Isolation, characterization, and application of bacteriophages against several pathogenic and food spoilage bacteria

Abstract

Background: Food is a fundamental requirement of everyday life, but contamination can cause food spoilage and food-borne diseases. Bacteriophage can be used as natural antimicrobials and biocontrol in the food industry without interfering with the natural microflora, as well as enhancing the safety of food products. This study is aimed to isolate and characterize bacteriophages from food and soil samples and analyze their activity as biocontrol for food safety. Methods and materials: This study used Ready-to-Eat (RTE) food such as dawet and ketoprak, seafood, and soil sample against pathogenic and food spoilage bacteria such as V. cholera, V. parahaemolyticus, E. cloacae, EPEC, EHEC, ETEC, B. cereus, and B. subtilis. Bacteriophage isolation, enrichment, and titer determination were done using agar overlay assay method. Bacteriophage then screened against pathogenic bacteria by the Efficiency of Plating (EOP) method. The inhibition of bacteria were determined using Minimum Inhibitory Multiplicity of Infection (miMOI) method and for the bacteriophage morphology was determined using Transmission Electron Microscopy (TEM). Results: The positive result of bacteriophage isolation was shown by the formation of clear plaque on plate, indicating bacteriophage lyses the bacteria. The titer determination of bacteriophage (>108 PFU/mL) tend to be more effective to reduce bacterial counts in foods which proved by 95.41% of EHEC and 99.24% of ETEC can be reduced by bacteriophage from dawet, while 62.15% of EPEC and 80.11% of ETEC can be reduced by bacteriophage from ketoprak. Bacteriophage that attacked V. parahaemolyticus had an efficiency of 99.03% and a concentration of 2.28 × 1010 PFU/mL. Bacteriophages that attacked V. cholera had an efficiency of 99.87% and a concentration of 1.08 × 108 PFU/mL. Bacteriophages that attack E. cloacae had an efficiency of 95.36% and a concentration of 1.81 × 1010 PFU/mL. Based on the TEM result, all the isolated bacteriophage were suspected from family Myoviridae. Conclusion: This study revealed that all the isolated bacteriophage have great potential to be used as biocontrol for food safety. Further study still needs to be conducted to characterize and analyze the bacteriophage against B. cereus and B. subtilis.