HOUSTON -- Federal prosecutors say Shipley Do-Nut Flour and Supply Company Inc. pleaded guilty to conspiring to harbor illegal immigrants.

Three former and current managers of the Houston company also pleaded guilty Friday to hiring or continuing to hire illegal aliens.

The case is part of the government's latest crackdown on employers who hire illegal immigrants.

The company pleaded guilty through its president Lawrence Shipley III to conspiring to harbor illegal immigrants.

Sentencing is scheduled for Dec. 19. Shipley Do-Nut faces a maximum fine of $500,000 and up to five years probation then.

The company has agreed to implement new procedures to prevent future violation of federal immigration laws. It will also pay $1.3 million forfeiture to the government.

Shipley Do-Nuts is a baked goods company. It has some 200 franchises across Texas, Alabama, Arkansas, Louisiana, Mississippi and Tennessee.