Photoreactivation of enterohemorrhagic Escherichia coli following UV disinfection

The objective of this study is to determine the susceptibility of enterohemorrhagic Escherichia coli O157:H7 and O26 to UV radiation at 254 nm and photoreactivation. The conclusions obtained in this study can be summarized as follows. (1) The dose of UV light required for 90 and 99% inactivation of EHEC O157:H7 was 1.5 and 3.0 mW s cm−2, respectively. (2) The dose of UV light required for 90 and 99% inactivation of EHEC O26 without photoreactivation was 5.4 and 8.1 mW s cm−2, respectively. (3) Apparent photoreactivation with visible light from a fluorescent lamp was observed in EHEC O26 but not in EHEC O157:H7. (4) The dose of UV light required for 90% inactivation of EHEC O26 after photoreactivation was 12.0 mW s cm−2.