Besides the pork, spicy sliced grilled beef and boiled chicken are also popular among diners at Thai restaurants in both markets, said NFI president Petch Chinabutr.
He said diners in the EU preferred pork and beef, while those in the US like more of the chicken and beef. Diners indicated that they like the strong taste and the good smell of ground roasted rice, a key ingredient that differentiates Thai food from other countries.
The nam tok menu has surpassed earlier popular Thai dishes like massamun curry, phad Thai and tomyam soup.
Mr Petch said the survey result indicated that foreigners knew more about Thai spices now, so the institute would continue promoting Thai ingredients abroad.
For the first half of this year, Thailand exported a total of 600 billion baht of foods. The institute expects total food exports for the year will reach the target of 970 billion baht, an increase of 6% from 2013.
The institute has a target to see the export of foods from Thailand reach one trillion baht in 2015.
The video clip above, uploaded to YouTube by YingsakfoodTV, shows Thailand's renowned chef Yingsak Jonglertjesdawong demonstrating how to cook nam tok tub moo, or spicy sliced grilled pork liver.