Try:
<cfcontent type="application/vnd.ms-excel">
instead of
<cfcontent type="application/msexcel">
Also, for future reference, you CAN create a CSV file whose
elements contain commas if you qualify the offending fields with
quotation marks:
Field 1, Field 2, "Field 3, and a comma", Field 4
Excel will be able to open those up just fine.