Scanning electron micrograph (SEM) of yogurt bacteria. Yogurt mixed bacterial starter culture consisting of Lactobacillus bulgaricus (blue), Streptococcus thermophilus (orange) and bifidobacteria (magenta). The bacteria have been assigned arbitrary colours. Yogurt is made in part through the fermenting action of these bacteria. Micr. magn. 16,000x, image width 7.0 um.