Suitable reference materials for PAHs in baby food
JRC scientists assessed the feasibility for the production of baby food certified reference materials (CRMs) containing a number of polycyclic aromatic hydrocarbons (PAHs) at low level concentrations. The study revealed that thermal sterilisation is a suitable method of choice to ensure long-term stability (shelf life) of the product.
PAHs are a large class of chemical compounds and some of them are toxic to humans. Food can be contaminated by PAHs through environmental pollution and by industrial and domestic food production. Legislation in the EU and worldwide sets maximum limits for certain PAHs. In 2005, the European Commission listed 16 PAHs to be monitored by the EU Member States. As young children are a relatively vulnerable group of consumers, it is highly important to include baby food in the monitoring programme. To ensure the quality of data produced by the Member States' laboratories, the latter need to use appropriate methods and other quality assurance tools, such as participation in proficiency tests and the use of (certified) RMs.
For purpose of the feasibility study, a commercially available baby food, containing carrots, potatoes, tomato, white beans and meat was spiked with the 16 EU priority PAHs at a mass fraction level of 1 μg/kg. The contaminated baby food was further processed by autoclaving, freezing or freeze-drying. The homogeneity of the three materials (bottle-to-bottle variation) and their short-term (4 weeks) and long-term (18 months) stability at different temperatures were assessed. To this end, an analytical method based on a solid-liquid extraction followed by cleaning up with gel permeation chromatography (GPC) and solid phase extraction (SPE) and GC-IDMS determination, was validated in-house.
It could be demonstrated that the analytical procedure fulfilled the demands for application to the homogeneity and isochronous stability studies for the candidate baby food reference materials. All three processing methods proved suitable for the production of sufficiently homogeneous materials. Measurements on the autoclaved material provided the most promising results in terms of envisaged shelf life. Moreover, thermal sterilisation is also applied for the production of real baby food samples.