Incidence of Mycotoxic Molds in Domestic and Imported Cheeses12

Domestic and imported cheeses were studied to determine the incidence of mycotoxin producing molds. The total incidence of molds in visibly non‐moldy cheese was very low. Isolation of molds from plate counts, and directly from samples, showed that the major portion of the flora was made up of Penicillium species; 86% in domestic cheeses and 80% in imported cheeses. Many of the Penicillium isolates were capable of growing at low storage temperatures. Mold counts done at 5°C, and prolonged storage of cheese samples at 5°C indicated a potential for considerable mold growth on cheese during refrigerated storage. While the overall incidence of known mycotoxin producing molds was low, a number of potentialy toxic species were found, including P. cyclopium, P. viridicatum, A. flavus and A. ochraceus. These species accounted for 4.4% of all the isolates from domestic cheeses and 4.0% from imported cheeses. Screening of all mold isolates for production of several known mycotoxins showed that a number of isolates (14.1% of all molds in domestic cheeses and 11.5% in imported cheeses) were capable of producing certain mycotoxins including patulin, penicillic acid, ochratoxin A, citrinin and aflatoxins.