Main content area

Resistance of various shiga-toxin producing Escherichia coli (STEC) strains and serogroups to infra-red and pulsed UV radiation and effect of nalidixic acid adaptation

Chintagari, Sailaja, Jadeja, Raviraj, Hung, Yen-Con
Lebensmittel-Wissenschaft + [i.e. und] Technologie 2019 v.102 pp. 356-363
Escherichia coli O104, Escherichia coli O157, Escherichia coli O26, acid tolerance, nalidixic acid, serotypes, ultraviolet radiation
The efficacy of Infra-red radiation (IR) and Pulsed UV (PUV) for the inactivation of parent (Par) and Nalidixic acid adapted (Nal) strains of Escherichia coli O157:H7, top six shiga-toxin producing E. coli (E. coli O26, E. coli O45, E. coli O103, E. coli O111, E. coli O121, and E. coli O145 and E. coli O104) along with nonpathogenic surrogates were evaluated. It was observed that significant (P < 0.05) differences in D values between E. coli O157Par and non-O157Par as well between the strains in the same serogroup when subjected to IR or PUV treatment. Individual nalidixic acid adapted strains and serogroups show varied levels of sensitivity towards IR and PUV. Calculated D values of parent strains except for E. coli O157:H7 strain E932 and E009 were significantly higher (P < 0.05) than the Nal strains when subjected to IR radiation. Strain 5Par of E. coli O157:H7 was the most resistant among all the parent strains and serogroups when subjected to PUV treatment with a D value of 1.01 J/cm2 and serogroup E. coli O26 was the least resistant with a D value of 0.63 J/cm2. Nal counterparts of strains 4 and 5 of E. coli O157:H7 were significantly (P < 0.05) more sensitive to PUV than Par strains.