Food Supplements: moving from the ‘Wild West’ towards quality and compliance
In this unique PT sample, AXIO has provided a means for laboratories to assess the compliance of a supplement product with the claims or information provided on the label. Proficiency testing can help laboratories assess compliance with labelling
Sample
Quantity Supplied as
Target Analyte(s)
PT-PH-21 Potency of multielement
15g
Multielement supplement
Calcium; Zinc; Magnesium; Copper; Manganese; Potassium; Iron; Total Chromium; Selenium; Compliance with labelling.
It challenges laboratories to decide whether they would consider the product compliant or not, based on the label provided in the instruction sheet, their obtained testing results (including the uncertainty of measurement) and the guidance documents. The PT summary results for two analytes, zinc and potassium (respectively labelled at 5.882 and 0.046 mg/g on the provided label), are shown below.
Standard deviation for proficiency assessment (SDPA)
Uncertainty of Assigned Value
Satisfactory Range 4.78 to 6.89 0.34 to 1.06
Analyte
Unit
Assigned Value
Exp. SDPA
Zinc
mg/g 5.84
0.213 0.072
0.482 0.163
0.527 0.178
Potassium mg/g 0.70
The satisfactory range in a proficiency testing exercise is derived from the Assigned Value and the standard deviation for proficiency assessment (SDPA). In many cases the satisfactory range for proficiency testing is defined as the assigned value +/- 2 times the SDPA. The measurement uncertainty of the assigned value is included in the estimation of the satisfactory range. The EU guidance document on the control of compliance for minerals in food supplements specifies lower and upper tolerances (including the measurement of uncertainty for the analytical result) of -20% and +45% respectively.
PROFICIENCY TESTING
LABEL
Acceptable range based on the guidance document of -20%, +45%
Satisfactory range in the PT
Assigned value (AV)
Label (mg per g)
Element
Lower limit
Upper limit
Lower limit
Upper limit
5.84
4.78 0.34
6.89 1.06
5.882 0.027
4.706 0.022
8.529 0.039
Zinc
Potassium 0.7
Zinc concentration was compliant with the labelling, as the measured result and its uncertainty overlap significantly with the label value and its tolerances, while the potassium concentration was not.
9
Assigned Value Min/Max range
8
7
6
5
4
3
2
1
0
Zn Data
Zn Label
K Data
K Label
6
Made with FlippingBook Digital Proposal Creator