1. PCDD/F and PCP in Guar Gum

Contamination of Guar Gum from India with PCDD/F and PCP

The Rapid Alert System for Food and Feed (RASFF) of the European Commission received on 24 July 2007 in the evening a notification from the competent authorities of Switzerland concerning a finding of a serious contamination by dioxins and pentachlorophenol in guar gum originating from India.
An overview of this incident and a summary of the action taken by EU Commission on this contamination of guar gum is available. Additinally the guar gum case and resulting analytical problems were presented at the Dioxin Conference 2008:

• Contamination of Guar Gum from India with Pentachlorophenol (PCP) and Dioxins
  (CRL for Dioxins and PCBs in Food and Feed, August 23, 2007)
• The guar gum case: Contamination with PCP and dioxins and analytical problems (Organohalogen Compd 70, 2008)

Proficiency test on the determination of PCDD/F, PCB and PCP in Guar Gum

In the interest of an uniform approach within the EU, the Commission services derived reference points of action for unacceptable levels of dioxins and pentachlorophenol in guar gum. Some analytical results for determination of these contaminants in guar gum raised questions regarding reliability of the applied methods.
Therefore it was concluded at the workshop of the CRL for dioxins and PCBs in Food and Feed (held on 5-6 November 2007 with representatives from the Commission, National Reference Laboratories [NRLs], the CRL for Single Residue Methods [CRL-SRM] Stuttgart, Germany, and invited experts) to organize a study on determination of dioxins (PCDD/F), PCBs (dioxin-like PCBs and indicator PCBs) and pentachlorophenol (PCP) in guar gum samples in 2008.
This proficiency test was open for participation of European national reference and official laboratories and private laboratories worldwide performing analyses of PCDD/F, PCB and PCP.53 official and private laboratories analyzing PCDD/F and PCB using confirmatory and screening methods and 41 laboratories analyzing PCP participated in this Guar Gum PT. Preliminary results for PCDD/F, PCB and PCP were discussed at the CRL-NRL workshop in July 2008. A summary of the results for PCDD/F of this proficiency test and further follow-up anallyses were presented at the Dioxin conference in Beijing 2009

• Proficiency test on the determination of PCDD/Fs and PCP in guar gum and follow-up analyses (Organohalogen Compd 71, 2009)

1. Determination of PCDD/F and PCB in Feedingstuff

Extraction procedures for the determination of PCDD/F and dioxin-like PCBs in products of mineral origin, premixtures or compound feed containing products of mineral origin or trace elements vary widely. One important task of the CRL-NRL network in 2006 and 2007 was the harmonization of extraction procedures for these products.

Therefore the CRL for Dioxins and PCBs in Feed and Food organized two interlaboratory studies on extraction technqiues for PCDD/Fs and PCBs in different mineral feed matrices in 2006 and 2007. Three different matrices were tested in these studies:

- Sepiolite,
- Fullers earth and
- Manganese oxide.

The results and conclusions of these studies were discussed at the CRL-NRL workshops in 2006 and 2007 and recommendations were published:

• Extraction procedures for PCDD/F in mineral feed - Sepiolite (October 2006)
• Recomendation for extraction procedures - Feedingstuff (December 2007)

In addition the results of these comprehensive studies on extraction techniques of mineral feed additives were also presented at the Dioxin Conference (International Symposium on Halogenated Persistent Organic Pollutants (POPs)) in 2007 and 2008:

• Harmonization of Extraction Methods for the Determination of PCDD/F in Mineral Feed
  (Organohalogen Compd 69, 2007)
  
• Interlaboratory study on harmonization of extraction procedures for determination of PCDD/F and PCB in feedingstuff (Organohalogen Compd 70, 2008)

1. Methods of sampling and anlysis

2. Maximum and action levels