Molecular identification and phylogenetic analysis of yeast strains isolated from dairy products in Isfahan, Iran

Rasoul  Mohammadi; Fatemeh  Safari; Masoud  Sami; Hamidreza  Falahati; Ziyaaddin  Keshavarzpour

doi:10.18502/ijm.v17i4.19262

Rasoul Mohammadi Department of Medical Parasitology and Mycology, Infectious Diseases and Tropical Medicine Research Center, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
Fatemeh Safari Department of Microbiology, Fal.C., Islamic Azad University, Isfahan, Iran
Masoud Sami Department of Food Science and Technology, School of Nutrition and Food Science, Isfahan University of Medical Sciences, Isfahan, Iran
Hamidreza Falahati Department of Microbiology, Food and Drug Administration, Isfahan University of Medical Sciences, Isfahan, Iran
Ziyaaddin Keshavarzpour Department of Food Science and Technology, School of Nutrition and Food Science, Isfahan University of Medical Sciences, Isfahan, Iran

DOI: https://doi.org/10.18502/ijm.v17i4.19262

Keywords: Yeast; Dairy products; Polymerase chain reaction; Sequence analysis; Iran

Abstract

Background and Objectives: Yeasts play a dual role in dairy processing, serving as beneficial fermentative agents that en- hance product quality through flavor, texture, and probiotic properties, while also posing spoilage risks if uncontrolled. This study aimed to characterize yeast isolates from industrial and traditional dairy products in Isfahan using PCR-sequencing and phylogenetic analysis.

Materials and Methods: A total of 155 dairy samples (fresh/stored, traditional/industrial) were collected. Yeasts were cultured and identified via PCR amplification and sequencing of the ITS1-5.8S rDNA-ITS2 region.

Results: Analysis of ITS sequence data identified 28 yeast strains representing eleven species across seven genera, including Saccharomyces cerevisiae (n=8) Kluyveromyces marxianus (n=6), Pichia kudriavzevii (n=4), Candida orthopsilosis (n=2), Pichia membranifaciens (n=2), Pichia cactophila (n=1), Pichia fermentans (n=1), Galactomyces candidum (n=1), Toru- laspora delbrueckii (n=1), Debaryomyces hansenii (n=1), and Kluyveromyces lactis (n=1). Phylogenetic analysis grouped isolates into two clusters. Industrial cheese and both industrial/traditional yogurts showed the highest yeast diversity and counts. Notably, C. orthopsilosis was found only in industrial milk and cheese, suggesting potential processing-related con- tamination.

Conclusion: This study highlights the diversity of yeast microbiota in dairy products and underscores the efficacy of ITS sequencing for accurate yeast identification in the dairy industry, aiding quality control and spoilage prevention.