How can I measure carcinogenic risks of an M-ENDO-Agar LES substrate after heat destruction?
Most assays of carcinogenicity are designed to measure DNA damage. The 2 most common of those assays are the Ames test and the Comet Assay.

The Ames test uses a special set of strains of bacteria that have known phenotypes. You expose the bacteria to the suspected carcinogen and then look for changes in phenotype. Different strains will be susceptible to different types of mutations, deletions, insertions, frameshifts, etc.

The comet assay uses mammalian cell lines. You have to suspend the cells in an agar and break them up. This will create little pockets of cell debris in the agar. You fluorescently stain the DNA and run an electric current through it. If the DNA is damaged and broken up, it will migrate through the gel, creating tails, hence the "comet". If the DNA is intact, it will not migrate.

I've never done either assay, just heard about them in class. Wikipedia has more detail than I do.

http://en.wikipedia.org/wiki/Ames_test
http://en.wikipedia.org/wiki/Comet_assay