Four decades have passed since the first McDonald’s opened in Woolwich, South London

Next week marks a very significant date in British gastronomical history: it’s the 40th anniversary of the day we fell in love with fast food.

Four decades have passed since the first McDonald’s opened in Woolwich, South London.

It was quite an event - the mayor cut the ribbon and hundreds queued around the block to get a taste of the American culinary dream.

But as with most love stories, the relationship between the British and McDonald’s hasn’t always run smoothly.

Having been hit in the late Nineties by the outbreak of mad cow disease, public sentiment in Britain also turned against the chain by the long-running, so-called ‘McLibel’ trial.

The company spent £10 million suing the activists Dave Morris and Helen Steel for what it said were defamatory claims made in leaflets the couple produced about McDonald’s and its business practices.

While it ended with the chain being awarded damages, critical comments in the judge’s ruling, and the David-and-Goliath nature of the legal battle meant it was a PR disaster for the U.S. corporation.

There was more bad publicity with Super Size Me — Morgan Spurlock’s 2004 film that documented the drastic effect an exclusively McDonald’s diet had on his physical and psychological wellbeing.

More recently, a particularly unappetising photograph of a frozen McRib, a menu item popular in North America, went viral. It looked less like meat, and more like a piece of industrial foam insulation.

Faced with falling international sales, last month the company launched an online campaign to counter a range of McDonald’s ‘myths’.

As part of this new openness, they admitted that for seven years until 2011, McDonald’s in the U.S. used so-called ‘pink slime’ to bulk out its burgers.

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The slime was made from pieces of flesh scraped from animal carcasses, spun around in a centrifuge, treated with ammonia to kill off salmonella and e-coli and then compressed together.

While such ingredients were never used in this country, where sales have remained relatively strong, a quick glance at the company’s own question-and-answer website here shows British consumers clearly have their doubts about what they are being served.

‘Is it true that Chicken McNuggets include the beak?’, asks one. Another posts: ‘Are McDonald’s milkshakes made with pork fat?’

So when, last week, I was invited along to witness first-hand how the company’s most iconic and popular of offerings - the Big Mac - travels from field to carton, it was an offer I simply could not refuse.

Destined for dinner: Tom Rawstorne is pictured with Robert Knight's herd of cattle

As a 43-year-old father of three daughters living in the Kent countryside, my opportunities to sample McDonald’s fare are surprisingly few and far between.

My wife Charlotte, survives on a diet of mainly rye bread and juiced kale, while the older two — aged nine and 12 —would rather have a tuna baguette at Pret a Manger than a Happy Meal.

The youngest, aged four, is a more willing visitor — if only to get her hands on the latest promotional toy — but she is easily outvoted when it comes to family outings.

As a result, I’m lucky to eat more than one Big Mac in a year.

My journey began deep in the Northamptonshire countryside, where I stand in a barn full of cattle with farmer Robert Knight.

He is the third generation to work this 2,000 acre farm and clearly takes great pride in the 300-odd calves he breeds here every year.

‘Don’t you think they look contented?’ he asks me, as we pause in front of a stall of 20 cud-chewing bovines.

As much as a cow can look happy, these certainly do.

Mainly born in the spring, they’re a mixture of breeds, and are fattened up for between 16 and 24 months before being sent to slaughter.

Summers are be spent outside on pasture, winters indoors being fed a diet of silage and rolled wheat and barley.

How does he feel about the product of his hard work ending up in a fast-food restaurant? Given the phalanx of McDonald’s minders accompanying me on the tour of the farm, shadowing my every move, I’m not expecting a controversial answer.

Daily Mail feature writer Tom Rawstorne is pictured at the OSI meat facility in Scunthorpe

‘I haven’t been to McDonald’s for some years, but only because my children are older now,’ the 51-year-old says. ‘But I think McDonald’s is sourcing meat from people like me for all the right reasons.’

The primary reason is that he is a British farmer and here in the UK McDonald’s only uses meat reared in Britain or Ireland - its policy for the past 14 years.

Robert doesn’t sell direct to McDonald’s. He is one of 16,000 British and Irish farmers who supply abattoirs who in turn supply the one factory in this country that makes McDonald’s burgers.

Every month a lorry pick up 16 calves from the farm and delivers them to an abattoir at Cardington, in Bedfordshire.

It’s run by Dawn Meats, a company that has had a contract to supply the McDonald’s burger factory for the past 20 years.

Sarah Haire is the abattoir’s agriculture manager and explains in a no-nonsense way how the cattle will be killed.

‘A vet will examine them to see if they are fit for slaughter, after which they will be moved into a stall and stunned with a captive bolt,’ she says.

Last year the Scunthorpe plant processed some 34,000 tonnes of beef - the meat from some 440,000 head of cattle

‘They will roll out, be shackled and then hoisted into the air and their throats cut. That is what will kill them.’

‘They are bled for three minutes and their hide, head, feet and guts come out, the spinal cord is removed and the meat is inspected by the hygiene inspector.’

(This does not make them halal, it’s just deemed the most efficient and humane way to slaughter them. )

‘Each day 300 cattle go through the abattoir,’ she says.

What McDonald’s want for their burgers is the forequarter and flank - basically the front half of the animal. The rear end (home of the sirloin and T-bone steaks) will go to other clients, such as Marks & Spencer, explains Sarah.

That’s all well and good, but has all the beef that ends up in a McDonald’s burger lived as idyllic a life as those on Robert’s farm?

What, I ask, about claims that McDonald’s also uses the meat from old, spent dairy cows? This prompts a noticeable cloud to descend on proceedings.

The McDonald’s representatives don’t like me using the world ‘old’ and insist they are not looking for any particular type of cow, just for one that produces meat that matches their ‘quality specification’.

