Scanning electron micrograph (SEM) of Bifidobacterium bifidum. Bifidobacterium bifidum is a member of the large family of probiotic ("friendly") bifidobacteria which are present in mammalian gastrointestinal systems including humans and cattle, where they suppress pathogenic microorganisms. Some are also present in the intestines of poultry. They are used by the dairy industry in addition to lactobacilli and lactococci to make yogurt and are also part of medicinal supplements. (Microscope magnification: 16,000x, image width: 8.0 micrometers.)