Document Type : Research Article
Authors
1
Department of Microbiology, Faculty of Veterinary Medicine, Islamic Azad University, Babol Branch, Babol, Iran
2
Department of Microbiology, Faculty of Basic Sciences, Islamic Azad University, Amol Branch, Amol, Iran
3
2Department of Microbiology, Faculty of Basic Sciences, Islamic Azad University, Babol Branch
4
Department of Biology, Qaemshahr Branch, Islamic Azad University, Qaemshahr Branch
5
Department of Microbiology, Faculty of Basic Sciences, Islamic Azad University, Chalous Branch
6
Department of Microbiology and Immunology, Faculty of Medicine, Nayshabur University of Medical Sciences, Nayshabur, Iran
10.22034/ijmcm.2024.710191
Abstract
Bacteriophages have attracted attention due to their unique abilities in controlling microbial contamination and maintaining the quality of food products. The stability of phages against changes in pH and temperature plays a significant role in their applications in the food industry and public health. This study evaluates the pH and thermal stability of bacteriophage PhE8 and its role in reducing the microbial load in milk contaminated with Escherichia coli at two temperatures of 4°C and 25°C. The stability of bacteriophage PhE8 against pH and heat was measured. The activity of the bacteriophages was assessed using Plaque Forming Unit (PFU). To investigate the antimicrobial activity of PhE8, 5 ml of pasteurized milk was treated with 100 µl of Escherichia coli (E8) bacteria along with 100 µl of phage suspension. The samples were stored for four days at 4°C and 25°C. Electron microscopy revealed that the isolated phage has a polyhedral head and a contractile tail. The latent period was 10 minutes. Phage PhE8 was stable within the pH range of 4 to 12 and remained stable at temperatures between 30°C and 60°C for 30 minutes. The studied phage demonstrated high potential in reducing the microbial load in milk at 4°C. The high stability of the phage at normal pH and its significant decrease in activity at high temperatures provide useful information for the practical use of phages in real-world conditions.
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