Problematic residue definition of Folpet

As of 26 August 2016, a new residue definition for the fungicide Folpet applies, which, in addition toFolpet also includes the metabolite phthalimide ("sum of folpet and phtalimide expressed as Folpet" Regulation (EU) 2016/156). The background is that Folpet may already be converted into the degradation product phthalimide in the plant.

However, it turns out that not every phthalimide finding can be explained by the use of Folpet as a pesticide, but that other sources are possible.

The laboratory expert group relana® could evidence by analysing several hundred data sets gathering experience from the laboratories, that phthalimide is often formed regardless of the presence of folpet.

It forms out of the ubiquitous environmental chemicals "phthalic acid" and "phthalic anhydride" in reactions with primary amino groups commonly found in foods. This happens especially when exposed to heat, which is why dried products in particular are affected by the artifacts (relana® 2016).

The formation of phthalimide is also observed during the roasting of coffee. In a publication published in May 2021 in the Deutsche Lebensmittelrundschau (DLR), in which we participated, it is clearly shown that significant levels of phthalimide can be detected in roasted coffees, although the associated green coffees have been proven to contain no residues.

For a correct residue assessment, it is therefore necessary to know the individual contents of phthalimide and folpet. We offer the analysis of folpet and phthalimide using modern GC-MS/MS as well as a wide range of pesticides.

Our CoA reports the sum as well as the individual values for folpet and phthalimide. If necessary, we will carry out an evaluation and help you interpret the results (especially in the case of organic products).

We will be happy to provide you with the DLR article and further literature on this topic on request.

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    Mr. Dirk Westermann
    +49 421 64905 1800