Journal article
Water Diffusion from a Bacterial Cell in Low-Moisture Foods
Journal of food science, Vol.81(9), pp.R2129-R2134
09/2016
Handle:
https://hdl.handle.net/2376/115888
PMID: 27505687
Abstract
We used a Fick's unsteady state diffusion equation to estimate the time required for a single spherical shaped bacterium (assuming Enterococcus faecium as the target microorganism) in low-moisture foods to equilibrate with the environment. We generated water sorption isotherms of freeze-dried E. faecium. The water activity of bacterial cells at given water content increased considerably as temperature increased from 20 to 80 °C, as observed in the sorption isotherms of bacterial cells. When the water vapor diffusion coefficient was assumed as between 10(-12) and 10(-10) m(2) /s for bacterial cells, the predicted equilibration times (teq ) ranged from 8.24×10(-4) to 8.24×10(-2) s. Considering a cell membrane barrier with a lower water diffusion coefficient (10(-15) m(2) /s) around the bacterial cell with a water diffusion coefficient of 10(-12) m(2) /s, the teq predicted using COMSOL Multiphysics program was 3.8×10(-1) s. This result suggests that a single bacterium equilibrates rapidly (within seconds) with change in environmental humidity and temperature.
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Details
- Title
- Water Diffusion from a Bacterial Cell in Low-Moisture Foods
- Creators
- Roopesh M Syamaladevi - Dept. of Agricultural, Food and Nutritional Science, Univ. of Alberta, Edmonton, Alberta, Canada, T6G 2P5. syamalad@ualberta.caJuming Tang - Biological Systems Engineering Dept, Washington State Univ, P.O Box 646120, Pullman, Wash, 99164-6120, U.S.A. jtang@wsu.eduQingPing Zhong - College of Food Science, South China Agricultural Univ, Tianhe, Guangzhou, 510642, P. R. China
- Publication Details
- Journal of food science, Vol.81(9), pp.R2129-R2134
- Academic Unit
- Biological Systems Engineering, Department of
- Publisher
- United States
- Identifiers
- 99900547742601842
- Language
- English
- Resource Type
- Journal article