Modern technological strategies of food manufacturing may inevitably produce an unknown quantity of nanoscale ingredients or impurities in many processed or packaged foods. The indirect formation of these nanoscale contaminants, which are predicted to be emulsifier-like complex lipidaceous materials that form during heat-induced food processing, has not been studied. Moreover, the effects of chronic exposure to nanoscale contaminants on human health and the environment are also unknown. In this present study, we identify and extract emulsifier-like ultrafine carbon nanostructures (UFCNs) from bread using a facile method. The physico-chemical properties of the isolated particles were analyzed using UV-vis-NIR spectroscopy, X-ray diffraction (XRD) and transmission electron microscopy (TEM). The isolated nanoparticles exhibited fluorescence and a crystalline nature. TEM images revealed that carbon particles are 2-10 nm in diameter. An in vitro toxicological assessment was carried out in human mesenchymal stem cells (hMSCs) as a cellular model. Acute dose-response relationships were analyzed using an MTT assay, cell morphological assessments, and assessments of intra-cellular stress, i.e., ROS and mitochondrial trans-membrane potential and analysis cell cycle progression. The expression of oxidative stress-related genes was analyzed using real-time qPCR. Cell viability and morphology analysis results indicated that UFCNs slightly reduced cell viability and induced cellular morphological changes. UFCNs induced acute mitochondrial membrane damage at 400 mu g/mL and generated ROS in hMSCs in a dose dependent manner. The expression of GPX1, Bcl2, CAT and SOD genes showed dose- and time-dependent relationships in UFCN-treated cells. Our findings suggest that UFCNs induced cytotoxicity at 400 mu g/mL in hMSCs. (C) 2016 Elsevier Ltd. All rights reserved.