N.69 – TRIO.BAS Air Sampler Biological efficiency test according ISO 14698-1

TRIO

CMA – CENTRO DI MICROBIOLOGIA APPLICATA

Via Cusago 154 20019 Settimo Milanese

Laboratorio accreditato ACCREDIA n. 1087

Direttrice Dr Miriam Magrì

Biological efficiency testing of several active microbiological air samplers according ISO14698-1 in a dedicated microbial wind tunnel.

foto

ABSTRACT

The aim of this test was to assess the performances of different impactor microbial air samplers. Three different air samplers were compared: TRIO.BAS (Orum International),SAMPL’AIR, SAS Surface Air System (PBI-VWR). No significant difference in the efficiency was found between the 3 instruments. On the basis of their performances like unit sampling investment, simplicity of use, autonomy, portability, it was concluded the all the mentioned active impactors are suitable for routine microbial evaluation in controlled environments. The microbial wind tunnel was suitable for the performed tests.

INTRODUCTION

The testing of the microbiological quality of the air is important in areas like pharma, biotechnology, medical devices, food industries and operating theatres. The content of micro-organisms in these area must be under strict control to guarantee the safety for the staff and for the product in the interest of the customers, patients. To reach these goals an appropriate sampling devices has to be used.

THE ACTIVE MICROBIOLOGICAL AIR SAMPLERS

The most popular active microbiological air samplers are of impactor type, based on the principle described by Andersen in which air is aspirated through a perforated aspirating head with a pattern of small holes. The number of holes and their dimension are different according different producers. The produced air streams containing microbial particles are directed onto a sterile agar surface contained in a culture plate (Petri dish 90 mm or Contact plate 55 mm). At the end of aspirating cycle, the culture plates are removed and transferred to incubator. The viable organisms which produce visible colonies (CFU) are then counted and referred to a known volume of air.

The biological efficiency of a sampler is a measure of how it can collect micro-organisms on an agar plate in a way as micro-organisms will form a colony after incubation.

The biological efficiency is correlated to many factors (type of micro-organisms, their grow, type of aerosolization, relative humidity of the environment, volume and age of the used medium, the effect of jet velocity, nozzle size, and nozzle distance from the agar surface, etc,).

The bio-aerosol samplers  collecting viable particles onto agar plates have an average sampling efficiency of about 70%  over 3-4 microns particles.  About 90% of environmental microorganisms have a dimension over 5 microns.

A comparison of the collection efficiency of different microbial air samplers according to the study made by Shintani et al (2004) states that differences between air sampler performance may not be due to the inferiority of one sampler, but due to the inappropriate choice and volume of the collecting medium. It is therefore quite important the correct choose and preparation of the agar medium.

WIND TUNNEL FOR BIOAEROSOL TESTING

The performance evaluation of the active microbiological air samplers should be tested in a wind tunnel, under laminar flow, to standardize the operating parameters.

PURPOSE OF THIS DOCUMENT

The purpose of the test described in this paper was to evaluate the efficiency of a biological wind tunnel and compare the result of different active air samplers present on the market.

The biological wind tunnel produced by the company ORUM International (picture 1).

The tested active air samplers were. Sampl’air, SAS Surface Air System, TRIO.BAS (picture 2).

PROTOCOL

Micro-organism: Bacillus clausii Sanofi Lot 1359 – 11/2016. Evaluated and confirmed concentration 34.000.000 CFU/ml.

Nebulization: The culture was nebulized in front of the wind tunnel using the Safety Atomo 91701 nebulizer.

The test was performed in Safety Biological Cabinet “Faster” with sterile laminar flow (picture 1 ).

The used culture medium was the Plate Count Agar (PCA) according the UNI EN ISO 4833-2:2013/Cor.1:2014.

The culture plates were 90 mm Petri dish and 55 mm RODAC.

The aspirated volume of air was 100 litres of air.

The microbiological technique for the count in the laboratory was according the UNI EN ISO 4833-2:2013/Cor.1:2014.

Results

BIOLOGICAL EFFICIENCY TESTING OF SEVERAL ACTIVE MICROBIOLICAL AIR SAMPLER ACCORDING ISO14698-1

 

AIR SAMPLER

PLATES

VOLUME OF ASPIRATED AIR

CULTURE MEDIUM

METHOD

RESULTS 

CFU

DATE

 

TRIO.BAS MONO

Petri diam. 90 mm

100 lts

Plate Count Agar

UNI EN ISO 4833-2:2013/Cor.1:2014

300/ plate

20/23 July 2015

TRIO.BAS MONO

Petri diam. 90 mm

100 lts

Plate Count Agar 

UNI EN ISO 4833-2:2013/Cor.1:2014

300/plate

20/23 July 2015

TRIO,BAS

MONO

Petri diam.90 mm

100 lts

Plate Count Agar

UNI EN ISO 4833-2:2013/Cor.1:2014

230/ plate

20/23 July 2015

 

SAMPL’AIR 100

Petri diam. 90 mm

100 lts

Plate Count Agar 

UNI EN ISO 4833-2:2013/Cor.1:2014

220/plate

20/23 July 2015

SAMPL’AIR 100

Petri diam. 90 mm

100 lts

Plate Count Agar 

UNI EN ISO 4833-2:2013/Cor.1:2014

220 /plate

20/23 July 2015

SAMPL’AIR 100

Petri diam. 90 mm

100 lts

Plate Count Agar 

UNI EN ISO 4833-2:2013/Cor.1:2014

160/plate

20/23 July 2015

 

SAS 180

Contact plate

100 lts

 Plate Count Agar

UNI EN ISO 4833-2:2013/Cor.1:2014

160/plate

20/23 July 2015

SAS 180

Contact plate

100 lts

 Plate Count Agar

UNI EN ISO 4833-2:2013/Cor.1:2014

160/plate

20/23 July 2015

SAS 180

Contact plate

100 lts

 Plate Count Agar

UNI EN ISO 4833-2:2013/Cor.1:2014

160/plate

20/23 July 2015

CONCLUSIONS

The obtained results confirm that the tested microbiological wind tunnel is suitable for the efficiency evaluation of air samplers and that TRIO.BAS, Sampl’air and SAS 180  correspond to the requests according ISO14698-1 . On the basis of their performances like unit sampling investment, simplicity of use, autonomy, portability, it was concluded the all the mentioned active impactors are suitable for routine microbial evaluation in controlled environments.

 

REFERENCES

ISO 14698-1:2003 /2014

Cleanrooms and associated controlled environments — Biocontamination control — Part 1: General principles and methods

ISO 14698:2003 establishes the principles and basic methodology of a formal system of bio-contamination control (Formal System) for assessing and controlling bio-contamination when cleanroom technology is applied for that purpose. It specifies the methods required for monitoring risk zones in a consistent way and for applying control measures appropriate to the degree of risk involved. In zones where risk is low, it can be used for information.

ISO 4833-2:2013

Microbiology of the food chain – Horizontal method for the enumeration of microorganisms – Part 2: Colony count at 30 degrees C by the surface plating technique

 

ISO 4833-2:2013 specifies a horizontal method for enumeration of microorganisms that are able to grow and form colonies on the surface of a solid medium after aerobic incubation at 30 C. The method is applicable to:environmental samples in the area of food and feed production and food handling.

UNI EN ISO 4833-2:2013/Cor.1:2014 Microbiological technique for the colony count in the laboratory.

23 July 2015.