Tehran University of Medical Sciences Iranian Journal of Microbiology 2008-3289 18 2 2026 04 26 279 284 EN Zahra Taji Department of Food Hygiene and Quality Control, Faculty of Veterinary Medicine, Shahrekord University, Shahrekord, Iran Mojtaba Bonyadian Department of Food Hygiene and Quality Control, Faculty of Veterinary Medicine, Shahrekord University, Shahrekord, Iran Hamdallah Moshtaghi Department of Food Hygiene and Quality Control, Faculty of Veterinary Medicine, Shahrekord University, Shahrekord, Iran 2025 08 11 2026 01 29 Background and Objectives: Cronobacter sakazakii is an opportunistic pathogen associated with severe fatal infections. This study aimed to investigate the contamination of raw milk delivered to a powdered milk factory and the produced powdered milk, with C. sakazakii, and also the antibiotic resistance patterns of the isolates. Materials and Methods: During 2024, 120 raw milk and 60 powdered milk samples were collected from one of the milk powder processing plants in Shahrekord city. A peptone water medium supplemented with nutrients, followed by Cronobacter Selective Broth, was used as the enrichment medium. Chromogenic Cronobacter Isolation (CCI) agar was used to isolate the suspicious colonies. Biochemical tests were performed on the isolates. The PCR test was performed to confirm the molecular identity of the isolates. The antibiogram test was performed using the disk diffusion method on Mueller-Hinton agar. Results: A total of 14 suspected C. sakazakii colonies were isolated from the raw milk. However, the PCR test confirmed that only 2 isolates (1.67%) were C. sakazakii. Also, the results revealed that none of the powdered milk samples were contaminated with C. sakazakii. The antibiogram test showed that the isolated C. sakazakii were resistant to erythromycin, ampicillin, amoxicillin, cephalexin, and tetracycline antibiotics. Conclusion: According to the results, some raw milk is contaminated with C. sakazakii, which is resistant to certain common antibiotics. However, contamination with this bacterium was not observed in the powdered milk samples. Given the importance of C. sakazakii in infant health, further studies should be conducted on other powdered milk and infant food supplements produced in Iran to ensure their safety. https://ijm.tums.ac.ir/index.php/ijm/article/view/5675 https://ijm.tums.ac.ir/index.php/ijm/article/download/5675/1886