Testing the performance of microbiological safety cabinets used in microbiology laboratories in South Korea

Aims: To test a performance of the microbiological safety cabinets (MSCs) according to the type of MSCs in microbial laboratories. Methods and Results: Tests were carried out to assess the performance of 31 MSCs in 14 different facilities, including six different biological test laboratories in six hospitals and eight different laboratories in three universities. The following tests were performed on the MSCs: the downflow test, intake velocity test, high‐efficiency particulate air filter leak test and the airflow smoke pattern test. These performance tests were carried out in accordance with the standard procedures. Only 23% of Class II A1 (8), A2 (19) and unknown MSCs (4) passed these performance tests. The main reasons for the failure of MSCs were inappropriate intake velocity (65%), leakage in the HEPA filter sealing (50%), unbalanced airflow smoke pattern in the cabinets (39%) and inappropriate downflow (27%). Conclusions: This study showed that routine checks of MSCs are important to detect and strengthen the weak spots that frequently develop, as observed during the evaluation of the MSCs of various institutions. Significance and Impact of the Study: Routine evaluation and maintenance of MSCs are critical for optimizing performance.     

Evaluation of laminar flow microbiological safety cabinets

The microbiological control efficiency of two class 100 laminar down-flow hoods was determined by using aerosols of Bacillus subtilis var. niger spores. The first unit challenged utilized a slanted eyelid to partially enclose the front work opening. This hood showed nearly perfect control of ambient organisms in the work area. It also gave a 10(6) or greater drop in the number of organisms passing out of the exhaust system. However, when the interior work area of the hood was challenged, significant numbers of spores penetrated the air barrier and escaped into the ambient air. A redesigned laminar flow hood was built incorporating a vertical eyelid and a reduced opening to the work area. This hood showed the same excellent characteristics for controlling ambient contamination. Exhaust system leakage was also extremely low. Air barrier efficiency for the newer hood was increased with lower amounts of spore penetration into the ambient air.     

Biological safety in virological field with special considerations on class II biological safety cabinets

The most critical point for the biosafety is not sophisticated devices or facilities, but education of workers and their compliance to the regulation. Appropriate devices should be carefully selected in the introduction of new devices, and they should be properly maintained. The class II biosafety cabinet is one of the delicate safety equipments. It should be kept adequately maintained throughout the lifetime of the cabinet to insure safety of the laboratory. For the maintenance, appropriate measuring equipments should be used by trained technicians. The recently enforced law for control of recombinant DNA researches should be applied for the handling of pathogens even in non-recombinant DNA researches after proper modifications.     

Continued successful operation of open-fronted microbiological safety cabinets in a force-ventilated laboratory

R.W. OSBORNE AND T.A. DURKIN. 1991. The considerable refinements necessary to enable Class I and II microbiological safety cabinets to operate in a force-ventilated laboratory and to meet appropriate safety criteria have been reported previously. The continued successful operation of such cabinets without a deterioration of operator protection is described. The performance of two Class II units, one meeting and one failing the current British Standard applied to four head KI-Discus testing, is compared and discussed. In addition, some further potential difficulties within the environment, which could compromise cabinet containment, are highlighted.     

Continued successful operation of open-fronted microbiological safety cabinets in a force-ventilated laboratory.

The considerable refinements necessary to enable Class I and II microbiological safety cabinets to operate in a force-ventilated laboratory and to meet appropriate safety criteria have been reported previously. The continued successful operation of such cabinets without a deterioration of operator protection is described. The performance of two Class II units, one meeting and one failing the current British Standard applied to four head KI-discus testing, is compared and discussed. In addition, some further potential difficulties within the environment, which could compromise cabinet containment, are highlighted.     

'Containment'—recent developments and BS 5726-1992 (microbiological safety cabinets)

A recent resolution of the Parliamentary Assembly of Europe (No. 986–1992) emphasizes that technical innovation is an important and continuing feature of modern society and that it will act as the driving force in commercial and industrial competition for a long while to come. The public draws substantial benefits from this technological progress but has also developed a keen awareness of the supposed effects of certain technologies on the ethical values on which society is based, on health and on the environment.
In this context, the issue of risks (particularly those present in certain new technologies) becomes more complex. Despite a general improvement in safety levels and a substantial reduction in traditional risks, new types of risks, far more difficult to calculate and predict, are emerging. This is especially true in the chemical, pharmaceutical and biotechnology industries where these difficulties have been recognized and where safe systems of work and equipment are therefore being developed that can effectively contain potentially hazardous material.
Of particular significance over the last 10 years in this area has been the marked improvement in the design and performance of safety cabinets and related containment systems for microbiological use. In the UK this has been due to a number of factors including the implementation of the requirements of BS 5726 1979 (Microbiological safety cabinets) (Anon. 1979) which have been complimentary to the COSHH (Control of Substances Hazardous to Health) Regulations (Anon. 1988) which themselves reinforced the Health and Safety at Work Act (Anon. 1974). Taken together, this framework has been responsible for significant improvements to the manufacturing technologies for safety systems, the management of containment systems within laboratories and the awareness by users of the functional requirements that all containment systems must now have.     

