Detection of Brucella spp. in raw milk and dairy products of traditional domestic dairy sale centers by Real-Time PCR in Semnan

Articles in Press

Document Type : Original Articles

Authors

1 Food Hygiene Department, Faculty of Veterinary Medicine, Semnan University, Semnan, Iran

2 Pathobiology Department, Faculty of Veterinary Medicine, Semnan University, Semnan, Iran

3 Nuclear Science and Technology Research Institute, Tehran, Iran

Abstract

Introduction: Brucellosis, also known as Malta fever, is a significant zoonotic infectious disease in Iran, with considerable public health and economic complications. Human infection is primarily acquired through the consumption of unpasteurized milk and dairy products. Conventional diagnostic approaches, such as culture and serology, are limited by low sensitivity, biosafety risks, and potential cross-reactivity. Molecular methods, particularly Real-Time PCR, offer greater sensitivity and specificity. Objectives: This cross-sectional study, investigated the presence of Brucella spp. In raw milk and traditional dairy products (cream, cheese, and ice cream) collected from local markets in Semnan, Iran. Material and Methods: A total of 95 samples were analyzed using Real-Time PCR with SYBR Green dye, targeting the bcsp31 gene for genus-level detection and species-specific primers for Brucella abortus and Brucella melitensis. Also, the limit of detection (LOD) was evaluated using the serial dilution of Brucella standard strain. Results: Results revealed that among the samples tested, four samples were positive for Brucella spp. specifically, three samples were confirmed Brucella abortus, and one sample was identified as Brucella melitensis. Following propagation, DNA fragments of 498 bp and 731 bp, corresponding to Brucella abortus and Brucella melitensis, respectively, were successfully detected in the infected samples. Moreover, no significant overall difference in Brucella prevalence was found across products and Bacterial load analysis revealed higher median CFU in cheese compared to milk and ice cream. Conclusion: These findings highlight the presence of Brucella contamination in dairy products sold through informal channels, emphasizing the need for improved monitoring, strict control strategies, and consumer education to reduce disease transmission.

Keywords

Archives of Razi Institute

Articles in Press, Accepted Manuscript
Available Online from 05 January 2026

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