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Safety assessment of the substance Poly((R)-3-hydroxybutyrate-co-(R)-3-hydroxyhexanoate) for use in food contact materials

on the Wiley Online Library


Panel members at the time of adoption

Claudia Bolognesi, Laurence Castle, Jean-Pierre Cravedi, Karl-Heinz Engel, Paul Fowler, Roland Franz, Konrad Grob, Rainer Gürtler, Trine Husøy, Sirpa Kärenlampi, Wim Mennes, Maria Rosaria Milana, André Penninks, Vittorio Silano, Andrew Smith, Maria de Fátima Tavares Poças, Christina Tlustos, Detlef Wölfle, Holger Zorn and Corina-Aurelia Zugravu


This opinion of the EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF Panel) deals with the safety assessment of Poly((R)-3-hydroxybutyrate-co-(R)-3-hydroxyhexanoate), Chemical Abstracts Service (CAS) No 147398-31-0 and food contact material (FCM) substance No 1059, to produce packaging for contact with fresh whole fruits and vegetables. This biodegradable (co)polymer is produced by fermentation of genetically modified microorganisms (Cupriavidus necator) using palm oil. Specific migration was not tested because it is currently not foreseen by Regulation (EU) No 10/2011 for FCM for these two food groups. Overall migration was lower than 1 mg/dm2. No genotoxicity data are required for Poly((R)-3-hydroxybutyrate-co-(R)-3-hydroxyhexanoate) because of its high molecular weight. Its low molecular weight fraction below 1,000 Da is 0.5% and its migration is expected to be negligible. The polymer's major unit (89–99%), 3-hydroxybutyric acid, is an intermediate in fatty acid metabolism. Its minor unit (1–11%), 3-hydroxyhexanoic acid, was tested negative for bacterial gene mutations. Degradation products, which may be present in the (co)polymer, are crotonic acid and (E)-2-hexenoic acid. Crotonic acid is authorised for use in FCM with a specific migration limit (SML) of 0.05 mg/kg food; for (E)-2-hexenoic acid no indication for genotoxicity was identified by the EFSA CEF Panel in its 2010 group evaluation of flavouring substances in FGE.05Rev2. The CEF Panel concluded that the substance Poly((R)-3-hydroxybutyrate-co-(R)-3-hydroxyhexanoate) is not of safety concern if used alone or in blends with other polymers for contact with unpeeled/uncut fruits and vegetables, according to food groups Ref. nos 04.01 and 04.04 as specified in Regulation (EU) No 10/2011. Migration of crotonic acid should not exceed 0.05 mg/kg food and if this SML is met, then migration of (E)-2-hexenoic acid will also not exceed 0.05 mg/kg food.