Dioxin food crises and new POPs: challenges in analysis.

When more than a million broiler chickens suddenly and unexpectedly died in the eastern and midwestern parts of the United States in late 1957; the first dioxin crisis record was set [1]. It took nearly 10 years of investigation to pinpoint 1,2,3,7,8,9hexachlorodibenzo-p-dioxin as the hydropericardiumproducing factor, the responsive agent for the so-called chick edema disease [2]. This toxic material was present in by-product fatty acids incorporated in feed. Contaminated oleic and stearic acids originated from producers who used inedible tallow collected after hide-stripping operations during which dioxincontaminated pentachlorophenol was widely used as a hide preservative. This pentachlorophenol-related fatty acid contamination motivated the development of the first analytical method to measure selected polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) in animal fat samples [3]. The Yusho and Yu-Cheng catastrophes both confirmed the importance of controlling food processing to avoid dangerous episodes of human exposure via food consumption [4, 5]. The 1999 Belgian dioxin chicken-gate affair ultimately demonstrated the economic damage that could result from such a contamination episode, and pushed the European Union (EU) to start an efficient and pro-active monitoring program to ensure the proper quality of European food and feed and to try to maintain most of the population below tolerable weekly intake [6, 7]. Therefore, starting back in early 2000, the European Commission (EC) began to propose legislation and began implementation of decisions to regulate dioxin and dioxinlike (DL-)PCB levels in foodstuffs and animal feed [8]. The EC strategy relies on the coordination of actions at the EU level to implement continuous monitoring and produce comprehensive and reliable data. First, maximum residue levels (MRLs) were established for seventeen 2,3,7,8-substituted dioxins and furans only, and set as levels as low as reasonably achievable (ALARA), on the basis of the limited data available at that time [9]. The twelve DL-PCBs were later added for both food and feed to enable better toxicological evaluation [10–13]. Further establishment of action levels, levels which if exceeded by levels of PCDD/Fs and/ or DL-PCBs should initiate investigations to identify the source of contamination, later completed the strategy [14]. To efficiently protect consumers’ health, a rapid alert system for food and feed (RASFF) was also introduced to ensure immediate notification to the EC if a member state had any information about a serious health risk related to PCDD/F contamination derived from food or feed [15]. Originally, in early 2000, it was challenging to timely and cost-effectively perform food–feed control. All together, depending on the position and number of chlorine atoms present in the molecule, PCDD/Fs and PCBs represent more