Interpretation of allergen results can be tricky. Yr problem is that you have a specific, positive, reported level.
For example ex-Neogen handbook -
14. Why are the Alert and Reveal test kits set at 5 ppm and 10 ppm?
Because regulators have not set actual thresholds for allergens, the food industry has taken a
proactive approach of self-governance and chosen these levels. They are relevant by minimizing
risk to the consumer, without going to “zero tolerance” as a threshold.
15. What does the term “limit of detection” mean? Is it different than “limit of quantitation”?
A test kit’s limit of quantitation (LOQ) refers to the lowest point that its results are quantifiable. As
a general rule, ELISAs identify this as the first non-zero control in that kit, which is the 2.5 ppm
control in Neogen’s test kits. The limit of detection (LOD) is the lowest point at which a result can
be considered above background noise. A LOD is determined as the mean of 10 evaluations of a
known negative sample, plus two standard deviations. However, results greater than the LOD but
less than the LOQ are analytically valid for qualitative purposes only.
16. should a sample that tests below 5 ppm on an Alert kit be called “negative”?
No. As indicated above, the 5 ppm level has been established and generally recognized by the food
industry as an indicator of risk associated with testing. However, levels below 5 ppm do not mean
the sample is negative, as levels between the detection limit and 5 ppm may still be allergenic.
More appropriate would be the phrase: “Below limit of detection (BLD)”.
17. What are the allergen kits detecting and how is it reported?
Each specific test kit detects the presence of residue from the allergenic food of concern. Each test
reports the ppm value to the total allergenic food. For example: peanut results are reported as ppm
of total peanut, as opposed to protein only. See Appendix A for specific allergen information. See
Appendix D for converting allergenic food results to protein results.
18. Are all manufacturers’ food allergen test kits reporting on the same scale?
No, some manufacturers report results in ppm protein, others in ppm total allergenic food.
Neogen’s Veratox and Alert tests report as the ppm of total allergenic food. Those who prefer to
convert their results from ppm total allergenic food to ppm allergenic protein can do so based on
average protein content of these foods. For example, nonfat dried milk (NFDM) contains approxi-
mately 35% protein. Therefore, a 5 ppm total milk on the Veratox for Total Milk Allergen test would
be approximately 1.75 ppm milk protein. Peanut is approximately 26% protein, so 5 ppm Veratox
for Peanut results would convert to 1.3 ppm protein. See Appendix D for converting allergenic food
results to protein results.
I am no expert in this area so this is speculation but I think the above means that if the chosen methodology used for yr sample had been "set" at 5ppm limit, yr result would maybe have been reported as "not detected" (ie < 5ppm). Seems method used in yr case was "super"-sensitive which is presumably preferable from a safety POV
Also see Note 18.
PS - here are some methods which claim LOD 0.5 - 1 ppm of peanut so I guess highly sensitive methods do exist for this item particularly in view of its potent allergenic characteristics.
I sort of conceptually agree with Trubertq but this demands yr also proving the possibility of non detection. Whether UK would happily accept yr product/data as is since combined with inclusion of peanut caveat on label is "problematic".
JFI, here is Neogen's suggested approach to controlling an analogous peanut process to yr own.