Human feces consist of digested food residues and bacteria of various kind, including the intestinal rod Escherichia coli. The large proportion of bacteria in human and animal feces makes it clear that the bacteria may by spread by various means from unwashed hands through contaminated water used for irrigation of field leaf vegetables such as spinach and lettuce. Enhanced SEM. Image width: 12.8 micrometers; magnification: 7810x if the images is printed 10 cm wide. By scanning electron microscopy.