RESUMEN
AIM: 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. METHODS AND 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. SIGNIFICANCE AND IMPACT OF THE STUDY: 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.
Asunto(s)
Cronobacter sakazakii/efectos de la radiación , Microbiología de Alimentos , Rayos gamma , Fórmulas Infantiles , Ácidos/farmacología , Álcalis/farmacología , Antibacterianos/farmacología , Cloro/farmacología , Frío , Etanol/farmacología , Calor , Humanos , Lactante , Modelos Lineales , Viabilidad MicrobianaRESUMEN
This study determined the effect of acid, alkaline, chlorine, and ethanol stresses on the thermal inactivation of Enterobacter sakazakii in infant milk formula. Unstressed or stressed cells were mixed with reconstituted powdered infant milk formula (PIMF) at temperatures between 52 and 58 degrees C for various time periods or mixed with PIMF prior to reconstitution with hot water between 50 and 100 degrees C. D- and z-values were determined using liner regression analysis. In general, detergent and sanitizer stresses decreased the thermal resistance of E. sakazakii in infant milk formula. The results of this study may be of use to regulatory agencies, manufacturers, and infant caregivers to design heating processes to eliminate E. sakazakii.