1. A carrier for transporting a plurality of articles on a convey line of a microwave heating system, wherein each of said articles comprises a pouch having a base portion and a top portion, where said base portion is at least twice as thick as said top portion, said carrier comprising:a frame comprising first and second spaced apart end members; and
an upper support structure and a lower support structure extending between said first and said second end members and configured to secure said articles in said carrier,
a pouch receiving space is defined between an upward facing surface of said lower support structure and a downward facing surface of said upper support structure,
said downward facing surface presents a series of upper recesses spaced from one another by an upper recess spacing,
said upward facing surface presents a series of lower recesses spaced from one another by a lower recess spacing and said upper recesses, and
each of said lower recesses is configured to receive the base portion of one of said pouches so as to secure the pouch in said pouch receiving space.