Penicillium verrucosum was initially incorrectly placed in synonymy with the species Penicillium viridicatum by Raper and Thom. Later, after disagreements arose upon the identification and naming of these fungi, their growth rates, mycotoxin productions and sources were observed. Careful observation concluded that P. verrucosum and P. viridicatum were indeed separate species. Experimental results showed that the mycotoxins ochratoxin A and citrinin are produced by P. verrucosum but not by P. viridicatum.
