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Nitrofurans as an example - How to control zero tolerance?

Nitrofurans as an example - How to control zero tolerance?. Katrin Hoenicke and Robert Gatermann Eurofins Analytik GmbH Wiertz-Eggert-Jörissen Hamburg, Germany. The Situation. Council Regulation (EC) No. 2377/90 , Annex IV :

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Nitrofurans as an example - How to control zero tolerance?

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  1. Nitrofurans as an example - How to control zero tolerance? Katrin Hoenicke and Robert Gatermann Eurofins Analytik GmbH Wiertz-Eggert-Jörissen Hamburg, Germany 3rd AOAC Europe - Eurachem Symposium Brussels, Belgium

  2. The Situation • Council Regulation (EC) No. 2377/90, Annex IV: • Pharmacologically active substances for which no MaximumResidue Limits (MRLs) are fixed • No ADIdue to their nature of toxicity or a lack of data • No safe limit, unacceptable at any concentration • Accepted to be banned • Controled with zero-tolerance 3rd AOAC Europe - Eurachem Symposium Brussels, Belgium

  3. Zero-Tolerance What does zero-tolerance mean? • The respective residue should not be detectable • ‚Not detectable‘ is based on the limit of detection (LOD) • Nowadays: LOD has decrased drastically • Significance of regulations must sometimes be questioned with regards to the toxicity of residues determined in the lower ppb-level 3rd AOAC Europe - Eurachem Symposium Brussels, Belgium

  4. Zero-tolerance • Basic Hypothesis of the zero-tolerance concept: ‚Residues of pharmacologically active substances in food of animal origin are a result of the use of medicines in food producing animals‘ • Anti-Thesis: A concentration level close to‚zero‘ could be caused byother sources than the useof medicines infood producing animals 3rd AOAC Europe - Eurachem Symposium Brussels, Belgium

  5. Possible other sources • Cross contamination from former use • Cross contamination from use in human medicine • Environmental contamination • Natural occurrence / formation • To discuss: The limitation of azero-toleranceconcept which is dependent on the sophistication of analytical equipment 3rd AOAC Europe - Eurachem Symposium Brussels, Belgium

  6. Nitrofurans as an example Nitrofurans: • Banned within the EU in the 90ies (zero-tolerance) • In those days: Control was limited by the analytical technique • Nowadays: • Technical developments in LC/MS-MS lowered LODs for nitrofuranmetabolitesmore than 4 orders of magnitude • Minimum Required Performance Limit (MRPL) for nitrofuran metabolites was set to 1 µg/kg (Commission Decision 2002/657/EC) 3rd AOAC Europe - Eurachem Symposium Brussels, Belgium

  7. SEM nitrofurazone Semicarbazide – more than a nitrofuran metabolite Semicarbazide (SEM): • Characteristic marker of the nitrofuran nitrofurazone • Zero-tolerances for SEM in food are in force • Toxicological studies of SEM: Weak mutagenic activity, mainly in the absence of a metabolic activating system (EFSA, 2003) 3rd AOAC Europe - Eurachem Symposium Brussels, Belgium

  8. Semicarbazide – more than a nitrofuran metabolite Other possible sources for SEM in food products: • Azodicarbonamide (ADC) • Identification of SEM in food packaged in glass jars where ADC is used as a blowing agent in the gaskets of the lids (EFSA, 2003) • Identification of SEM in flour to which ADC was added as an improver (Pereira et al., 2004) • Hypochlorite Treatment • Identification of SEM in carrageenan (E 470a) due to a bleaching step using hypochlorite (Hoenicke et al., 2004) 3rd AOAC Europe - Eurachem Symposium Brussels, Belgium

  9. Semicarbazide – more than a nitrofuran metabolite Other possible sources for SEM in food products: • Heat treatment • Identification of SEM in egg white powder due to a pasteurisation step (Gatermann et al., 2004) • Natural occurrence • Identification of SEM in dried marine products (crayfish, algae) (Saari and Peltonen, 2004, Hoenicke et al., 2004) • Numerous food products have been destroyed erroneously!!! 3rd AOAC Europe - Eurachem Symposium Brussels, Belgium

  10. Consequences for SEM testing • November 2003, Community Reference Laboratory (CRL), Fougères: ‚Illegal use of nitrofurazone can be detected by targeting the bound residues of SEM‘ • But: SEM from other sources was also shown to be rapidely bound • December 2004, Standing Comittee on the Food Chain and Animal Health (SCFCAH): ‚SEM in the animal fraction of composite food may result from the use of nitrofurazone in live animals, but may also result from other sources or chemical reactions during processing‘ • Appropriate statement should accompany the analytical test report 3rd AOAC Europe - Eurachem Symposium Brussels, Belgium

  11. Commission Decision 2005/34/EC – Progress in regulation • Harmonised standards for handling with zero-tolerances • ‚The MRPL correspond to the average limit above which the detection of a substance or its residue can be construed as methodologically meaningful‘ • Introduction of ‚action limits‘ • MRPL shall be used as reference point for action • Only test results at or above the MRPL shall be considered non- compliant with Community legislation • Residues below the MRPLshould be construed as not of immediate concern • Useful tool to handle with zero tolerances 3rd AOAC Europe - Eurachem Symposium Brussels, Belgium

  12. Commission Decision 2005/34/EC – Ongoing problems • ‚MRPLs shall be used as reference points for action irrespective of the matrix tested‘ • In the case of composite or processed food other possible sources should be considered 3rd AOAC Europe - Eurachem Symposium Brussels, Belgium

  13. Conclusion • Introduction of MRPLs as ‚action limits‘is the only acceptable compromise to deal with zero-tolerances • Use of MRPLs as ‚action limits‘ for all matrices without any prove is not possible especially in the case of composite or processed food products 3rd AOAC Europe - Eurachem Symposium Brussels, Belgium

  14. References • European Food Safety Authority (EFSA) (2003) Statement of the Scientific Panel on Additives, Flavourings, Processing Aids and Materials in Contact with Food updating the advice on available semicarbazide in packaged foods. EFSA/AFC/FCM/17-final, 1 October 2003. • Pereira, A.S., Donato, J.L., De Nucci, G. (2004) Implications of the use of semicarbazide as a metabolic target of nitrofurazone contamination in coated products, Food Addit. Contam. 21, 63-69. • Hoenicke, K., Gatermann, R., Hartig, L., Mandix, M., Otte, S. (2004) Formation of semicarbazide (SEM) in food by hypochlorite treatment: is SEM a specific marker for nitrofurazone abuse? Food Addit. Contam. 21, 526-537. • Gatermann, R., Hoenicke, K., Mandix, M. (2004) Formation of semicarbazide (SEM) from natural compounds in food by heat treatment, Czech J. Food Sci. 22, 353-354. • Saari, L., Peltonen, K. (2004) Novel source of semicarbazide: levels of semicarbazide in cooked crayfish samples determined by LC/MS/MS, Food Addit. Contam. 21, 825-32. 3rd AOAC Europe - Eurachem Symposium Brussels, Belgium

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