Hello - I have sent a glaze sample to the lab to test for cobalt leaching and awaiting results, but I am having difficulty finding online a simple number to compare the results to re: acceptable leaching.  I did find one source that quoted 1.5 ppm.  Can anyone point me in the right direction?  I'd love to be able to confidently use this glaze for food surfaces.  It passed the at-home acid and alkali baths with no apparent surface change.

thank you,
Eric Newman