The medical and epidemiologic effects on workers of the levels of airborne Thermoactinomyces Spp. spores present in Australian raw sugar mills.

The objectives of the study were to determine whether there was a significant risk of members of the work force of raw sugar mills developing bagassosis. Airborne Thermoactinomyces sacchari spores were measured to determine whether they were sufficient to cause acute bagassosis, and whether there was any evidence of previous exposure to sufficient airborne T. sacchari spores to cause the development of chronic bagassosis in any of the work force. Monitoring of total airborne bacteria spore concentrations was undertaken in and around two cane sugar mills before, during, and after the 1992 cane processing season. Viable airborne bacteria counts were also obtained to confirm the presence of Thermoactinomyces sacchari. Area or zone samples at various sites around the mills and personal breathing zone samples from selected workers were obtained. The results showed that the total airborne bacteria spore count was lower than similar counts reported in other industries, such as cotton milling and wood chip handling, during normal operations. It was also found that the airborne counts during specific activities that generated higher than usual airborne spore levels were lower than expected from literature reports of handling similar material. Complementary medical examination of the entire full-time work forces of the two mills was carried out on a number of occasions during 1992. The medical data showed that no cases of acute bagassosis were detected, and that there was no evidence of the development of chronic bagassosis in any members of the work forces of either mill. Therefore, there is no significant risk of workers in the Australian sugar industry developing bagassosis.