Think you eat only healthy, unprocessed foods? Think again. Joanna Blythman went undercover and discovered that even your fruit salad is not what it seems

On a bright, cold day in late November 2013, I found myself in the dark, eerie, indoor expanses of Frankfurt’s Blade Runner-like Festhalle Messe. I was there undercover, to attend an annual trade show called Food Ingredients. This three-day exhibition hosts the world’s most important gathering of ingredients suppliers, distributors and buyers. In 2011, when it was held in Paris, more than 23,000 visitors attended from 154 countries, collectively representing a buying power of €4bn (£2.97bn). Think of it as the food manufacturers’ equivalent of an arms fair. It is not open to the public. Anyone who tries to register has to show that they work in food manufacturing; I used a fake ID.

While exhibitors at most food exhibitions are often keen for you to taste their products, few standholders here had anything instantly edible to offer. Those that did weren’t all that they seemed. Canapé-style cubes of white cheese dusted with herbs and spices sat under a bistro-style blackboard that nonchalantly read “Feta, with Glucono-Delta-Lactone” (a “cyclic ester of gluconic acid” that prolongs shelf life).

A pastry chef in gleaming whites rounded off his live demonstration by offering sample petits fours to the buyers who had gathered. His dainty heart- and diamond-shaped cakes were dead ringers for those neat layers of sponge, glossy fruit jelly, cream and chocolate you see in the windows of upmarket patisseries, but were made entirely without eggs, butter or cream, thanks to the substitution of potato protein isolate. This revolutionary ingredient provides the “volume, texture, stability and mouthfeel” we look for in cakes baked with traditional ingredients – and it just happens to be cheaper.

This is the goal of the wares on show, something the marketing messages make clear. The strapline for a product called Butter Buds®, described by its makers as “an enzyme-modified encapsulated butter flavour that has as much as 400 times the flavour intensity of butter”, sums it up in six words: “When technology meets nature, you save.”

Exhibitors’ stands were arranged like art installations. Gleaming glass shelves were back-lit to show off a rainbow of super-sized phials of liquids so bright with colouring, they might be neon. Plates of various powders, shaped into pyramids, were stacked on elegant Perspex stands bearing enigmatic labels – “texturised soy protein: minced ham colour,” read one.

While I never knowingly eat food with ingredients I don’t recognise, I'd probably consumed many ‘wonder products'

Manufacturers who need their tomato sauce to be thick enough not to leak out of its plastic carton – and just a little bit glossy, so that it doesn’t look matt and old after several days in the fridge – were sold the advantages of Microlys®, a “cost-effective” speciality starch that gives “shiny, smooth surface and high viscosity”, or Pulpiz™, Tate & Lyle’s tomato “pulp extender”. Based on modified starch, it gives the same pulpy visual appeal as an all-tomato sauce, while using 25% less tomato paste.

The broad business portfolio of the companies exhibiting at Food Ingredients was disconcerting. Omya, based in Hamburg, described itself as “a leading global chemical distributor and producer of industrial minerals”, supplying markets in food, pet food, oleochemicals, cosmetics, detergents, cleaners, papers, adhesives, construction, plastics and industrial chemicals. At Frankfurt, Omya was selling granular onion powder, monosodium glutamate and phosphoric acid. For big companies such as this, food processing is just another revenue stream. They experience no cognitive dissonance in providing components not only for your meal, but also for your fly spray, scratch-resistant car coating, paint or glue. The conference was the domain of people whose natural environment is the laboratory and the factory, not the kitchen, the farm or the field; people who share the assumption that everything nature can do, man can do so much better, and more profitably.

Tired after hours of walking round the fair, and, uncharacteristically, not feeling hungry, I sought refuge at a stand displaying cut-up fruits and vegetables; it felt good to see something natural, something instantly recognisable as food. But why did the fruit have dates, several weeks past, beside them? A salesman for Agricoat told me that they had been dipped in one of its solutions, NatureSeal, which, because it contains citric acid along with other unnamed ingredients, adds 21 days to their shelf life. Treated in this way, carrots don’t develop that telltale white that makes them look old, cut apples don’t turn brown, pears don’t become translucent, melons don’t ooze and kiwis don’t collapse into a jellied mush; a dip in NatureSeal leaves salads “appearing fresh and natural”.

