SCOTT, La.—Few would dispute that southern Louisiana is boudin heaven. The local version is a sausage made of pork, rice and various seasonings. Trickier to answer is which of three competing Cajun communities is its official mecca.

In April, Louisiana's state legislature bestowed the coveted mantle of Boudin Capital of the World on Scott, a bustling town of 8,600 on Interstate 10—the busy east-west highway linking Houston and New Orleans. It churns out 1.3 million pounds of the sausage a year.

"No...