Potential Migration and Health Risks of Heavy Metals and Metalloids in Take-Out Food Containers in South Korea.

The consumption of take-out food has increased worldwide; consequently, people are increasingly being exposed to chemicals from food containers. However, research on the migration of metals from containers to food is limited, and therefore, information required to determine the health risks is lacking. Herein, the amount of transfer of nine metals and metalloids (Pb, Sb, Cd, Ge, Co, Mn, Sn, As, and Hg) from food containers to food in South Korea was assessed from take-out food containers classified into paper and plastic container groups. The sample containers were eluted over time by either warming with 4% acetic acid at 70 °C or cooling with 4% acetic acid at 100 °C /deionized water at 25 °C. It was analyzed using an inductively coupled plasma mass spectrometer and a direct mercury analyzer. The reliability of the quantitative results was verified by calculating the linearity, limit of detection, and limit of quantification. We found that the amount of metals and metalloids (Pb, Sb, Cd, and Co) eluting over time was highly significant in the plastic group. Regardless of the food simulant and elution time, the amount of Sb transferred from the food containers to food was substantially higher in the plastic (average concentration: 0.488-1.194 µg/L) than in the paper group (average concentration: 0.001-0.03 µg/L). Fortunately, all food containers were distributed at levels safe for human health (hazard index: 0.000-64.756%). However, caution is needed when warm food is added to food containers. Overall, our results provide baseline data for the management and use of take-out containers.

Role of TGF-ß in Survival of Phagocytizing Microglia: Autocrine Suppression of TNF-α Production and Oxidative Stress.

Microglia are recognized as residential macrophageal cells in the brain. Activated microglia play a critical role in removal of dead or damaged cells through phagocytosis activity. During phagocytosis, however, microglia should survive under the harmful condition of self-producing ROS and pro-inflammatory mediators. TGF-ß has been known as a classic anti-inflammatory cytokine and controls both initiation and resolution of inflammation by counter-acting inflammatory cytokines. In the present study, to understand the self-protective mechanism, we studied time-dependent change of TNF-α and TGF-ß production in microglia phagocytizing opsonized-beads (i.e., polystyrene microspheres). We found that microglia phagocytized opsonized-bead in a time-dependent manner and simultaneously produced both TNF-α and TGF-ß. However, while TNF-α production gradually decreased after 6 h, TGF-ß production remained at increased level. Microglial cells pre-treated with lipopolysaccharides (a strong immunostimulant, LPS) synergistically increased the production of TNF-α and TGF-ß both. However, LPS-pretreated microglia produced TNF-α in a more sustained manner and became more vulnerable, probably due to the marked and sustained production of TNF-α and reduced TGF-ß. Intracellular oxidative stress appears to change in parallel with the microglial production of TNF-α. These results indicate TGF-ß contributes for the survival of phagocytizing microglia through autocrine suppression of TNF-α production and oxidative stress.