do anything.

Yeah. They're relaxed and chilled.

We've had the robots in six years now, and when we first put them in,

everyone was a little bit nervous. Oooh, robotic milking the cows.

Some of the older cows wouldn't change their ways.

80% of the herd have never seen a standard parlour,

they just assume that milking is done like this and always has been.

Mate, I love this. I absolutely love this.

Well, listen, I'm not a farmer, but they look pretty happy to me

and they're wandering in of their own accord, no doubt about that.

These cows want to be in there, they want to be milked.

-I can tell you that.

-Yes.

These are happy cows and the milk yields are up.

This could well be the future.

While Gregg has seen the future of milking,

I've come to a factory in Gloucester to see how milk is

turned into one of the most decadent products of all.

This tanker contains 28 tonnes of milk,

and at this factory they get through around six of them a week.

This factory is an ice cream lover's delight.

Brian Field is the quality assurance manager.

Why is milk so important to ice cream?

Milk is one of the fundamental ingredients

from which ice cream is made. All our ice cream recipes use milk.

We use whole milk, we use cream, we use concentrated milk

and we use milk powder.

Brian takes me to where it all starts, the mix department.

Whoa, oh, my goodness!

There's the ice cream mix.

That smells amazing.

We add our milk, our sugar and our water,

blend it all together to make the ice cream mix.

Once that's done, we add some vanilla essence.

'Each vat holds four tonnes of milk

'and normally needs 4kg of vanilla essence.'

-There we go.

-Perfect.

What will this become?

-This will become Magnum.

-Really?

-Yeah.

-So this will contribute...

-This is the centre of Magnum.

This is my greatest dream,

I can't believe I'm at the centre of an ice cream.

Once the ingredients are combined, they're pasteurised

and then the mix makes its way to the factory floors.

Greg Barrett is the production labour manager.

From the mix department, the mix is pumped over to these freezers.

-Yes.

-And in these freezers

it's almost whisked like an egg to minus-six.

At this point, a vital ingredient is added - air -

which, believe it or not, makes up half of ice cream.

And the more air, the softer the ice cream.

As you can see there, the stick is put in it.

An ice cream at minus-six degrees is quite pliable.

Oh, wow.

As you can see by that.

So it's still very soft at this stage.

Yes, we've got to get it quickly hardened into a hardening tunnel.

It then comes out the other side and it's that hard it's almost brittle.

In this hardening tunnel the ice creams are blast frozen.

This ultra-fast freezing creates tiny ice crystals in the mix.

The smaller the crystals,

the smoother the texture of the ice cream.

And as you can tell, it's very, very brittle.

-I mean, it's rock hard.

-Rock hard, yeah.

Absolutely rock hard.

Now we dip it in the chocolate.

But if the chocolate is hot, I presume ...

Yes, it's plus-44 degrees.

Then when you dip that in, surely the ice cream will melt.

No, it won't melt because it's been in the hardening tunnel

for half an hour approximately, at minus-40 degrees.

And now the ultimate ice cream experience,

the frozen vanilla ice cream is coated in warm Belgian chocolate.

MUSIC: L'amour Est Un Oiseau Rebelle by Georges Bizet

That may be the most beautiful thing I've ever seen.

That is pure decadence.

Absolutely amazing.

The chocolate-coated ice creams are wrapped, boxed and packed,

ready for cold storage and distribution.

To fulfil our boundless love of ice cream

this factory runs 24/7,

making 10 million Magnums and 5 million Cornettos a week,

as well as many other lines,

producing over 1.4 billion pieces of ice cream every year.

Not bad when you think the core ingredient is milk.

At the dairy factory distribution hall, there is good news.

Robots haven't taken over completely

and dispatch manager Mark Burrows is showing me why.

If the customer is ordering anything other than a full trolley,

we then have to pick that by hand.

-So let's say there's a 100 in there.

-Yes.

If the supermarket orders 103, we have to pick up three.

We do, yeah. Slip those over your ears.

I might have spoken too soon.

Put this round your waist.

It looks like computers are in control after all...

'Talk now, say "ready".'

..as they're giving the orders.

Just give it the command "ready".

-Ready.

-'Scan destination'

Scan destination.

So you need to scan the RFID tag.

You'll hear it vibrate,

so it knows exactly what product's on that trolley now.

'Material description - Asda four pint semi.'

-Asda four pint semi.

-'Pick 60.'

Pick 60. Oh, crying out loud.

Right, so I need 60 of those.

This is hard work.

After my brief training,

I am responsible for getting the Weston-Super-Mare order right.

'Material description - Cravendale two litres.'

Cravendale two litre. Four.

'Material description - organic semi.'

Ready.

-Two pints.

-'Pick 20.'

I'm stuck.

The milk I've just collected needs help to get to the loading bay.

Juliet Echo Bravo.

'Juliet Echo Bravo.'

-Is that our robot?

-That's our robot, yeah.

Off to Weston-Super-Mare.

Off to Weston-Super-Mare.

Somebody's going to get our milk tomorrow morning.

The milk I've just hand-picked is about to be

one of the 400 deliveries made every day.

This is the last stage, it's on its way to Weston-Super-Mare.

It's going to be on someone's breakfast cereal tomorrow morning.

Come on, boys.

I have regularly walked into a shop

and just grabbed a bottle of milk, whether it be the corner shop or

the supermarket, I've never thought about where it comes from. I just

take it for granted it's going to be there and it's going to be safe.

I've followed the milk now all the way from the cow,

all the way through every single process,

through all the testing, the bottling, the unbelievable

amount of people and technology that goes in to making it

possible for me and you to grab a bottle of milk whenever we want.

Incredible story.