Some buys are better than others. The caveat emptor rule obviously applies, particularly to Turkish 'herbal Viagra', and stalls where it is prominently displayed are perhaps best avoided.

Real Iranian saffron is available, but 'Turkish saffron' is dried safflower, which imparts a similar colour but little flavour. Pre-packaged spices are often of inferior quality, and/or well past their sell-by dates. Buy them loose and be sure to taste and sniff.

Stores specialising in a narrower range of foodstuffs are likely to be the most reliable, and good deals can be had on cardamom, sumak, cinnamon bark, nuts, dried fruit, and pastries and confectionery, including lokum or Turkish delight.

Those in the know go to Erzincanlilar for dried honeycomb, and Malatya Pazari for fruit, nuts and Iranian saffron. Pandeli's restaurant, upstairs from the main entrance, is an Istanbul institution.

Outside the west entrance are narrow streets where shops roast coffee and sell olives, olive oil, Turkish cheeses, cured meats and kitchen equipment. Kurukahveci Mehmet Efendi, just outside the building, is the place for Turkish coffee.

The physical structure of the Mercat de St Josep de la Boqueria in Barcelona is a little younger than Misir Carsisi, dating from the mid-19th century, but the market's origins can be traced back to the 13th century.

Today La Boqueria, as it is generally called, has 300 stalls, many of which are family concerns that have been there for decades. It is known, among other things, for the range of fresh fruit juices, and for both the range and excellence of the fish, meat, fruit, vegetables and confectionery it offers.

It, too, is both a tourist attraction - located on the famous La Rambla boulevard - and a genuine local market. It is a place where the city's famous chefs, including Ferran Adria, come to source produce and find inspiration. Although far from the cheapest market in Barcelona, it is considered the best, and, by many, the best in Europe.

Adria is a particular fan of the market cafe, Bar Pinotxo, which offers excellent traditional tapas rather than the more avant-garde fare for which Adria's El Bulli was known. It can get crowded, but there are several good alternatives in the market, including El Quim and Bar Central.

Another chefs' favourite in the market is Petras Fruits del Bosc, for an extraordinary range of edible fungi, not to mention - if you are into that sort of thing - edible insects. Owner Lorenc Petras recommends scorpion lollipops. He started selling them as a joke and discovered that they sold - he thinks mostly as conversation pieces.

One reason chefs like the market so much is that the stall owners put as much effort into pleasing the eye with their displays as they do into composing a plate.

Attention to visual detail is also a feature of the food markets of Paris, and there too chefs find inspiration from interaction with the stall owners and the produce on display.

Philippe Labbe, who moved from a two Michelin-star restaurant in Monaco to become executive chef of the Shangri-La Hotel Paris, is awaiting the results of his first Michelin assessment for the hotel's popular L'Abeille restaurant. He considers himself fortunate now to have one of his favourite markets just around the corner.

'I go to the market to talk to the suppliers, which is very important. I want to know what the choices are. The quality at the Marche Avenue du President Wilson is very good,' says Labbe.

Unlike La Boqueria and Misir Carsisi, which operate daily, the President Wilson is a farmers market - with many of the stalls manned by the people who grow, catch or prepare the produce - and runs from 7am to 2.30pm on Wednesdays and Saturdays.

It is highly rated by chefs and gourmets for its fresh seafood, cheese, country bread, and fruits and vegetables. Labbe says he particularly likes the seafood, and goes regularly to the fruit and vegetable stall run by Joel Thiebault, whose produce he and many other French chefs swear by.

Thiebault's family were among the first stallholders when the market on this street opened in 1873, and he still mans his own stall. Several of Paris' leading restaurants are on his list of clients, and the vegetables he grows just outside the city have inspired a coffee table book, Les Legumes de Joel (Joel's Vegetables).

Another stall worth visiting and manned by the producer is Foies Gras Lafitte, where Jean Marie Gremillet sells melt-in-the-mouth duck and goose liver products that you can try before you buy.

The Avenue President Wilson Market has a glamour that somehow eludes London's Borough Market, despite its occasional appearances in films such as Lock, Stock and Two Smoking Barrels and Bridget Jones's Diary. But if you want a slightly grittier gourmet retail experience than the city's famous department store food halls, it's still the best London has to offer.

