Targeting of Analytical Sampling - Avoiding the Echo-Chamber Trap
John Points, Consultant Analytical Scientist, UK, www.johnpoints.com/
This paper gives an approach to prioritisation of sampling and analytical testing when the only data you have available are trends in historical test results.
The pitfalls of relying purely upon trends in “positive” results are highlighted. Rather, an approach is recommended where trends are normalised where possible for trade volumes or for known biases in testing frequencies.
Some examples are shown, and some of the results are counter-intuitive. Issues with a relatively high incidence, as measured using this approach, include undeclared sulphites in dried apricots from Greece, USA, Uzbekistan and Pakistan (rather than from Turkey), aflatoxins in figs, nutmeg and pistachios (rather than in peanuts), and pesticide residues in goji berries.
The approach is particularly applicable to assessing the relative mycotoxin risk in the same product from different countries of origin. Again, the results can be counter-intuitive. Chinese peanuts have a significantly higher incidence of aflatoxins than those from the USA, but the reverse is true for pistachios.
Full Text of the paper