In a corner of the labyrinthine European Union website (though offered in a mere 12 languages as opposed to the official 23) lurks a page of sprightly optimism. "Quality products catch the eye," reads the English version. Then comes a drum-roll colon, followed by nine sonorous initials: "PDO, PGI and TSG". I recently mentioned these acronyms to a dozen shoppers in London's Oxford Street. Not a single eye, sadly for Brussels, had been caught.

I tried asking the same respondents if they had heard of Champagne. All had. And when I asked them all when they last drank real Champagne, ten of the twelve knew what I meant (including one non-drinker). Nine had heard of Gorgonzola, and seven of Arbroath Smokies. And then, mystified by the smiling stranger's apparently random questions, they went on their way.

It's not a bad result. The acronym-hungry can find out exactly what those nine letters signify in the box below/overleaf; they are commonly called (in English as well as French) 'appellations'. An appellation is a name; use of this noun implies legal protection of that name. Hence my trick question about 'real Champagne'. For many English-speakers, Champagne is simply a synonym for sparkling wine. Indeed in the USA, it remains legal to label sparkling wine 'champagne', rather than reserving that term (as in Europe) for wine produced by a special method, from Pinot Noir, Pinot Meunier and Chardonnay grapes grown in a circumscribed region of France lying east of Paris.

Why does all this matter? The initial impetus for the creation of France's pioneer system of appellations was simple: wine fraud. France's greatest wines had, since well before the French Revolution, commanded a high price. Then came another revolution: that of industry, with its canals, its railways, its steamers and, later, its road vehicles. Transport difficulties previously ruled out the counterfeiting of local food and drink products; by the early twentieth century, ease of transport made fraud simple. 'Champagne' could begin life in the Languedoc; 'Burgundy' in Algeria. Both did. After a number of false starts, France's system of appellations d'origine contrôlée (names of controlled origin) came into being on July 30th 1935. The system has been widely imitated by France's neighbouring nations, and slowly extended to cover other products, including cheese, meat products, fruits and vegetables - even, in Provence, hay from the stony Crau plain containing (for example) clover but not horsetail.

Appellations are a way of sensually mapping the world. Their underlying premise is that not all agricultural locations are equal, and that some places on earth are better suited than others to the production of certain, memorably beautiful foods or drinks. Local customs and traditions enter into the equation, too, most notably for all of the different ways in which cow's milk can be turned into cheese. The ensemble - rock, soil, sky, plants, beasts and dabbling humanity -- is what lies behind the appeal of the French word terroir, meaning the unique quality of 'placeness' which inheres to a product. It is the comestible reason why most of us travel.

Fraud, nowadays, is a relatively minor target for the appellation-makers; even the producers of American champagne are not intending to pass off their product as French. Their case (made with some force in WTO discussions) is that 'champagne' has, by dint of prior usage, become a generic term to which they too have rights. The same argument has been used, with total success, in preventing any legal protection being afforded to Cheddar cheese which, despite originating from Cheddar in Somerset, can now come quite legitimately from anywhere. The nearest to authenticity that European legislators have been able to come is to give 'West Country farmhouse Cheddar cheese' (from Devon, Cornwall and Dorset as well as Somerset) a Protected Designation of Origin. After that, building a brand is the producer's only hope, as the Montgomery and Keen family farms have been able to do.

But as many other farmers in Somerset haven't. This, indeed, is what lends the subject of appellations its present-day urgency. Appellations provide brands for the brandless. In doing so, they help protect products and small producers who seem certain, otherwise, to be swept away in the Tescopoly torrent. They are also a way of bringing difference and diversity to an increasingly homogenised marketplace, and they provide a route of access and a banner of intelligibility to distant markets for small producers whose own names would never mean anything and whose products might otherwise be misunderstood. Jean-Marie Raveneau makes a Chardonnay which, alongside the best of the Napa, would be considered thin and sour. Why should drinkers in Sioux City trouble themselves with it? Reveal that it's Chablis, and Sioux City's keener wine drinkers may begin to understand. Drunk as Chablis, they may perceive the greatness in a wine it would have been easy (though culturally impoverishing) to dismiss.

For half a century, all the major currents in food and drink production and, more importantly still, in retailing and distribution have been moving in the opposite direction. The result is the sanitised aridity of most British and American supermarket shopping. Expressionless, inauthentic products are sold to increasingly ignorant shoppers via sickly and ingratiating marketing techniques and idiotic slogans. I bought a packet of flimsy ham from Sainsbury's recently. On the surface of its sealed plastic packaging, the company had placed an orange sticker reading 'Enjoy Summer'. Why? What did that sticker cost? Why was the money not used to source better ham? What did the summer flood victims of Sheffield and Hull make of it? Who are Sainsburys, anyway, to tell us what or what not to enjoy? I would have loved to to decline the purchase in protest - but, of course, this is the only shop selling any food within a half-hour walk of where I live, since the mediocre independent food-retailing competition which used to exist has long since been eliminated. Down my way, you shop at Sainsburys, drive or starve. Britain has a magnificent tradition of producing cooked hams, but none of them has any legal protection; consumers flail about taking a punt on things called 'Honey Roast', 'Oak Smoked' or (if you don't want it injected full of water) 'Dry Cure'. Only our ruddiest ancestors, perhaps, could tell us what we have lost.

