Five Principles to “Good Laboratory Selecting Practice (GLSP)"

Many microbiological testing laboratories reside within and just out side the borders of South Africa, forty-six registered laboratories to be precise. Like our rainbow nation, they vary in size, expertise, geographic location and service level. One could go as far as describing them as THE GOOD, THE BAD and THE UGLY!

As a food manufacturer, your primary function is to produce safe and wholesome food. Lower on your list of priorities is thetesting your products to meet requirements of your customers, local authorities or your basic commitment to your food safetyprogramme. Fuelled by your minimal knowledge of the laboratory industry, how do you begin selecting a laboratory? Wheredo you start? What questions do you ask? What criteria should benchmark your choice and which lab can actually meet yourtesting requirements?

If you find yourself in this scenario, the five principles (GLSP) to selecting a microbiological laboratory shall allow you tounderstand the microscopic world of your products. By following these basic steps, the laboratory you select shall guide youthrough this world.

Principle 1: Accredited – to be or not to be?

What is Accreditation?

The South African National Accreditation System (SANAS)* is recognised by the South African Government as the singleNational Accreditation Body that gives formal recognition that Laboratories are competent to carry out specific tasks (SANS17025). The global trend is towards a free market with no economic trade barriers, allowing for free movement of goods andinterchange of services. Such a situation can only be consummated when technical barriers to trade are also eliminated. Forthis to occur the trading countries must have confidence in the quality and environmental systems, personnel and productcertification and inspection systems as well as the measurements and tests conducted by each other.

The World Trade Organisation and the European Union (EU) both have noted that the lack of acceptance of test results andcertification, are the most significant non-tariff barriers to trade. Accreditation of laboratories using common standards andpractices is seen as the most effective way of defeating these barriers. To this end major trading countries have establishedindependent, and internationally credible accreditation bodies. At the apex of the world accreditation pyramid is theInternational Laboratory Accreditation Cooperation (ILAC), and the International Accreditation Forum (IAF), both of whichSANAS is a member (Reference:

Using an accredited laboratory assures you that:

  • Laboratories that are competent to carry out specific tasks
  • Laboratories across and between countries that use common and accepted standards and practices
  • Trading countries to which you may be supplying your product have confidence in the measurements and tests
    conducted by each other

How do I select an accredited laboratory?

  • Visit
  • Select tab “Accredited facilities”
  • Scroll down to and select “Directory of accredited facilities”
  • Select “Testing Laboratories”
    Laboratory No.
  • In the field “Search Testing Laboratories” select and fill in one of the following requirements or simply select the
    laboratory of choice from the list provided
  • Select the laboratory number e.g. T0001 and you will de directed to the laboratory’s accreditation schedule
    authorised by SANAS

Interpretation of an accredited laboratory

It is important to remember, however, that if a laboratory is accredited, it does not mean that it is accredited for the tests that you may require to be performed on your product and furthermore, that you need not visit and/or inspect your selected
lab just because it is accredited. This leads us to steps two and three.

.... Principle 1: Select an accredited laboratory (SANS 17025).

Principle 2: Your selected laboratory – to visit or not to visit?

It is the opinion of many excellent scientists out there, that simply basing your choice of laboratory on a list provided on theSANAS website, is not GLSP. All audits on accredited facilities are conducted strictly in accordance with guideline documentSANS 17025. However, a visit/inspection of your selected laboratory is a suggestion, as a book (or a lab in this case) can bejudged by its cover. One does not need to be an expert in laboratory etiquette, as general housekeeping, staff pride, basicupkeep of the laboratory and eagerness to inform on and show you the well-maintained quality procedures of the laboratory,are sufficient to secure your confidence in the laboratory.

If it is deemed necessary to audit your selected laboratory, ensure that the person conducting the audit is qualified toperform such an audit and is at least familiar with SANS 17025 or Good Laboratory Practice (GLP). It can be quite frustratingfor a microbiological laboratory to be audited by a nuclear physicist!

....Principle 2: Visit/inspect your selected laboratory.

Principle 3: Accreditation schedule – accredited for the tests you require or not?

Are the tests you require accredited in the laboratory you have selected? It is often taken for granted that if the laboratory isaccredited that all the tests it conducts are accredited too – NOT!The accreditation schedule, or commonly referred to an accreditation certificate, lists all the test methods that the laboratoryis accredited for. Thus, if your product requires ten different tests, ensure that the methods for these tests are all accredited.This leads us to the next criteria, cost

.....Principle 3: Laboratory methods accredited.

Principle 4: Cost of analyses – to budget or not to budget?

