One authoritive site offers this:
Edwin S. Lowe.was a toy salesman from New York. One evening in December 1929, while he was on his way to Georgia, he decided to stop by a carnival to give him some time out. He noticed there were many people playing and watching this lotto-like game called Beano. Its form is as similar as our bingo today, although they used beans as markers and numbers. Whoever completes the pattern has to shout Beano to be recognized as a winner. The caller of that booth told Lowe that he adapted this game from a lotto game in Germany; he just made several adjustments and improvements. Lowe tried this with several of his friends and it was a hit. One of his friends was so excited to win, when she actually won, instead of shouting "Beano" she shouted "Bingo". Lowe thought it was catchy so he adapted it. Bingo became an instant hit that with his earnings his company was able to thrive.