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A common fungus found in compost and in soil, hay, wood, and'foliage is Aspergillus fumigatus. Results of recent studies found a large percentage of compost workers tested positive for nose and throat cultures of Aspergillus fumigatus. In susceptible individuals, Aspergillus fumigatus can inhabit the lungs and form fungal infections. Spores can either be inhaled or can enter the body through cuts and abrasions in the skin. Composting promotes the growth of Aspergillus fumigatus since it is a thermophilic fungi (thermophilic organisms grow at high temperatures). Toward the end of the composting process, when the compost is cooling down and becoming drier, Aspergillus fumigatus may exist in large numbers. It's spores are readily dispersed from dry and dusty compost piles. While it is found everywhere in the environment, high levels of spores have been isolated from yard waste compost. Aspergillus fumigatus can utilize cellulose as its sole carbon and energy source and can therefore also thrive in wood chip piles found at many yard and sewage sludge compost sites. Control Destruction of most pathogens is achieved by the high temperatures (1220-1400F) that occur during the composting process. Figure 20 illustrates the 10 10 4 0 10 20 00 TIME. MINUTES relationship between time, temperature and survival of several pathogens. In addition to high temperatures, the generation of ammonia during composting could destroy viruses and other pathogens (ammonia has been shown to destroy polio virus)." Another pathogen control mechanism is the production of a well stabilized pile. A. well decomposed compost will not support recolonization as the food supply for the pathogens is gone. In order to ensure pathogen destruction, it is critical to expose all the composting material to the high inner temperatures. In the windrow method, the areas of lower temperature (outer areas), must be turned in and mixed with internal areas of higher temperature. When the compost is not turned, as in aerated static piles, cold zones and pockets may occur. It is therefore advisable to also turn the aerated static piles in order to thoroughly mix all the material. Clumps of composting material must also be broken up so they will not heat sufficiently. Worker Health/Safety The health of employees at a compost facility is a concern. The risk of infection in healthy individuals �� ab•c z 4 M o e 2 6]•C x � 4 o o� b4•C a m W o'b 10 e. e.Imo,,.xb Em M01. 10 00 00 60 TIME. MUTE' TIME, NOUNS Figure 20, Heat inactivation of coliform bacteria, Samonella Enteritidis, and Ascaris ova in composting sludge. Compost Engineering: Principals and Practice. Robert T. Haug, Ann Arbor, Michigan, Ann Arbor Science Publishers. 1980. IV-3