Safety in industrial microbiology

Industrial and research laboratories have a very strict set of guidelines to follow for microbiological work. Laboratory surfaces, such as floors, working surfaces and walls must be smooth and easy to clean. There must be a regular routine of cleaning and maintenance. Some areas are designed ‘clean zones’ where full protective clothing must be worn, and careful techniques used to avoid the escape of pathogens or the introduction of contaminating organisms into pure cultures. Often, laminar flow cabinets are used to create a sterile working area. These have air flow hoods which create a more negative air pressure within the cabinet than in the laboratory. This minimizes the chances of microorganisms being carried into the laboratory in air currents. The air flow hood filters all air entering and leaving the cabinet.

In recent years there have been concerns expressed about potential hazards in the use of genetically engineered organisms, particularly if they are realized into environment. Evidence to date shows that recombinant are no more dangerous than traditional ones. However, it is wise for research establishments and companies involved in biotechnology to be extremely careful and be aware of public concerns when designing production facilities.

Fermenters should be designed to keep contaminating organisms out and therefore they should also be effective in retaining any potential pathogens. There are design features on the fermenters, such as double mechanical seals on the agitator shafts and filters on the exhaust gas outlets to help ensure that is the case. The sampling outlets (ports) must be carefully designed to contain any spillage (tiny droplets of liquid in the air). Aerosols are a risk because they provide a moist, oxygen-rich environment which encourages the growth of microorganisms. Aerosol can be inhaled and so are an easy route of inflection. They can also spray microorganisms over a considerable distance where they can contaminate equipment and laboratory personal. All effluent from the fermenter and the washings from the cleaning process must be passed through a continuous sterilizer or into a large ‘kill tank where disinfectants are added to destroy any remaining microorganisms.

There may also be hazards involved in down-stream processing, that is the processes required to obtain the product from the contents of the fermenter. Care needs to be taken with heat exchangers to avoid freezing the culture fluid, which could result in thermal expansion and fracture of the exchanger. Centrifuges are notorious for producing aerosols. They must have an air-tight seal and all vents on them should be fitted with microbiological filters. All the equipment must be connected with high quality piping and all joints securely welded. It should be possible to sterilize the whole of the fermenter and downstream processing equipment, usually with steam under pressure.

Дата добавления: 2015-11-16