Effect of environmental stresses on the sensitivity of Enterobacter sakazakii in powdered infant milk formula to gamma radiation.
OBJECTIVE
To evaluate the effect of starvation, heat, cold, acid, alkaline, chlorine and ethanol stresses on the resistance of Enterobacter sakazakii in powdered infant milk formula (PIMF) towards gamma radiation.


RESULTS
Stressed cells of E. sakazakii ATCC 51329 and four other food isolate strains were mixed individually with PIMF, kept overnight at room temperature, and then exposed to gamma radiation up to 7.5 kGy. The D(10)-values were determined using linear regression and for the stressed E. sakazakii strains these values ranged from 0.82 to 1.95 kGy.


CONCLUSIONS
Environmental stresses did not significantly change the sensitivity of most E. sakazakii strains to ionizing radiation.


CONCLUSIONS
Data obtained established that most forms of environmental stress are unlikely to significantly enhance the resistance of E. sakazakii strains to lethal, low dose irradiation treatment.
Department of Nutrition and Food Technology, Jordan University of Science and Technology, Irbid, Jordan. tosaili@just.edu.jo
T
T
Osaili
A
A
Al-Nabulsi
R
R
Shaker
M
M
Ayyash
A
A
Olaimat
A
A
Abu Al-Hasan
K
K
Kadora
R
R
Holley
D000143:Acids / Q000494:pharmacology; D000468:Alkalies / Q000494:pharmacology; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D002713:Chlorine / Q000494:pharmacology; D003080:Cold Temperature; D044083:Cronobacter sakazakii / Q000528:radiation effects*; D000431:Ethanol / Q000494:pharmacology; D005516:Food Microbiology; D005720:Gamma Rays; D006358:Hot Temperature; D006801:Humans; D007223:Infant; D041943:Infant Formula; D016014:Linear Models; D050296:Microbial Viability
D000143:Acids; D000468:Alkalies; D000900:Anti-Bacterial Agents; D000431:Ethanol; D002713:Chlorine