sentences:  Organic acids produced by microbes, in particular fungi, can corrode steel, glass and plastic.Furthermore, because of the increase in exposure to radiation on a spacecraft, there are likely to be more microbial mutations.Because of the potential for microbes to cause infection in the astronauts and to be able to degrade various components that may be vital for the functioning of the spacecraft, the risks must be assessed and, where appropriate, manage the levels of microbial growth controlled by the use of good astronautical hygiene.