Not really my field, but the CO1 gene is the universally accepted phylogenetic marker for bar-coding lower eukaryotes (vertebrates and invertebrates), but does not pick up fungi. 

Right: mitochondrial conserved genes such as COX1 (Cytochrome C oxydase)

Go to http://www.boldsystems.org/index.php/Public_Primer_PrimerSearch

and have yourself.

Edit:

Have a look at:

Ji, Y.-J., D.-X. Zhang, and L.-J. He. 2003. Evolutionary conservation and versatility of a new set of primers for amplifying the ribosomal internal transcribed spacer regions in insects and other invertebrates. Molecular Ecology Notes 3:581-585.

Why do you want to limit in food？ I think that using the basic method of species identification of mitochondrial genes are consistent.