Sarah from the abattoir even says that ‘just because a cow has done another job in another life it should not be discriminated against’.

I push on, and ask what proportion of the meat does come from ex-dairy cows. I’m told that it makes up some 20 per cent of the total amount used.

Given how many cows go into making McDonald’s burgers that’s no small number, something that is rammed home to me when I arrive at the football-pitch-sized burger factory in Scunthorpe.

Founded in Chicago, the company that operates it - OSI - first began supplying McDonald’s in the U.S, in the Fifties, and followed the restaurant round the world as it expanded.

Last year the Scunthorpe plant processed some 34,000 tonnes of beef - the meat from some 440,000 head of cattle.

The plant employs 170 staff on two eight-hour shifts, turning out up to 3 million burgers a day

It employs 170 staff on two eight-hour shifts, turning out up to 3 million burgers a day.

Having signed a disclaimer to confirm I’m not afflicted by vomiting or diarrhoea or suffering from ‘discharge from the ears’, I’m made to remove my wedding ring, dress in white overalls, don a hair net and helmet, and thoroughly disinfect my hands, before I can step inside.

Walking inside, I’m struck by the cold, and by the size of the operation - dozens of huge, industrial wheelie-bin sized containers hold the beef, cut into caveman-sized joints, deep red in colour with coatings of white fat.

My initial reaction to the sight of all this raw meat is an urge to throw up my (meat-free) breakfast - something that given the factory’s obsession with health and safety would doubtless close the plant and cause a nationwide shortage of Big Macs.

But I steel myself and, thanks to a surprising lack of smell and an absence of blood, manage to watch as the slabs of beef are tipped into the first enormous mincing machine.

At the push of a button, chunks as big as a man’s thigh are almost instantly ground into a coarse mince, the strands 11mm (less than half an inch) in diameter. At this stage fat content is measured. It should be at 20 per cent. If it’s not leaner or more fatty meat is added to hit the target.

Interestingly, it is also at this stage that minced, frozen meat is added to the mix.

While the meat’s origins are identical, being frozen lowers the overall temperature of the mince, so it will hold together better when formed into patties.

Cooking and assembly of a Big Mac should take 90 seconds

Without it, some sort of binder would have to be used.

McDonald’s admits it is possible that any one burger could contain meat from more than 100 animals.

Grinding in a second machine produces a much finer 2.4mm mince - pink and gloopy - which is then fed into the pressing machine that will form the individual burgers. It fires out burger-shaped discs of meat at a rate of 516 patties a minute.

Squeezed out on to a conveyor belt, the next stop on the burger’s journey will take it through a cryogenic freezing tunnel from which it will emerge, a minute later, frozen solid at minus 20C.

The burgers are packed 300 to a box and palleted up for refrigerated storage. The whole process from lump of meat to frozen burger takes less than half an hour. Surprisingly straight-forward — but nothing is left to chance.

Then I am shown into a laboratory where every 30 minutes, white-coated quality assurance experts measure the burgers’ vital statistics.

The Big Mac patty should measure between 95mm and 100mm (just under four inches) across, be between 6.8mm and 7.5mm (a quarter inch) thick and weigh 44.4g to 45.5g (1.6oz)

Not only should they all look the same, they should taste the same too. To this end, in a corner of the lab they have exactly the same grill as is to be found in a real McDonald’s kitchen.

There they cook the burgers then mark them for bite, texture, greasiness and just about anything else you can think of. Five times a year samples are sent to Munich, the quality control headquarters, to compare with other burgers from other European suppliers. No one is looking to win this competition — just to be the same.

Back in Scunthorpe I ask Tracy Brown, a tester for nine years, how she enjoys the job. ‘Put it this way,’ she jokes, ‘I don’t really need dinner after a day here.’

I’m invited to taste a cooked burger, and struggle to raise much enthusiasm for it — without its normal accompaniments it’s predictably bland.

Hoping for better things, I head to Dalby on the edge of Doncaster where I have a crash course in serving the perfect Big Mac in a real McDonald’s restaurant.

As with the rest of the process, the cooking is forensically standardised: the three buns — crown (the top), club (the bread between the two burgers that make a Big Mac) and heel (the bottom) — are toasted for exactly 35 seconds.

The bottom and middle buns are garnished with a precisely measured squirt of yellow ‘special sauce’, 7g of very finely chopped onion, 24g of lettuce, a slice of yellow cheese and precisely two slices of pickle.

Staff are pictured working in the kitchen of McDonald's restaurant in Woolwich, South London in 1974

Then come the patties: cooked for exactly 42 seconds, clamped between two jaws of a grill — the top heated to 218C, the bottom to 177C (the exact, standardised combination of temperatures, no doubt arrived at after years of experimentation).

Once cooked, the burgers are garnished with a single shake of salt and pepper, placed on top of the bottom two patties, and topped with a toasted crown.

Cooking and assembly should take 90 seconds. Mine takes at least five minutes. I burn two lots of buns, am told the distribution of my lettuce is not ‘gold standard’, and personalising it with an extra slice of pickle (the best part of a Big Mac, I always think) raises an eyebrow or two.

Customers, who consume 90 million Big Macs in a year, see none of this.

What they have demanded - and what McDonald’s has delivered - is a burger that tastes like the burger that they tasted last week, last year or, indeed, in 1974.

Only time will tell whether today’s younger customers - more discerning, and demanding more choice - will feel the same way about the Big Mac in the years to come.

So what about the finished product? As I bite into my hand-crafted effort I have to say I feel reassured, not concerned, by what I have seen.

The process is surprisingly simple - then again, so is the end product.