title: Kaolinic clay derived PCDD/Fs in the feed chain from a sorting process for potatoes.
abstract: At the end of 2004, during a routine monitoring project, high levels of PCDDs in milk from two farms were found. Using a bioassay and the congener patterns obtained by HRGC/HRMS, the source was traced back to the use of kaolinic clay for sorting potatoes in a production process of French fries. Rest products, especially peelings after scrubbing, were used as feed for dairy cows. Levels of PCCD/Fs in this product amounted to 44 ng WHO(1998)-TEQ kg(-1) (88% dw). The maximum level observed in milk was 20 pg WHO(1998)-TEQ g(-1) fat. A Physiologically Based PharmacoKinetic (PB-PK) model was used to model three data obtained before eliminating the source in order to estimate the starting time of the contamination of the cows, the steady-state level after prolonged contamination and the kinetics of the decrease in the levels after removal of the source. Samples of milk were continuously collected for several months showing a decrease to levels below the product limit of 3 pg WHO(1998)-TEQ g(-1) fat within 2 months, in excellent agreement with the decrease predicted by the PB-PK model. Different batches of clay were sampled and analysed, showing varying levels of especially PCDDs. All clays were confirmed to be kaolinic clay using X-ray analysis. Other by-products used for animal feed were also contaminated and led to precautionary measures at a few hundred farms, especially pig farms. However, levels in other animal derived products like pig meat did not exceed the product limits.
authors.affiliation: RIKILT Institute of Food Safety, Bornsesteeg 45, 6708 PD Wageningen, The Netherlands. ron.hoogenboom@wur.nl
authors.forename: Ron
authors.initials: R
authors.lastname: Hoogenboom
authors.forename: Marco
authors.initials: M
authors.lastname: Zeilmaker
authors.forename: Jan van
authors.initials: Jv
authors.lastname: Eijkeren
authors.forename: Kees
authors.initials: K
authors.lastname: Kan
authors.forename: Marcel
authors.initials: M
authors.lastname: Mengelers
authors.forename: Dion
authors.initials: D
authors.lastname: Luykx
authors.forename: Wim
authors.initials: W
authors.lastname: Traag
mesh_terms: D000538:Aluminum Silicates / Q000737:chemistry*; D000821:Animal Feed; D000818:Animals; D001572:Benzofurans / Q000032:analysis* / Q000737:chemistry / Q000493:pharmacokinetics; D002417:Cattle; D000077215:Clay; D007616:Kaolin / Q000737:chemistry*; D008892:Milk / Q000737:chemistry; D000072317:Polychlorinated Dibenzodioxins / Q000031:analogs & derivatives* / Q000032:analysis / Q000737:chemistry / Q000493:pharmacokinetics; D011108:Polymers / Q000032:analysis* / Q000737:chemistry / Q000493:pharmacokinetics; D011198:Solanum tuberosum / Q000737:chemistry*
chemical_list: D000538:Aluminum Silicates; D001572:Benzofurans; D000072317:Polychlorinated Dibenzodioxins; D011108:Polymers; C016068:polychlorodibenzofuran; D007616:Kaolin; D000077215:Clay