A rapid method for identifying byssochlamys and hamigera

Abstract

Heat-resistant fungi, genera Byssochlamys, Talaromyces, Neosartorya, and Hamigera, contribute significantly to the spoilage of heat-processed acidic foods, due to the formation of heat-resistant ascospores. Here, we first evaluated the differences in the β-tubulin gene between Byssochlamys and Hamigera and developed specific primers to identify the Byssochlamys species fulva, nivea, and spectabilis, and Hamigera. Using primers designed for B. fulva and B. nivea (B1F/1R), specific PCRr products were detected for B. fulva and B. nivea, as well as B, langunculariae and B. zollerniae, two closely related species. Similarly, the Pae4F/4R-1 and H2F/2R primers produced specific PCRr products for B. spectabilis and Hamigera, respectively. Using these three primer sets, strains involved in acidic food spoilage and environmental contamination were not detected. The detection limits of all primer sets were 1 ng of DNA by PCRr and 10 pg of DNA by nested PCRr. Each PCRr assay was specific, even if the sample was contaminated 1,000-fold by other fungal DNA. Thus, this method has proved to possess an extremely high degree of specificity. Copyright © International Association for Food Protection.