Legal regulation for phosphonic acid residues in food
Consideration of various entry ways for new maximum residue levels of phosphonic acid
Nov 2024 (Update). On 29 October 2024, Regulation (EU) 2024/2619 amending the maximum residue levels of fosetyl, potassium phosphonates and disodium phosphonates entered into force. The regulation also describes the change in the previous maximum residue definition from “fosetyl-Al (sum of fosetyl, phosphonic acid and its salts, expressed as fosetyl)” to “phosphonic acid and its salts, expressed as phosphonic acid”. The regulation applies from 29 April 2025.
This overview presents an outline of the changes and what they mean for the findings of fosetyl.
Entry ways of phosphonic acid into food
Phosphonic acid is, among other things, a degradation product of the fungicide fosetyl aluminum (fosetyl-Al), which is used, for example, in the cultivation of fruit and vegetables. However, residues of phosphonic acid in food cannot always be traced back to the use of fosetyl-Al, as there may also be other routes of entry. Possible entry routes include disodium phosphonate and potassium phosphonate, which are authorised substances in the EU.
Potassium phosphonates are also used as a component of other agriculturally relevant products (e.g. fertilisers, plant strengthening agents, soil improvers), so that the treatment of plants with such products can lead to the detection of phosphonic acid residues in the corresponding agricultural products. The EU therefore considers it necessary to take into account the possible entry route of these agents when setting the corresponding maximum residue levels.
Furthermore studies also show that phosphonic acid also occurs naturally in the environment.
Changes at a glance
Overall, the regulation (EU) 2024/2619 of the EU Standing Committee on Plants, Animals, Food and Feed provides for reductions in MRLs for some products and increases for others. The maximum levels range from the respective specific limit of determination, e.g. 1.5 mg/kg for cranberries and dates or 20 mg/kg for tea and coffee, to specific maximum levels of 1000 mg/kg for almonds and 1500 mg/kg for rooibos.
The previous 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. With the draft amendment and the new residue definition "phosphonic acid and its salts, expressed as phosphonic acid", these are now to be included. In addition, fosetyl will no longer be part of the definition in future.
Significance for fosetyl findings
Fosetyl-Al initially decomposes to fosetyl during degradation, which was previously part of the residue definition and was therefore regulated together with phosphonic acid in the maximum total content. Regarding the standard maximum level of 0.01 mg/kg according to Regulation (EC) No. 396/2005, the footnote states:
"The results of fosetyl should not be taken into account and the default maximum level of 0.01 mg/kg in accordance with Article 18(1)(b) of Regulation (EC) No 396/2005 does not apply. The MRL for its metabolite phosphonic acid shall apply."
This means that findings of fosetyl are not taken into account in an assessment. Only the maximum level for phosphonic acid and its salts applies.
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Written by:
Sandra Kobüssen
Eurofins Dr. Specht International GmbH