Effect of environmental stresses on the sensitivity of Enterobacter sakazakii in powdered infant milk formula to gamma radiation

• Published in: Letters in applied microbiology Vol. 47; no. 2; pp. 79 - 84
• Main Authors: Osaili, T, Al-Nabulsi, A, Shaker, R, Ayyash, M, Olaimat, A, Abu Al-Hasan, A, Kadora, K, Holley, R
• Format: Journal Article
• Language: English
• Published: Oxford, UK Oxford, UK : Blackwell Publishing Ltd 01.08.2008; Blackwell Publishing Ltd; Blackwell Science
• Subjects: Acids - pharmacology; Alkalies - pharmacology; Anti-Bacterial Agents - pharmacology; Biological and medical sciences; Chlorine - pharmacology; Cold Temperature; Cronobacter sakazakii; Cronobacter sakazakii - radiation effects; D-value; Enterobacter sakazakii; Ethanol - pharmacology; Food Microbiology; Fundamental and applied biological sciences. Psychology; gamma radiation; Gamma Rays; Hot Temperature; Humans; Infant; Infant Formula; infant milk formula; Linear Models; Microbial Viability; Microbiology; stresses; infant milk formula; Applied microbiology; stresses; Dried milk; Stress; Sensitivity; Enterobacter; Gamma radiation; Enterobacter sakazakii; D-value; Bacteria; Infant formula; Enterobacteriaceae
• ISSN: 0266-8254; 1472-765X
• DOI: 10.1111/j.1472-765X.2008.02388.x

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. 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 D₁₀-values were determined using linear regression and for the stressed E. sakazakii strains these values ranged from 0·82 to 1·95 kGy. Environmental stresses did not significantly change the sensitivity of most E. sakazakii strains to ionizing radiation. 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.