Been researching this one a bit because of a weird fetish for learning it seams.
Found out the penicilium genus is one of the most common spore types in the world, often the most common cause of spore related infections, and its known for spoiling of food. This spore is known for having a green/blue tinting and sometimes yellow/gold. I thought it was strange for saying yellow/gold untill I read an article on the discovery of penicillium chrysogenum species in the 1940's on a spoiling cantaloupe. The species isnt particuarily high yield compared to the other species in the family, but it takes to culturing in containers much better than the rest of the family.
One of the primary reasons why its unrecommended to manufacture the natural forms of penicillin is due to the penicilium genus containing toxins if you misidentify the species. Some of the penicilium spores produce neurotoxins which can kill you if ingested. Otherwise its quite easy to produce and find the spores, i might just post the spore ordering site for penicillium chrysogenum as proof =P.
As far as the procedure for collecting the penicillin... Its simply a byproduct that needs to be centrifuged till it seperates, and filtered out. So yes, the "penicillin soup" is actually the most accurate way its manufactured. Sadly the nitty gritty of this process appears closely guarded because I can't find much info besides what has already been mentioned.
I hope this info helps clear things up.
(References)
http://www.sci.muni.cz/mikrob/Miniatlas/pen-chr.htm
http://www.doctorfungus.org/thefungi/penicillium.htm
http://windintheroses.googlepages.com/penicillin_diy
(historical info)
http://www.uwlax.edu/faculty/volk/toms_fungi/nov2003.html
(insulin production)
http://www.microbiologyprocedure.com/industrial-microbiology/penicillin-production.htm
(order your samples here lol)
http://www.connecticutvalleybiological.com/index.php
