All foreign participants of the 2nd International Congress on Food Technology must have a valid passport during entering Turkey. Since Turkey demands an official entry visa from citizens of several countries, it is better to check with a Turkish Consulate in your country to determine if you need a visa, before your departure to Turkey. In some cases, you can obtain a visa upon arrival at the airport for a small fee.
It is an official endorsement giving the permission to enter or leave a country by the Consulate and/or the Embassy of that country.
For further detailed information, please visit the related web page of Republic of Turkey Ministry of Foreign Affairs, that is: http://www.mfa.gov.tr/visa-information-for-foreigners.en.mfa