Congener patterns of polychlorinated dibenzo-p-dioxins, dibenzofurans and biphenyls as a useful aid to source identification during a contamination incident in the food chain

Polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs) and biphenyls (PCBs) are still considered among the most important groups of contaminants in the food chain. Self-control by food producers and official control by authorities are important activities that allow contaminant sources to be traced and promote further reduction in food and feed levels. Strict but feasible maximum levels were set by the EU Commission for food and feed to support this strategy, as well as action levels and thresholds. When products exceed these levels, it is important to trace the source of contamination and take measures to remove it. Congener patterns of PCDD/Fs and PCBs differ between sources and are important tools for source identification. Therefore, patterns associated with different sources and incidents relating to various feed matrices and certain agricultural chemicals were collated from published scientific papers, with additional ones available from some laboratories. The collection was evaluated for completeness by presentations at workshops and conferences. Primary sources appear to derive from 5 categories, i) by-products from production of organochlorine chemicals (e.g. PCBs, chlorophenols, chlorinated pesticides, polyvinyl chloride (PVC)), ii) the result of combustion of certain materials and accidental fires, iii) the use of inorganic chlorine, iv) recycling/production of certain minerals, and v) certain naturally occurring clays (ball clay, kaolinite). A decision tree was developed to assist in the identification of the source

Understanding possible causes of exceeding dioxin levels in palm oil by-products: An explorative study

The Rapid Alert System for Food and Feed (period 1999–2014) reported exceeding levels of dioxins (polychlorinated dibenzo-p-dioxinsand dibenzofurans (PCDD/Fs)) in palm oil by-products, such as palm fatty acid distillate (PFAD) and hydrogenated palm fatty acid distillate (HPFAD), but not in crude and refined palm oil. The aim of the present study was to gain insight into the occurrence and congener profiles of dioxin contamination during industrial processing of crude palm oil into refined oil and its by-products PFAD and HPFAD via analysis of individual congener concentrations. In total, 1217 samples from an industrial process were collected at four different points, crude palm oil at delivery (N = 202), fresh bleaching earth before bleaching (N = 84), PFAD after deodorising palm oil (N = 553), and HPFAD after hydrogenation of PFAD (N = 378). Congener profiles were analysed by GC-HRMS, and toxic equivalent (TEQ) levels were calculated using toxic equivalence factors (TEF) of WHO2005 to assess non-compliance to legal limits. All dioxin levels in crude palm oil samples were far below the action limit. All dioxin levels in fresh bleaching earth were in compliance with the maximum level. For the by-product samples, such as PFAD, 0.6% exceeded the action level, but all were below the maximum level (ML). However, for 1.3% of the HPFAD samples, the TEQ level exceeded the ML. In-depth analysis of the congener profiles revealed that after the hydrogenation step, the concentration of the lower chlorinated congeners in the HPFAD samples was higher than in the PFAD samples. The hydrogen atoms possibly replaced the chlorine atoms during hydrogenation. As these lower chlorinated congeners have a higher TEF, when they are regulated, their contribution to the calculated TEQ is higher, which resulted in some HPFAD samples exceeding the legal limit. Further research is needed to obtain insight into the changes in PCDD/F congener profiles during the hydrogenation of palm oil products.</p

Understanding possible causes of exceeding dioxin levels in palm oil by-products: An explorative study

The Rapid Alert System for Food and Feed (period 1999–2014) reported exceeding levels of dioxins (polychlorinated dibenzo-p-dioxinsand dibenzofurans (PCDD/Fs)) in palm oil by-products, such as palm fatty acid distillate (PFAD) and hydrogenated palm fatty acid distillate (HPFAD), but not in crude and refined palm oil. The aim of the present study was to gain insight into the occurrence and congener profiles of dioxin contamination during industrial processing of crude palm oil into refined oil and its by-products PFAD and HPFAD via analysis of individual congener concentrations. In total, 1217 samples from an industrial process were collected at four different points, crude palm oil at delivery (N = 202), fresh bleaching earth before bleaching (N = 84), PFAD after deodorising palm oil (N = 553), and HPFAD after hydrogenation of PFAD (N = 378). Congener profiles were analysed by GC-HRMS, and toxic equivalent (TEQ) levels were calculated using toxic equivalence factors (TEF) of WHO2005 to assess non-compliance to legal limits. All dioxin levels in crude palm oil samples were far below the action limit. All dioxin levels in fresh bleaching earth were in compliance with the maximum level. For the by-product samples, such as PFAD, 0.6% exceeded the action level, but all were below the maximum level (ML). However, for 1.3% of the HPFAD samples, the TEQ level exceeded the ML. In-depth analysis of the congener profiles revealed that after the hydrogenation step, the concentration of the lower chlorinated congeners in the HPFAD samples was higher than in the PFAD samples. The hydrogen atoms possibly replaced the chlorine atoms during hydrogenation. As these lower chlorinated congeners have a higher TEF, when they are regulated, their contribution to the calculated TEQ is higher, which resulted in some HPFAD samples exceeding the legal limit. Further research is needed to obtain insight into the changes in PCDD/F congener profiles during the hydrogenation of palm oil products.</p