For the salesman, this preparation was a technical triumph, a boon to caterers who would otherwise waste unsold food. There was a further benefit: NatureSeal is classed as a processing aid, not an ingredient, so there’s no need to declare it on the label, no obligation to tell consumers that their “fresh” fruit salad is weeks old.

Somehow, I couldn’t share the salesman’s enthusiasm. Had I eaten “fresh” fruit salads treated in this way? Maybe I had bought a tub on a station platform or at a hotel buffet breakfast? It dawned on me that, while I never knowingly eat food with ingredients I don’t recognise, I had probably consumed many of the “wonder products” on show here. Over recent years, they have been introduced slowly and artfully into foods that many of us eat every day – in canteens, cafeterias, pubs, hotels, restaurants and takeaways.

Facebook Twitter Pinterest Food engineers can now create a ‘natural’ mature cheese flavouring within 72 hours. Photograph: Franck Allais/The Guardian

You might find it all too easy to resist the lure of a turkey drummer, a ready meal, a “fruit” drink or a pappy loaf of standard white bread. You might check labels for E numbers and strange-sounding ingredients, boycotting the most obvious forms of processed food. And yet you will still find it hard to avoid the 6,000 food additives – flavourings, glazing agents, improvers, bleaching agents and more – that are routinely employed behind the scenes of contemporary food manufacture. That upmarket cured ham and salami, that “artisan” sourdough loaf, that “traditional” extra-mature cheddar, those luxurious Belgian chocolates, those speciality coffees and miraculous probiotic drinks, those apparently inoffensive bottles of cooking oil: many have had a more intimate relationship with food manufacturing than we appreciate.

When you try to dig deeper, you hit a wall of secrecy. For at least the past decade, the big manufacturing companies have kept a low profile, hiding behind the creed of commercial confidentiality, claiming they can’t reveal their recipes because of competition. Instead, they leave it to retailers to field any searching questions from journalists or consumers. In turn, retailers drown you in superfluous, mainly irrelevant material. The most persistent inquirers may be treated to an off-the-peg customer reply from corporate HQ, a bland, non-specific reassurance such as, “Every ingredient in this product conforms to quality assurance standards, EU regulations, additional protocols based on the tightest international requirements, and our own demanding specification standards.”

My growing preoccupation was how little we know about the food that sits on our supermarket shelves, in boxes, cartons

I spent years knocking on closed doors, and became frustrated by how little I knew about contemporary food production. What happens on the farm and out in the fields is passably well-policed and transparent. Abattoirs undergo regular inspections, including from the occasional undercover reporter from a vigilante animal welfare group, armed with a video camera. My growing preoccupation was instead just how little we really know about the food that sits on our supermarket shelves, in boxes, cartons and bottles – food that has had something done to it to make it more convenient and ready to eat.

Eventually, contacts within the industry provided me with a cover that allowed me to gain unprecedented access to manufacturing facilities, as well as to subscriber-only areas of company sites, private spaces where the chemical industry tells manufacturers how our food can be engineered. Even with 25 years of food chain investigations under my belt, it was an eye-opener.

Anything that comes in a box, tin, bag, carton or bottle has to bear a label listing its contents, and many of us have become experts at reading these labels. But many of the additives and ingredients that once jumped out as fake and unfathomable have quietly disappeared. Does this mean that their contents have improved? In some cases, yes, but there is an alternative explanation. Over the past few years, the food industry has embarked on an operation it dubs “clean label”, with the goal of removing the most glaring industrial ingredients and additives, replacing them with substitutes that sound altogether more benign. Some companies have reformulated their products in a genuine, wholehearted way, replacing ingredients with substitutes that are less problematic. Others, unconvinced that they can pass the cost on to retailers and consumers, have turned to a novel range of cheaper substances that allow them to present a scrubbed and rosy face to the public.

Imagine you are standing in the supermarket. Maybe you usually buy some cured meat for an antipasti. Picking up a salami, even the most guarded shopper might relax when they see rosemary extract on the ingredients list – but rosemary extracts are actually “clean-label” substitutes for the old guard of techie-sounding antioxidants (E300-21), such as butylhydroxyanisole (BHA) and butylhydroxytoluene (BHT). Food manufacturers use them to slow down the rate at which foods go rancid, so extending their shelf life.

