A giant food festival featuring organic delicacies and world-renowned chefs opened in the Italian city of Turin on Thursday, with hundreds of exhibitors and thousands of visitors expected.

The five-day Salon of Taste, which advocates tasty and fair nutrition, hosts 910 exhibitors and 288 producers of indigenous products at risk of extinction.

The products include wild coffee from Ethiopia, purple onions from Spain, and Moroccan cumin.

Organised by the Slow Food gastronomic campaign group, the Salon brought together 180,000 visitors in its previous edition in 2008.

The festival will coincide with the fourth edition of the Terra Madre network, organised around the world into "food communities."

The network brings together advocates of sustainable production from farmers to distributors, as well as chefs and scientists.

Some 4,500 delegates from 160 countries are expected for the Terra Madre conference, which runs until Monday.

This year the network of food communities, cooks, academics, youth and musicians from all over the world will focus on the defence of indigenous cultures.

This year's meeting was inaugurated by talks given by representatives of five ethnic groups - Aborigines from Australia, Gamos from Ethiopia, Kamchadals from Russia, Samis from Sweden and Guaranis from Brazil.

Slow Food was founded in 1986 in the Turin region by Carlo Petrini, a food critic and sociologist, in reaction to the opening of the first fast-food restaurants in Italy.

The association aims to educate the public on different tastes, defend biodiversity and promote a food production model that is respectful of the environment and cultural identities.

Today the movement has 100,000 members in 163 countries.