Microbial Containment in Conventional Fermentation Processes.
Martinez-K; Sheehy-J; Jones-J; Cusick-L
Results of a survey of microbial containment in enzyme fermentation processes were summarized. Approximately 200 microbial air samples were collected at potential emission sites including the laboratory, inoculum tank, fermentation tank, and filtering operation at three enzyme manufacturing facilities. Sample concentrations around unit processes were compared with background concentrations in order to evaluate the extent of microorganism release from each process. Microbial concentrations varied from facility to facility depending on the type of microorganism used in production and the type of process equipment. For example, total microorganism concentrations up to 8620 colony forming units per cubic meter (cfu/m3) were found at a filter press in a solid liquid separation process at one facility. The major strain was the production microorganism. In a second facility, microorganism concentrations of 345cfu/m3 were found at a rotary vacuum drum filter equipped with local exhaust ventilation; however, less than 10 percent of the sample was the production strain. At the third facility, microorganism concentrations up to 875cfu/m3, including a significant amount of the production strain, were found at the centrifuge. These were less than expected due to engineering controls such as process enclosure and local exhaust ventilation being in place. The authors conclude that in enzyme production facilities, engineering controls are needed on filters, centrifuges, agitator shafts, and manual sampling ports. These should include enclosure or isolation where possible. Local exhaust ventilation is a viable alternative. Proper and safe work practices are also important.
NIOSH-Author; Air-sampling; Microorganisms; Industrial-hygiene; Control-methods; Exhaust-ventilation; Air-contamination; Occupational-exposure; Emission-sources;
The Changing Nature of Work and Workforce, Proceedings of the Third Joint US-Finnish Science Symposium, Frankfort, Kentucky, October 22-24, 1986, NIOSH, Cincinnati, Ohio