T1 bacteriophage as an indicator for decontamination of laminar-flow biological safety cabinets.

Type 1 coliphage dried onto a glass surface was used as an indicator to monitor decontamination of biological safety cabinets. When desiccated virus was treated with formaldehyde vapor (5,000 or 10,000 ppm) adjusted to 70 to 90% relative humidity immediately before testing, viral inactivation was slow for the first 50 min but then accelerated, being complete in the next 10 min. However, when virus was incubated in an atmosphere containing 70% humidity for 1 h before formaldehyde was added, inactivation was complete within 3 min, indicating that careful attention must be paid to relative humidity in decontamination of safety cabinets.     

Survey of safety and health care in British medical laboratories.

A retrospective postal survey of 24 000 medical laboratory workers in England, Wales, and Scotland showed highly variable standards of safety and health care. Pre-employment health screening was offered to two-thirds of employees, the physicians being the least likely to be examined (15%). Scottish laboratories provided better safety control than English and Welsh laboratories, while Public Health Service Laboratories had a better record than National Health Service establishments. Mouth pipetting is still practised in 65% of English and Welsh laboratories, and the use of protective clothing is rarely compulsory. The servicing of safety cabinets is often inadequate. Known and suspected carcinogens are still apparently used in a few laboratories (2-10%). In view of the wide variation in standards among laboratories, urgent consideration should be given to establishing regulations for codes of safe practice rather than relying merely on recommendations as at present.     

Performance of open-fronted microbiological safety cabinets: the value of operator protection tests during routine servicing

The performance of class I and II microbiological safety cabinets over 7 years, employed in a force-ventilated containment level 3 (CL-3) laboratory, is described. Operator Protection (OP) provided by the cabinets, assessed by still and latterly limited 'in-use' KI-Discus tests, showed no overall deterioration during the review period. Comparisons show that a selected class II unit, but not a second, and a new class II MSC in a recently commissioned, similar CL-3 facility, provide the same order of OP as a class I cabinet. From the experiences described, it is strongly recommended that OP tests (OPTs) should be part of the routine servicing regime to ensure that cabinets meet required performance levels, and additionally to allow detection and rectification of poor containment, particularly where induced by environmental factors. The value of OPTs is discussed with reference to certain national standards.     

Flyway structure in the circumpolar greater white‐fronted goose

Dispersal and migratory behavior are influential factors in determining how genetic diversity is distributed across the landscape. In migratory species, genetic structure can be promoted via several mechanisms including fidelity to distinct migratory routes. Particularly within North America, waterfowl management units have been delineated according to distinct longitudinal migratory flyways supported by banding data and other direct evidence. The greater white‐fronted goose (Anser albifrons) is a migratory waterfowl species with a largely circumpolar distribution consisting of up to six subspecies roughly corresponding to phenotypic variation. We examined the rangewide population genetic structure of greater white‐fronted geese using mtDNA control region sequence data and microsatellite loci from 23 locales across North America and Eurasia. We found significant differentiation in mtDNA between sampling locales with flyway delineation explaining a significant portion of the observed genetic variation (~12%). This is concordant with band recovery data which shows little interflyway or intercontinental movements. However, microsatellite loci revealed little genetic structure suggesting a panmictic population across most of the Arctic. As with many high‐latitude species, Beringia appears to have played a role in the diversification of this species. A common Beringian origin of North America and Asian populations and a recent divergence could at least partly explain the general lack of structure at nuclear markers. Further, our results do not provide strong support for the various taxonomic proposals for this species except for supporting the distinctness of two isolated breeding populations within Cook Inlet, Alaska (A. a. elgasi) and Greenland (A. a. flavirostris), consistent with their subspecies status.     

Cultivation of the lichenParmotrema tinctorum in growth cabinets

The growth of lichens in the field is slow and their cultivation is generally thought to be difficult. We studied the effects of environmental conditions and culture solutions on the growth of a lichen, and found that growth ofParmotrema tinctorum (Nyl.) Hale in growth cabinets was possible. The thallus area increased by about 20% monthly when the lichen was soaked in a culture solution for 90 min every four days and then grown at 100% relative humidity when the temperature in the growth cabinet was 20C and illumination was at 12 W/m² for 16 hr daily.