Bacteria are single-celled microorganisms which can exist either as independent (free-living) organisms or as parasites (dependent upon another organism for life). They are about 0.5 to 2 micrometres in size. A grain of sand is 2 millimetres in size. This means you could fit 1000 bacterial cells into a single grain of sand. This means we can only see bacterial cells through the microscope.
Reading Time: 3 minutes Salmonella species are very similar to those of E.coli, if fact E.coli can be considered the big brother of Salmonella,