Image Analysis Based Quantification of Bacterial Volume Change with High Hydrostatic Pressure

Scanning electron microscopy (SEM) images of Staphylococcus aureus 485 and Escherichia coli O157:H7 933 were taken after pressure treatments at 200 to 400 MPa. Software developed for this purpose was used to analyze SEM images and to calculate the change in view area and volume of cells.

Journal of Food Science Logo Staphylococcus Aureus Escherichia coli O157:H7

Image Analysis Based Quantification of Bacterial Volume Change with High Hydrostatic Pressure

Mutlu Pilavtepe-Çelik, Murat O Balaban, Hami Alpas, A.E. Yousef
Vocational School of Ihsaniye, Kocaeli University, 41040, Izmit, Kocaeli, Turkey.
Journal of Food Science
(Impact Factor: 1.7).12/2008; 73(9):M423-9. DOI: 10.1111/j.1750-3841.2008.00947.x Source: PubMed3

ABSTRACT

Scanning electron microscopy (SEM) images of Staphylococcus aureus 485 and Escherichia coli O157:H7 933 were taken after pressure treatments at 200 to 400 MPa. Software developed for this purpose was used to analyze SEM images and to calculate the change in view area and volume of cells. Significant increase in average cell view area and volume for S. aureus 485 was observed in response to pressure treatment at 400 MPa. Cell view area for E. coli O157:H7 933 significantly increased at 325 MPa, the maximum pressure treatment tested against this pathogen. In contrast to S. aureus, cells of E. coli O157:H7 exhibited significant increase in average view area and volume at 200 MPa. The pressure-induced increase in these parameters may be attributed to modifications in membrane properties, for example, denaturation of membrane-bound proteins and pressure-induced phase transition of membrane lipid bilayer.