Confirming label claims
Supplement producers and retailers require comprehensive analytical capabilities to assess quality parameters and detect common contaminants. These analytical methods, whether they are chemical or microbiological, must be fit for purpose, and an established means of assessing their effectiveness is proficiency testing. PT is an essential quality tool for laboratories for a number of reasons, not least of which is that laboratories performing testing which is accredited to ISO/IEC 17025 are required to monitor their performance in comparison to other laboratories. PT involves the distribution of blind samples to participating laboratories, which then analyse the samples and submit their results to a PT provider. These results are evaluated using a performance assessment criteria described in ISO/IEC 17043 and ISO 13528, and feedback is provided to the laboratories, enabling them to identify any areas for improvement in their testing processes. Among the other benefits of PT is that laboratories taking part can receive test materials which are identical or highly similar to their routine samples, while participation also allows an accurate reflection of the accuracy and reliability of their test results, capabilities and resources to emerge. These capabilities encompass a range of factors including the variety of tests conducted, available methodologies, instrumentation, and overall competency. One of the most valued characteristics of PT is the independence of this evaluation: laboratories can, and should, routinely undertake many other forms of quality assurance, but PT is the only one where the ‘answer’ or desired result is not known by the laboratory beforehand. The need for proficiency testing
Dietary supplements, often derived from plant-based sources, vary naturally vary in composition. For example, St. John’s Wort, commonly used to treat cold and flu symptoms, shows significant changes in active ingredient levels depending on yearly growing conditions and harvest times [18]. It is therefore important that realistic tolerances, which account for this variability, can be applied to the nutritional labelling of these products. A manufacturer can compare the laboratory’s testing results with the theoretical composition of the product to determine their similarity. However, the next challenge lies in determining whether the product aligns with regulatory guidelines. The guidance documents below also set some clear rules on what is considered compliant or not: • In the EU: Guidance document for competent authorities for the control of compliance with EU Regulation (EU) No 1169/2011 of the European Parliament and of the Council of 25 October 2011 on the provision of food information to consumers (2012) [19]. • In the US: Code of Federal Regulation Title 21 (21 CFR 101.9(g)(3)) and (g)(4) [20].
Measurement uncertainty
To determine whether a measurement result aligns with a specification and demonstrates compliance with regulations, it is crucial to also consider the associated measurement uncertainty. The 2021 Eurachem guide Use of uncertainty information in compliance assessment [21] offers the following guidance on incorporating uncertainty when assessing compliance with specified limits: “ Any analytical measurement is subject to an uncertainty. In practice the uncertainty may arise from many possible sources, including (but not limited to), sampling, matrix effects, uncertainties of masses and volumetric equipment, approximations, etc. ” And: “An analytical measurement result is complete only when it is accompanied by a statement of the associated uncertainty.” [22]
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lgcstandards.com/AXIO
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