In the brief radio interview of March 30th Jim Humble said that one could use lemon juice,good as citric acid as it had a pH of 10 ?! Unsure if he was talking about something else as the audio stream became dead.
"So as per the FDA these fruits have the following pH:(approximative)
Endourology(as per the medical dictionary):the branch of urologic surgery concerned with closed procedures for visualizing or manipulating the urinary tract
"Citric acid produced by cultures of Aspergillus Niger (the black stuff-mold we see around kitchen sinks, etc.).which are feed a sucrose or glucose-containgng medium to produce citric acid.
The source of Sugar is corn step liquor,molasses,hydrolyzed corn starch or other inexpensive sugary medium.After the mold is filtered out the resulting solution,citric acid is isolated by precipitating it with lime(calcium hydroxyde) to yield calcium citrate salt,from which acid is regenerated by treatment with sulfuric acid."