When it comes to plastic milk cartons, dairies have choices. They can buy blow-molding equipment to make gallon and half-gallon bottles themselves. They can outsource the task to a supplier who sets up an on-site shop. Or they can buy empty jugs and have them trucked in.
Anderson Erickson Dairy, Des Moines, Iowa, is one dairy that blows its own bottles. After molding, excess resin is trimmed from bottles (and re-melted for use the next time around), which are tested for leaks and are then conveyed to the filling room. No sanitizing is required.