Impact of Sub-Inhibitory Water Activities on the UV-C and Desiccation Resistance of <i>Cronobacter sakazakii</i>

This study evaluated the effect of sub-inhibitory water activities on the survival of Cronobacter sakazakii under UV-C radiation and desiccation.One reference strain (C.sakazakii ATCC 51329) and one food isolate were cultured in trypticase soy broth adjusted to three water activity (a w ) levels (0.960, 0.970, 0.980) using either sodium chloride (NaCl) or glycerol for 24 h, and subsequently exposed to UV-C radiation, desiccation, or their combination.Growth and inactivation data were described using the Gompertz and Weibull models, respectively.Reduced water activity decreased growth rate and extended the lag phase in both strains.NaCl at low a w enhanced C. sakazakii resistance to UV-C, whereas glycerol at a w 0.960 increased sensitivity to desiccation.Trehalose was not detected under any conditions tested.This compatible solute, potentially produced during osmotic stress or desiccation to protect C. sakazakii's proteins and cell membranes and support its integrity and survival, did not accumulate.These findings highlight the role of solute type and water activity in shaping C. sakazakii stress responses, providing valuable insights for designing effective UV-C and desiccation-based treatments for contaminated foods and processing surfaces.