Safety evaluation of bacteriophages for application as sanitizers

Abstract

To evaluate the safety of bacteriophages for application of sanitizer, endotoxin content and cell cytotoxicity of two Escherichia coli and four Staphylococcus aureus phages were determined. Endotoxin ratio was determined by the Limulus amebocyte lysate (LAL) assay as a test for representative biological endotoxin content. The average endotoxin average content of the 9 log PFU/mL lysate was 18.6 EU/mL and that of the 10 log PFU/mL lysate was 5.9 EU/mL, suggesting that the phage lysate was not suitable for clinical applications, but suitable for food pathogen control applications. To confirm the cell cytotoxicity of the phage lysates, MTT assay was performed using Raw 264.7 cells treated with 9 log PFU/mL phages. Results of the assay indicated that the phage lysates did not significantly decrease the cell viability (p>0.05). These results indicated that bacteriophages would be suitable as a food safety sanitizer.