Risks for human and animal health related to the presence of phorbol esters in Jatropha kernel meal
Following a request from the European Commission, the risks for human and animal health related to the presence of phorbol esters (PEs) in Jatropha kernel meal were assessed by the EFSA Panel of Contaminants in the Food Chain (CONTAM). Jatropha curcas (Jatropha) seeds contain substantial amounts of extractable oil utilised for biodiesel production. The remaining protein-rich products (seed meal or kernel meal) may be used as a protein source in animal feed after removal of anti-nutritive factors and toxic PEs. The available data on absorption of Jatropha PEs after oral ingestion, biotransformation, elimination, and dose-dependent toxic effects are very limited, and only for pigs a no observed adverse effect level (NOAEL) of 0.4 mg PEs/kg bw per day (12-O-tetradecanoylphorbol-13-acetate (TPA) equivalent), based on decreases in body weight gain and feed intake, could be identified from short-term feeding studies. No health based guidance value for humans could be established. Processes that almost completely remove or degrade toxic PEs in Jatropha products are available, resulting in levels below the limit of detection of 3 mg Jatropha PEs/kg (TPA equivalent). Replacement of 50% of the protein in compound feeds with treated Jatropha materials would result in animal exposures that are still 10 to 200-fold lower than the NOAEL for pigs. The CONTAM Panel concluded that such use of Jatropha material would not pose a health risk to pigs and that the risk to other species is likely to be low. The transfer of Jatropha PEs to animal derived products is unknown. In a human exposure scenario using a 50% transfer rate from feed to milk, a daily intake of 1 µg Jatropa PEs/kg bw per day was calculated. The CONTAM Panel concluded that more data are needed to draw firm conclusions on human risks.