Development of matrix reference materials for silver nanoparticles in meat
Scientists from the JRC in close collaboration with various European Institutions, successfully completed a feasibility study for a reference material of silver nanoparticles in chicken meat. Despite the fact that some challenges regarding method development, stability and characterisation have been identified, the materials developed in this study can serve as a first step towards improving analytical methods and developing certified reference materials.
EU Regulation 1169/2011 requires food producers to inform consumers whether ingredients are present in their nano-form. A control of the correct implementation of this legislation is only possible with reliable and validated methods, which in turn require reference materials.
Materials impregnated with silver nanoparticles exist already on the market. Those which may come into contact with food include refrigerators , cutting boards and food storage containers. It has been demonstrated that silver nanoparticles can migrate from these materials into the food they come into contact with. As a result, silver nanoparticles in a meat matrix were chosen as one model system of the FP7 Project NanoLyse (Grant agreement 245162), which aims to ascertain principle that the development of methods for the detection and quantification of nanoparticles in food is possible.
Within this project, scientists of the JRC-Institute for Reference Materials and Measurements (IRMM) produced the first reference materials for the detection and quantification of silver nanoparticles in a food matrix. The work is challenging, as silver nanoparticles are prone to dissolution as well as to agglomeration. Therefore, the complete extraction and quantification of the particles without destroying them is a challenging exercise. For the production of the materials, a suspension of nanoparticles in water was mixed with chicken meat puree and was shock-frozen in liquid nitrogen at -150 °C. This resulted in a homogeneous material with only moderate agglomeration of the silver nanoparticles. As no detectable changes were observed over a period of 6 months, it was concluded that the material is qualified to serve as a reference material. However, the detection of quantification of the nano silver particles in the material still poses a challenge due to the lack of suitable analytical methods. Improved analytical methods are necessary for the assessment of the material's homogeneity and for the assignment of property values