Large companies embrace appellations at best with great wariness. For producers, appellations mean conforming to production strictures which may erode profit margins for merely tangential marketing benefits. Newcastle Brown Ale is Britain's biggest-selling bottled ale, and is the second biggest-selling imported ale in the USA; it had been brewed in Newcastle since 1927, and was an authentic example of a unique regional style (a two-brew blend with plenty of malt but low bitterness). It seemed a perfect fit for Protected Geographical Indication status, which it duly obtained and won. Then in April 2005 its brewer, Scottish Courage, closed the Tyne brewery and moved production to Gateshead for logistical reasons. Gateshead may be just down the road but Newcastle it isn't, and an application to cancel its PGI is pending. Its loss is unlikely to make any difference to Newcastle Brown Ale's sales.

For retailers, too, appellations can be an inconvenience. Production volumes are often too small for distribution around a vast estate of shops, and the minnows who cluster around the banner of an appellation can rarely afford the 'listings fees' and 'promotions payments' with which large brand owners supplement the pork-belly profit margins their products already bring to the lords of the high street. All the same, the retailers have perhaps sensed the despair of shoppers at the inadequacy of so much of what they sell, and the development of ranges like Sainsburys 'Taste the Difference' and Tesco's 'Finest' is an attempt to make money by the promise of quality rather than the hollow prize of apparent low cost or the fleeting excitement of a multi-buy deal.

The onward march of appellations, though, poses formidable challenges. Philosophically, they promise difference, yet difference is difficult and complex, and one of the articles of faith of contemporary commerce is that successful products must always be easy, comprehensible and user-friendly. The complete list of European products with a Protected Designation of Origin or a Protected Geographical Indication is often one of shattering obscurity. Puy lentils and Ossau-Iraty are on some middle-class shoppers' radar, but what about Rethel Boudin Blanc (pale pork, milk and egg sausage from the French Ardennes), Nocciole di Giffoni (hazelnuts from Italy's Salerno) or Fasolia Gigantes Elefantes Kato Nevrokopiou (giant lima beans from Drama in Greece)? Don't expect them in Asda by Christmas.

The way in which appellations are established, too, is often problematic. The French model, established to help peasant winegrowers produce an authentic and saleable product, is intensely prescriptive, with regulations which not only circumscribe the area of origin but also varieties, species and production methods. When (as in the wine world) educated, wealthy and widely travelled sons and granddaughters replace impoverished, self-taught, little-travelled grandparents, these restrictions grow tiresome and constrictive. The French state forbids François Pinault from planting Viognier or Syrah on Château Latour's magnificent gravels in Pauillac, much to Australian amusement. Nannying of this sort is uncogenial to the Anglo-Saxon spirit of libertarian pragmatism. And yet, as American winegrowers have discovered with their system of American Viticultural Areas, and Australia's winegrowers are discovering with the country's nascent system of Geographic Indications, geographical circumscription alone is often not enough to provide anything truly resembling the stamp of place dreamed of by those known (inevitably) as terroiristes. A backwash of internationally ubiquitous varieties and highly efficient winemaking interventions dissolves the picture in the sand. Scotch Beef has a PGI, but all this guarantees is that the animal from which it came was born, reared and slaughtered in Scotland. It could still be inadequately hung meat from a poorly finished, second-rate breed.

The struggle, though, matters. We love our home planet for its unfathomable diversity, the result of mutable weather systems, four-and-a-half billion years of non-stop geological excitement and the grand carnival of natural selection. Humans have been at their best in feeding themselves with unfailing ingenuity in this often hostile garden. As McDonald's and Tesco march across the globe, we are losing both the precious creations of that multi-millennial culture, and the intimacy with the natural world which can only come by sensual exploration, by smelling and tasting the physical effusions of a particular soil and a certain sky. Appellations, of course, may not save anything. It's better, though, to light a candle than to curse the darkness.

Box: Cracking the Codes
The difficulty with appellations begins, fittingly, with the system's own nomenclature and the European Union's linguistic polyphiloprogenitivism. A single marker name - like appellation - would have worked much better for those labelling and selling their products than the existing avalanche of verbiage. In English, the three main categories are PDO (standing for Protected Designation of Origin), PGI (Protected Geographical Indication) and TSG (Traditional Speciality Guaranteed). What are the differences?

PDO is the English equivalent of France's Appellation d'Origine Protégée (the more generalised umbrella under which French wine's strict Appellation d'Origine Contrôlée shelters). It can be claimed by products from a specific area whose quality and characteristics are essentially or exclusively due to that area and its inhabitants, and which is produced and processed in that area. UK PDOs include Blue Stilton and White Stilton (though neither can come from the village of Stilton, which lies in the 'wrong' county of Cambridgeshire, an anomaly with sound historical precedent), Cornish Clotted Cream, Jersey Royal Potatoes and Shetland Lamb.

PGI is ... almost the same, save that 'quality and characteristics' have become 'quality and reputation or other characteristics' which are merely 'attributable to that geographical origin'. The distinction seems principally designed to keep lawyers in work and damage the communicative aims of the system itself: folly. UK PGIs include Arbroath Smokies (hardwood-smoked haddock produced within eight kilometers of Arbroath town centre) and Kentish Ale (a PGI belonging, in effect, to Kentish brewer Shepherd Neame for ale made using Faversham well-water, a unique yeast strain and local hops).

TSG is a much looser category, indicated no more than the almost comic stipulation that its 'traditional and specific character' should 'have features which distinguish it from other products'. No geographical link, in other words. The fact that Britain's only TSG is Traditional Farmfresh Turkey inspires no more than tepid confidence in the category.