There is no physical way to determine the difference between an Africanized bee and a common European bee. None whatsoever.
You can, however, easily tell the difference based on their behavior. Regular bees will give you about nine seconds of being too close to the hive before deciding you're a threat and then attacking you. So it's pretty easy to just walk past them without any screams. And if you do get them after you, they'll consider you to be 'chased off' after about 300 feet.
Africanized bees do not roll this way. They give you half a second of being too close before they decide it is time to completely f*ck your shit up and empty the entire hive--tens, maybe hundreds of thousands of angry, angry bees. When you run, flailing and crying and soiling yourself while screaming "JESUS CHRIST I'M COVERED IN BEES," they will chase you for over half a mile.