Cell size of various lactic acid bacteria as determined by scanning electron microscope and image analysis

Abstract

Cells from 48 pure lactic acid bacterial strains from the ACA-DC collection were studied under the scanning electron microscope (SEM) and the images were photographed and processed with an Image Analysis software. The diameters of several cocci and the lengths and widths of several lactobacilli strains were measured, then the size parameters were statistically analyzed by variance analysis. Significant differences were found between the cell sizes of the cocci strains (Streptococcus 1.07 to 1.21 μm, Enterococcus 0.87 to 1.01 μm, Lactococcus 0.75 to 0.95 μm), but not between lengths and widths of the bacilli strains because too high variations were found in the last measurements. © Inra/Elsevier, Paris.