Isolation and virion morphology classification of coliphages from local foods

M. Nur ilida, G.H. Tan, S. Nur Baizura and M.N. Mohd Effendi

Abstract

Bacteriophages are viruses that exclusively target and reproduce within bacteria. Bacteriophages that infect Escherichia coli (E. coli) are known as coliphages. The potential use of bacteriophages to control bacteria of importance to food quality and safety has been the subject of recent review. This study was conducted to isolate coliphages from local foods. The isolated coliphages were viewed under the transmission electron microscope to classify them based on their morphology. Two E. coli strains (E.coli ATCC 25922 and E.Coli UN) were used and a total number of 96 food samples were tested for this study. The results showed that a total of 25 coliphages were successfully isolated from the tested food samples. Out of the 25 isolates, 23 were obtained from E.coli ATCC 25922 and two from E. coli UN. All isolates were obtained from raw chicken (15 isolates), raw meat (4 isolates), fresh milk (4 isolates), fresh coconut milk and fresh ulam (1 isolate each). Most of these coliphages (23 isolates) formed circular clear plaques with diameters ranging from 2.0 to 6.0 mm. The other two isolates formed turbid areas with one small halo zone in the middle. The appearance of the isolates viewed under the transmission electron microscope suggested that they belonged to the family of Myoviridae, Siphoviridae and Podoviridae. However, more precise studies need to be done on the isolates to confirm their potential uses as biological control agents of E. coli in the food industry.

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