|Dombrink Kurtzman, Mary Ann|
Submitted to: Journal of Food Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 23, 2007
Publication Date: November 1, 2007
Citation: Dombrink Kurtzman, M., Mcgovern, A.E. 2007. Species-specific identification of Penicillium linked to patulin contamination. Journal of Food Protection. 70(11):2646-2650. Interpretive Summary: Total genomic DNA of twelve different species of the genus Penicillium known to make the mycotoxin patulin was analyzed. Specific primers were designed to identify the different species based on the gene sequence coding for a particular enzyme present in the pathway for production of patulin. From this work, it is now possible to identify all known patulin-producing species of Penicillium by species-specific primer sets. From this work, it is possible to test for the presence of patulin-producing molds in apple juice and apple products. Both producers of apple juice and consumers benefit from this food safety research. Patulin, which is common to apples, is one of two mycotoxins regulated by the U.S. Food and Drug Administration.
Technical Abstract: Certain species of Penicillium have been reported to produce the mycotoxin patulin, and research was undertaken to identify these using oligonucleotide primer pairs. Species examined were found in food, plants, and soil, and were reported to produce patulin. Penicillium expansum is the most commonly detected species linked to the presence of patulin in apple juice. At least ten different enzymes are involved in the patulin biosynthetic pathway, including the isoepoxydon dehydrogenase (idh) gene. Based on nucleotide sequences previously determined for the idh gene in Penicillium species, PCR primers were designed for the species-specific detection of patulin-producing species. The 5' primers were based on differences in the second intron of the idh gene. To ensure that the primer pairs produced a PCR product restricted to the species for which it was designed, and not to unrelated species, all of the primer pairs were tested against all of the Penicillium species. With one exception, it was possible to detect a reaction only with the organism of interest. The primer pair for P. griseofulvum also amplified DNA from P. dipodomyicola, a closely related species; however, it was possible to distinguish between these two species by doing a second amplification, using a different primer pair specific only for P. dipodomyicola. Consequently, by using different primer sets, it was possible to identify individual patulin-producing species of Penicillium.