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Phosphonic acid- Amendment of the residue definition and new maximum residue levels planned

Phosphonic acid- Amendment of the residue definition and new maximum residue levels planned

In the currently valid version of Regulation (EC) No. 396/2005, phosphonic acid is regulated together with fosetyl as a maximum residue limit. This means that residues of phosphonic acid and fosetyl in foodstuffs are assessed as degradation products of the fungicide fosetyl aluminium (fostyl-Al). The regulation lists corresponding maximum residue levels for the following groups, for example:

Cocoa: 2 mg/kg

Coffee beans: 5 mg/kg

Teas (except herbal teas): 5 mg/kg

However, findings of phosphonic acid in food do not necessarily indicate the use of fosetyl-Al. Another possible source is phosphonates such as disodium phosphonate and potassium phosphonate. Which are used, for example, as fertilisers, plant strengthening agents and soil conditioners.

The use of such products can therefore lead to the detection of phosphonic acid residues in the corresponding agricultural products. Phosphonate in food therefore does not necessarily have to be a pesticide residue.

According to the BNN, in the case of organic products, phosphonic acid concentrations of 0.05 mg/kg or more should already be checked to determine whether agricultural use has taken place that is not compatible with the EU Organic Farming Regulation.

The current residue definition ‘Fosetyl-Al (sum of fosetyl, phosphonic acid and its salts, expressed as fosetyl)’ does not take into account the entry routes of phosphonic acid into food. The Standing Committee on Pesticide Residues in the EU is therefore introducing a new residue definition ‘phosphonic acid and its salts expressed as phosphonic acid’ in its draft regulation, which includes the entry routes of phosphonic acid. Fosetyl will no longer be part of the definition in future. In addition, the maximum residue levels (MRLs) for the individual groups will change. For coffee beans and tea, for example, a maximum level of 20 mg/kg is envisaged. A date for the publication of the amending regulation has not yet been set.

Analysis of polar substances

Fosetyl and phosphonic acid are among the polar substances that cannot be analysed using the multi-residue method (Quechers) due to their special chemical properties. CR3-Analyitk has established an efficient method for the sensitive detection of these polar substances by LC-MS/MS with very low limits of quantification. These include

-fosetyl/ phosphonic acid

-chlorate/ perchlorate

-chlormequat/ mepiquat

If you have any questions about the analysis and the analysis spectrum, please do not hesitate to contact us.  If required, we can also carry out an evaluation of the analysis results in accordance with (EC) No. 396/2005 or BNN association requirements for organic products.

Sources

Regulation (EC) No. 396/2005 on maximum residue levels of pesticides in or on food and feed (in the currently valid version)

BNN factsheet phosphonic acid, potassium phosphonate (potassium salt of phosphonic acid),

Fosetyl aluminium, summary of the state of knowledge, September 2020