Test organisms were chosen according to set criteria. All bacteria have environmental origin and are not true pathogens. Genus Bacillus
includes common airborne bacteria that can produce very tolerant cell forms called spores. Micrococcus
is frequently found in air sampling because it produces pigments that protect it against the radiation of sunshine. Escherichia
is another common type of bacterium, both in aquatic environments and in the human colon, serving as an indicator organism for faecal pollution.
Among the fungi chosen were Penicillium
chosen – the former because of its universal distribution as an actively sporulating mould, the latter as an
internationally accepted yeast species for various types of testing.
||Type of organism
||Gram-positive, aerobic, sporulating, rod-shaped bacterium
||Gram-negative, facultatively anaerobic, rod-shaped bacterium
||Gram-positive, aerobic, pigmented, cocci-shaped bacterium
||A common mould
||A common yeast
1 Strain codes of culture collection by ATCC (E.coli) or by VTT (other organisms)
2 TYGA = Tryptone Yeast Extract Glucose Agar, MEA = Malt Extract Agar