Actually, "filled cheese," as defined by the U.S. government,
does contain milk. The difference between "cheese" and "filled cheese" is that filled cheese ALSO contains "butter, animal oils or fats, vegetable or any other oils."
This is very similar to "mixed flour," which contains things other than just flour in it.
See relevant definition page below.
Jim
Reference:
The Code of Federal Regulations of the United States of America, Title 26, Parts 40 to 169, Revised as of January 1, 1966, Office of the Federal Register, U.S. Government Printing Office, Washington, D.C., 1966, page 95