So you have selected a SANAS accredited laboratory that has all 25 methods that you require for your products to be tested,now you need to request a quotation from this laboratory. You need to provide the laboratory with your sample numbers andtesting frequency (testing schedule), if you have one. If you do not have one, refer to principle 5. This will enable thelaboratory to provide you will a discount structure based on your volumes.

Microbiological testing is always seen as money that was never included in the cost of manufacturing the product, so anymoney spent on such testing is always seen as a grudge purchase. Let’s put this into perspective: you have 10 000 cookedhams in 150 retail stores of a giant retailer across Gauteng and the retailer randomly selected your product to be tested. Theresults reveal E.coli at levels not fit for human consumption and the presence of Listeria monoctogenes. The retailer thenretests 20 additional samples from different stores, which confirm the initial tests, and then ask YOU for your test reports forthis product. YOU DID NOT TEST! The retailer recalls all products in store and all costs including all the testing are passed overto you. Compare this cost to the R 500.00 sample testing cost....and what about your reputation...PRICELESS!

This was just an example of what can occur should you not test according to an approved testing schedule, but this is also notan excuse for the laboratory to charge you exorbitant fees per test because you need to test. Here are a few considerations totake into account when you receive a quotation from a laboratory where the average test cost is R50.00 – R150.00:

  • Preparation of media for your test
  • Quality control of your media and laboratory for your test
  • Testing of the product by a qualified microbiologist
  • Incubation of your test as microorganisms can take up to 7 days to grow
  • Primary results and interpretation
  • Secondary testing (follow up) should the method require it
  • Test results calculations
  • Reporting of results (Laboratory report)
  • Transmission of your report to you via email/fax

Every step above is labour intensive and generally pricing fails to take the following into consideration:

  • Duplicate testing as required by the method
  • Imported media and consumables that is sensitive to currency fluctuation
  • QC checks by qualified personal at each step of the method to ensure that you get the result that is representative of the sample submitted

So why are microbiological tests always regarded as expensive? If all considerations were included in each quoted price,microbiological testing would not be affordable - especially if you tested every product. YOU DO NOT HAVE TO TEST EVERYPRODUCT OF EVERY BATCH OF EVERY DAY! Take the following into consideration when budgeting your microbiological testing:

  • Draw up a testing schedule to cover testing of all your product lines over a fixed time period e.g. 3 months
  • The testing schedule should cycle over a time period i.e. after 3 months the testing should begin again and so forth - this will enable sample testing to be repeated over different seasons, manufacturing cycles and any other variables.
  • Retests – not all results will come back favourably.
  • Never base you testing budget on the cost of the tests. Your cost should be calculated on your testing schedule.

Always try and get at least three quotations, so that you can see that most of the laboratories are within the same ballparkpricing, however, it is the service that you get with quotation that may lead you to your preferred laboratory. Principle 5 will help you with this.

....Principle 4: Budget testing in accordance with a testing programme.

Principle 5: Service – good or not?

RECAP: you have selected a SANAS accredited laboratory and you have visited/audited it. All the methods you require areaccredited and your quotation comfortably allows you to test all your products as per your testing schedule, so what more doyou need from your laboratory? Service?These basic requirements should be met by your selected laboratory and generally you only encounter them during or aftertesting has been completed. You can use these as guidelines as the final principle in your choice of laboratory according to GLSP:

  • Testing turn around, what to consider?
    • How long does a test take? Remember conventional plating methods take a minimum of 24 hours from time
    • of testing for some bacteria and up to 5 days for some yeast and mould species to grow. Some rapid
    • methods are available that can considerably reduce these times, but come at premium and sometimes at
    • expense of inconsistent and unreliable results.
    • Don’t forget to take counting, follow up testing, result calculation and report writing into account. This can
    • add another few hours or days onto the results.
  • Test report included in cost of analyses.
  • Accurate and reliable results – this can only be proven by testing between laboratories or proof of the laboratory’s proficiency testing scheme.
  • Discussing of results: a SANAS accredited laboratory is not permitted to interpret the results for you. Approved personnel can simply advise you on the results and what they mean in relation to the specification. Final decisions relating to the results and product are at your discretion as the results are only a reflection of that sample that was
  • Some laboratories go that extra mile by alerting you to out of specification results e.g. Presence of pathogens.

....Principle 5: Good service.

Congratulations you have selected a microbiological laboratory that meets all the principles of GOOD LABORATORY SELECTINGPRACTICE.

However, it is only through experience that you can determine whether it meets your requirements. Is yourlaboratory good in practice or just on the paper they quoted you on? Remember small steps and you will MAKE SENSE OUT OF MICRO....

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