Rosemary extracts don’t always have to carry an E number (E392), but the more poetic addition of “extract of rosemary” makes it sound like a lovingly made ingredient – especially if that salami is also labelled as natural or organic. And the extract does have something to do with the herb, usually in its dried form. The herb’s antioxidant chemicals are isolated in an extraction procedure that “deodorises” them, removing any rosemary taste and smell. Extraction is done by using either carbon dioxide or chemical solvents – hexane (derived from the fractional distillation of petroleum), ethanol and acetone. Neutral-tasting rosemary extract is then sold to manufacturers, usually in the form of a brownish powder. Its connection with the freshly cut, green and pungent herb we know and love is fairly remote.

Not sure what to have for dinner? How about a chicken noodle dish? If you noticed that it contained an amino acid such as L-cysteine E910, your enthusiasm might wane, especially if you happen to know that this additive can be derived from animal and human hair. But a range of new-wave yeast extracts is increasingly replacing E910. One supplier markets its wares as “a variety of pre-composed, ready-to-use products that provide the same intensity as our classical process flavours but are labelled as all-natural. Ingredients are available in chicken and beef flavour, with roasted or boiled varieties, as well as white meat and dark roast.” All can be labelled as “yeast extract” – a boon for manufacturers, because yeast extracts have a healthy image as a rich source of B vitamins. Less well known is the fact that yeast extract has a high concentration of the amino acid glutamate, from which monosodium glutamate – better known as MSG, one of the most shunned additives – is derived.

What else is in your basket? Suppose you are eyeing up a pot of something temptingly called a “chocolate cream dessert”. You read the ingredients: whole milk, sugar (well, there had to be some), cream, cocoa powder and dark chocolate. It all sounds quite upmarket, but then your urge to buy falters as you notice three feel-bad ingredients.

Facebook Twitter Pinterest This is the domain of people whose natural environment is the laboratory, not the kitchen; people who share the assumption that everything nature can do, man can do so much better and more profitably. Photograph: Franck Allais/The Guardian

The first is carrageenan (E407), a setting agent derived from seaweed that has been linked with ulcers and gastrointestinal cancer. It is now regarded in food industry circles as an “ideally not” (to be included) additive. The second of these worrying ingredients is a modified starch (E1422), or to give it its full chemical name, acetylated distarch adipate. It started off as a simple starch, but has been chemically altered to increase its water-holding capacity and tolerance for the extreme temperatures and physical pressures of industrial-scale processing. The third problematic ingredient is gelatine. This is anathema to observant Muslims, Jews and vegetarians, and even secular omnivores may be wondering what this by-product of pig skin is doing in their pudding.

Fortunately for the manufacturers of your chocolate cream dessert, there is a Plan B. They can remove all three offending items, and replace them with a more sophisticated type of “functional flour”, hydrothermally extracted from cereals, that will do the same job, but without the need for E numbers.

Another possibility for cleaning up this dessert would be to use a “co-texturiser”, something that would cost-effectively deliver the necessary thick and creamy indulgence factor. Texturisers, just like modified starches, are based on highly processed, altered starch designed to withstand high-pressure manufacturing – but because they are obligingly classified by food regulators as a “functional native starch”, they can be labelled simply as “starch”. Again, no E numbers. So, out come two additives and one ingredient that many people avoid, to be replaced by a single new-generation ingredient, one that is opaque in its formulation (proprietary secrets and all that) but which won’t trigger consumer alarm.

The history of food processing is littered with ingredients that were initially presented as safer and more desirable, yet subsequently outed as the opposite. Hydrogenated vegetable oils, or margarine, were actively promoted as healthier than the natural saturated fats in butter. High fructose corn syrup, once marketed as preferable to sugar, has now been identified as a key driver of the obesity epidemic in the US.

Is the clean-label campaign a heart-and-soul effort by manufacturers to respond to our desire for more wholesome food? Or just a self-interested substitution exercise? The lines are deliberately blurred: as one executive in a leading supply company put it, “Ingredients that give the impression that they originated in a grandmother’s kitchen and have not been processed too harshly are of great appeal to consumers.” Meanwhile, there is no evidence that manufacturers are using greater quantities of the real, natural ingredients consumers want. Clean labelling looks less like a thorough spring clean of factory food than a superficial tidy-up, with the most embarrassing mess stuffed in the cupboard behind a firmly shut door – where, hopefully, no one will notice.

