Solubility-driven toxicity of CuO nanoparticles to Caco2 cells and Escherichia coli: Effect of sonication energy and test environment.

Due to small size and high surface energy nanoparticles (NPs) tend to agglomerate and precipitate. To avoid/diminish that, sonication of NPs stock suspensions prior toxicity testing is often applied. Currently, there is no standardized particle sonication protocol available leading to inconsistent toxicity data, especially if toxicity is driven by NPs' dissolution that may be enhanced by sonication. In this study we addressed the effect of sonication on hydrodynamic size (Dh), dissolution and toxicity of copper oxide (CuO) NPs to mammalian cell line Caco-2 in vitro and bacteria Escherichia coli in the respective test environments (cell culture MEM medium, bacterial LB medium and deionised (DI) water). NPs were suspended using no sonication, water bath and probe sonication with different energy intensities. Increased sonication energy (i) decreased the Dh of CuO NPs in all three test environments; (ii) increased dissolution of NPs in MEM medium and their toxicity to Caco-2; (iii) increased dissolution of NPs in LB medium and their bioavailability to E. coli; and (iv) had no effect on dissolution and antibacterial effects of NPs in DI water. Thus, to reduce variations in dissolution and toxicity, we recommend sonication of NPs in DI water following the dilution into suitable test media.

Good manufacturing practice in brazilian wheat mills with particular reference to the flour fortification

Iron deficiency anemia (IDA) is a widespread nutritional disorder that affects a significant proportion of the Brazilian population. The obligatory fortification of wheat flour with iron and folic acid represents a strategy of the Brazilian Ministry of Health for combating IDA. However, several studies have reported the occurrence of iron in excessive concentrations and insufficient contents of folic acid in commercial flour samples. In the light of these information, a participatory observational study on the wheat flour production processes was undertaken in 11 major flour mills located in the São Paulo state, Brazil. This study aimed at writing a detailed good manufacturing practice (GMP) guidelines for the industrial sectors, including directives for standardized operational procedures (SOPs) on the flour fortification. The outcomes of this study are a GMP checklist and the recommended SOPs, which help to standardize the production processes in flour fortification, which currently is incongruous one, and also to facilitate the work of the government health inspectors...