Borough is also one of the oldest market sites in the world. This kind of business has been going on around the present London Bridge location since Britain was occupied by the Romans, although that heritage hasn't saved the area from losing historic buildings to a rail expansion programme.

Some stalls are open all week, but Borough is at its best from Thursday to Saturday when everything is open from 11am to 5pm, 12pm to 6pm, and 8am to 5pm respectively.

It is not a place for people squeamish about the origins of what they eat. Endangered cod stare blindly up from mounds of ice; rabbits, hares and pheasants hang still furred and feathered.

On the other hand it is a good place to grab a quick lunch if you don't feel the need to sit down. Locals and tourists alike queue up at stalls offering wild boar sausages, port and stilton burgers, and traditional English staples such as pork pies and fish and chips, then eat them while wandering round the stalls.

Alternatively, you can sit down with a plate of molluscs and a pint of Guinness at Wright Brothers Oyster and Porter House. The market pubs offer a selection of real ales.

Take-homes, apart from meat, fish, fruit, vegetables and preserves, also include a large range of cheeses, available from market stalls and from the Borough branch of the famous Neal's Yard Dairy artisanal cheese shop.

Drinks include everything from organic juices to wine and micro-brewery beers.

Construction and renovation works are affecting Borough Market's operations, but the effect is comparatively minor compared to what the world's biggest wholesale fish market is threatened with.

By 2014, Tokyo's metropolitan government plans to move the Tsukiji fish market, which handles 2,000 tonnes of marine produce a day, to another site far from the city centre, although the plan has met with widespread opposition.

Yuji Imaizumi, of the Mandarin Oriental Tokyo's Sushi Sora restaurant, a master of Tokyo's Edo-mae sushi cuisine, is concerned that if the market is moved, he and other sushi chefs will be unable to go to inspect the fish they work with at the time of optimum freshness.

'It is extremely important to go to the market every morning because sushi chefs decide the day's menus only when they have seen and bought the best available fish at the market,' says Imaizumi.

Tourists, too, will miss out on a great opportunity to breathe in the - very fishy - early morning air of the frenetic market, and to jump hurriedly out of the way of short-tempered market porters driving heavily tuna-laden three-wheeled carts with utter disregard for pedestrian safety.

Getting up in time to queue up for admission to the 5.30am tuna auction is a bit too much of an effort for many, and the seafood wholesale area is only open to visitors after 9am, but it is possible to visit the outer market, and the many small restaurants serving sushi made from fish that came from the market only an hour or so before.

If the market moves, according to Imaizumi, it is not clear whether the 'old-established, good-quality shops' in the area will move with it, but certainly the sushi in the area will never be as fresh again. Get it while it lasts.

Market Drifters

Misir Carsisi

La Boqueria

Marche Avenue du President Wilson

Borough Market

Tsukiji Market

Under the radar

Borough has been the poster child for food markets in London, if not Britain, since 1276 if you count the original site. But just a bit further east, along the Thames in Bermondsey, another foodie enclave has cropped up.

Put off by the increasing number of tourists visiting Borough Market, foodies are migrating to the area around Maltby Street. It's not a market as such, but a group of producers and retailers who are independently setting up stalls under the railway arches just off Tower Bridge Road.

That three of London's most renowned food specialists - Monmouth Coffee Shop, Neal's Yard Dairy and St John Bakery, part of the Fergus Henderson 'nose to tail' stable - have opened outlets there lends culinary kudos to the site.

And more have joined them. Now you can buy wild mushrooms and top-notch vegetables from Booth's, organic meat from Jacob's Ladder Farms, bacon from Fern Verrow and Polish sausages from Topolski, as well as French and Italian wines from Aubert & Mascoli.

Bermondsey is also becoming a destination for great restaurants, including two by Jose Pizarro, the respected Spanish chef. His Jose tapas bar on Bermondsey High Street is crammed most nights due to the brilliant bite-size food and wide selection of sherries by the glass, and he's about to open Pizarro's, a sit-down Spanish eatery on the same street.

Further along is Zucca, serving solid, unpretentious Italian dishes.

For the time being at least, there's not enough takeaway stands in Bermondsey to draw in the tourists. Long may that continue.