From water-injected poultry and powdered coagulated egg, to ultra-adhesive batters and pre-mixed marinades, the raw materials in industrial food manufacturing are rarely straightforward. In fact, they commonly share quite complicated back stories of processing and intervention that their labels don’t reveal.

In the same way that you will never see a stray onion skin lying around a ready-meals factory, you’re extremely unlikely to see an eggshell, either. Eggs are supplied to food manufacturers in powders, with added sugar, for instance, or as albumen-only special “high gel” products for whipping. Liquid eggs will be pasteurised, yolk only, whites only, frozen or chilled, or with “extended shelf life” (one month) – whichever is easiest. They may be liquid, concentrated, dried, crystallised, frozen, quick frozen or coagulated. Manufacturers can also buy in handy pre-cooked, ready-shelled eggs for manufacturing products such as Scotch eggs and egg mayonnaise, or eggs pre-formed into 300g cylinders or tubes, so that each egg slice is identical and there are no rounded ends.

These hard-boiled, tubular eggs are snapped up by sandwich-making companies. Manufacturers can also take their pick from bespoke egg mixes, which are ready to use in everything from quiches and croissants to glossy golden pastry glazes and voluminous meringues. And there is always the cheaper option of using “egg replacers” made from fractionated whey proteins (from milk). No hurry to use them up: they have a shelf life of 18 months.

Facebook Twitter Pinterest The food industry has embarked on ‘operation clean label’ – removing the most glaring industrial ingredients and replacing them with substitutes that sound natural and benign. Photograph: Franck Allais

Food engineers can now create a “natural” mature cheese flavouring by blending young, immature cheese with enzymes (lipases or proteases) that intensify the cheese flavour until it reaches “maturity” – within 24 to 72 hours. This mature cheese flavouring is then heat-treated to halt enzymatic activity. Hey, presto: mature-tasting cheese in days rather than months. (Traditional cheddar is not considered truly mature until it has spent between nine and 24 months in the maturing room.)

A factory pantry looks nothing like yours. When the home cook decides to make a Bakewell tart, she or he puts together a lineup of familiar ingredients: raspberry jam, flour, butter, whole eggs, almonds, butter and sugar. The factory food technologist, on the other hand, approaches the tart from a totally different angle: what alternative ingredients can we use to create a Bakewell tart-style product, while replacing or reducing expensive ingredients – those costly nuts, butter and berries? How can we cut the amount of butter, yet boost that buttery flavour, while disguising the addition of cheaper fats? What sweeteners can we add to lower the tart’s blatant sugar content and justify a “reduced calorie” label? How many times can we reuse the pastry left over from each production run in subsequent ones? What antioxidants could we throw into the mix to prolong the tart’s shelf life? Which enzyme would keep the almond sponge layer moist for longer? Might we use a long-life raspberry purée and gel mixture instead of conventional jam? What about coating the almond sponge layer with an invisible edible film that would keep the almonds crunchy for weeks? Could we substitute some starch for a proportion of the flour to give a more voluminously risen result? And so on.

We all eat prepared foods made using state-of-the-art technology. And we don’t know what this diet might be doing to us

We all eat prepared foods made using state-of-the-art technology, mostly unwittingly, either because the ingredients don’t have to be listed on the label, or because weasel words such as “flour” and “protein”, peppered with liberal use of the adjective “natural”, disguise their production method. And we don’t know what this novel diet might be doing to us.

A disturbing 60% of the UK population is overweight; a quarter of us are obese. Are we leaping to an unjustified conclusion when we lay a significant part of the blame for obesity, chronic disease and the dramatic rise in reported food allergies at the door of processed food? There are several grounds for examining this connection.

Food manufacturers combine ingredients that do not occur in natural food, notably the trilogy of sugar, processed fat and salt, in their most quickly digested, highly refined, nutrient-depleted forms. The official line – that the chemicals involved pose no risk to human health when ingested in small quantities – is scarcely reassuring. Safe limits for consumption of these agents are based on statistical assumptions, often provided by companies who make the additives.

