Tecomak carries out biological sampling for a wide range of facilities including clean rooms, operating theatres, intensive care units and pharmaceutical production labs.

We use a range of techniques appropriate to the type of facility and the organisms being tested for. These include settle plates, contact plates and active air sampling techniques. This article describes these techniques in more detail.

With all these methods, it is essential that equipment is handled correctly to ensure accuracy. Items need to be stored in sterile conditions and packaging, and there must be no contamination introduced when unpacking, putting in place, on collection and transfer to incubator. Special protocols are required and operators need to be highly trained so that consistent results are achieved.

Tecomak has a team of professionally qualified technicians providing a full range of clean room testing and certification services. Our standards can be relied on, and we ensure full GMP and HTM 03-01 compliance.

Settle Plate Sampling

This method of biological sampling is used to test for airborne organisms such as mould and bacteria. It can tell you how much contamination is likely to be landing on surfaces within a given time period.

Regarded as a passive monitoring method, it involves using a settle plate, which is typically a Petri dish containing some type of agar jelly, such as malt extract agar (MEA). The type of settle plate chosen will often be specific to the organism being tested for, to allow that type of bacteria to grow especially well while others are inhibited.

During the testing process, the settle plate is left somewhere in the facility for a specific time period, then collected and incubated at a set temperature and for a set time. Once this has been done, a count is taken of the organisms on the plate. Putting plates in different locations within a room, such as right next to an air filter, can help to diagnose the source of organisms and show where they are most prevalent. The results can be compared to previous figures for the same facility, showing any changes over time, as well as to standards set by external bodies or the client’s own internal standards.

This method of testing isn’t suitable for areas where mould or bacteria is localised, such as around windows, and not airborne. It also cannot effectively test for levels of dead organisms, as these won’t multiply when incubated on a plate.

Contact Plate / Swab Sampling

When you need to test the levels of organisms on surfaces – ranging from work counters to handles, walls, floors and clothing – contact plate or swab sampling is a suitable method. It is also regarded as a “passive” technique, although somewhat more targeted than settle plates. Petri dishes are once again used for this type of biological sampling, with a medium appropriate to the organism being tested. First a swab is taken of the surface being tested, and then the swab is applied to the medium.

Alternatively, some contact plates are designed to be applied directly to surface and then removed – which helps to counteract differences in swabbing techniques.

The plate is incubated for a set time and in specific temperature conditions, as with the settle plate technique, before a count of organisms is taken. This method is used to test contamination on particular work areas or equipment, such as surgical instruments or food preparation areas.

The swabbing technique can affect the results, so it is important that this is done to protocol and consistently. This means of testing is most suitable when the likely source of contamination in the clean room or healthcare facility is through contact, rather than being airborne.

Active Air Sampling

This hi-tech method can be used to monitor levels of airborne micro-organisms as part of our clean room service. A Petri dish is placed at the top of the device, with appropriate careful handling as for other methods to avoid introducing any contamination. The device is then set running, and a set volume of air is pulled through the collector over a designated time period. The Petri dish is then removed, closed and incubated.

This method allows multiple tests to be made in a short amount of time, with a test possibly taking a couple of minutes, as opposed to a period of 30-60 minutes for a passive settle plate. An advantage of this is that it makes it easier to take multiple tests at different points within a facility, or in different conditions, for instance when the facility is at rest and when it is in use.

Tecomak’s Biological Sampling Expertise

Tecomak Environmental Services perform all types of biological sampling to suit the needs of the specific facility. Trained staff carry out testing to strict protocols, ensuring accuracy and consistency and comparability between tests.

We can carry out testing as part of verification for compliance and certification, or as ongoing monitoring for use by the facility owner. We also offer GMP training and support for staff working in this type of facility. Click on the link above to find out more about our professional testing services.