thracian bananas and poor depiction.
1) Thracians weren't some swarthy exotic people, they were far more fair then the romans on average, Herodotus described the average thracian as being a red haired pale skinned person who worshiped gods that looked like they did(as everyone else did in their regional religions)
2) bananas weren't introduced to rome by thracians, rome controlled egypt, it was a roman province at one point and a vital trade route even before the suez canal was contructed.