Manufactured foods often contain chemicals with known toxic properties – although, again, we are reassured that, at low levels, this is not a cause for concern. This comforting conclusion is the foundation of modern toxicology, and is drawn from the 16th-century Swiss physician, Paracelsus, whose theory “the dose makes the poison” (ie, a small amount of a poison does you no harm) is still the dogma of contemporary chemical testing. But when Paracelsus sat down to eat, his diet wasn’t composed of takeaways and supermarket reheats; he didn’t quench his thirst with canned soft drinks. Nor was he exposed to synthetic chemicals as we are now, in traffic fumes, in pesticides, in furnishings and much more. Real world levels of exposure to toxic chemicals are not what they were during the Renaissance. The processed food industry has an ignoble history of actively defending its use of controversial ingredients long after well-documented, subsequently validated, suspicions have been aired.

The precautionary principle doesn’t seem to figure prominently in the industry’s calculations, nor – such is their lobbying power – does it loom large in the deliberations of food regulators. If it did, then steering clear of manufactured products would be a lot easier.

The pace of food engineering innovation means that more complex creations with ever more opaque modes of production are streaming on to the market every day. Just last month, a dossier for a new line of dairy proteins dropped into my mailbox. Alongside a photo of a rustic-looking, golden pan loaf, the explanation read: “Many bakers are now turning to permeates, a rather new ingredient in the food ingredients market. Permeate is a co-product of the production of whey protein concentrate (WPC), whey protein isolate (WPI), ultrafiltered milk, milk protein concentrate (MPC), or milk protein isolate (MPI).”

Permeate, apparently, “contributes to the browning of baked goods” and produces bread that “retains its softness for a longer period of time and extends shelf life”. How clever. But I would prefer that my bread was browned solely from the application of heat. I’m prepared to accept that it will stale over time, rather than eat something that owes its existence to ingredients and technologies to which I am not privy, cannot interrogate and so can never truly understand. Am I about to hand over all control of bread, or anything else I eat, to the chemical industry’s food engineers? Not without a fight.

What your food label really means

Added vitamins One-dimensional factory versions of natural vitamins found in whole foods: ascorbic acid (man-made vitamin C) is usually synthesised from the fermentation of GM corn, while artificial vitamin E is commonly derived from petrol.

Soluble fibre A healthier-sounding term for modified starch, which is widely used to reduce the quantity of more nutritious ingredients in processed foods, and keep down manufacturers’ costs.

‘Natural’ colourings The only difference between these and artificial ones is that they start with pigments that occur in nature. Otherwise, they are made using the same highly chemical industrial processes, including extraction using harsh solvents.

Artificial ‘diet” sweeteners Several large-scale studies have found a correlation between artificial sweetener consumption and weight gain. Accumulating evidence suggests that they may also increase our risk of Type 2 diabetes.

Enzymes Used to make bread stay soft longer; injected into low-value livestock before slaughter, to tenderise their meat; and used in fruit juice processing to create a cloudier, more natural appearance.

‘Packaged in a protective atmosphere’ Food that has been “gassed” in modified air to extend its shelf life. It delays what food manufacturers call “warmed over flavour”, an off-taste that occurs in factory food.

Beef/pork/poultry protein Collagen extracted from butchered carcasses, processed into a powder and added to low-grade meats. It adds bounce, increases the protein content on the nutrition label and, combined with water, is a substitute for meat.

Washed and ready-to-eat salads “Cleaned” by sloshing around in tap water dosed with chlorine, often with powdered or liquid fruit acids to inhibit bacterial growth. The same tank of treated water is often used for 8 hours at a time.

‘Pure’ vegetable oil Industrially refined, bleached, deodorised oils. Food processors often add chemicals to extend their “fry life”.

‘Natural’ flavourings Even the flavour industry concedes that “there isn’t much difference in the chemical compositions of natural and artificial flavourings”. They are made using the same physical, enzymatic, and microbiological processes.

• This is an edited extract from Swallow This: Serving Up The Food Industry’s Darkest Secrets, by Joanna Blythman; published next week by 4th Estate, at £14.99. To buy a copy for £11.99, go to bookshop.theguardian.com or call 0330 333 6846.

Joanna Blythman will be doing a live online Q&A on Thursday 26 February – go here to join in.