I was reading more about solubility of polystyrene and oil. I arrived on http://www.newton.dep.anl.gov/ forums. Someone was saying the unsaturated fats will not attack PS but saturated fat will do. Other webs were saying the same thing. Some stated that both will do.
Saturated fats are solid at room temperatures while unsaturated are liquid.
1) On YouTube, the liquid omega-3 supplement in gel capsule was pierced and poured to styropor cups. The oil made its way out of the cup by creating hole.
2) The diesel engine fuel softened and dissolved some parts of PS drinking cup.
3) The the fried chicken oil dissolved the styropor lunchbox after reheating in microwave oven.
I got four soft drink tanzans and filled with different oil types. From left to right – margarine, ordinary cooking oil, baby oil and pure cocoa. Cut four styrofoam pieces of uniform sizes the distributed it on four tanzans. Placed the tanzans on stainless steel plate. Heated the plate over very low flame for a few seconds just to melt the margarine. The pure cocoa also got oily but never melted.
The two styropor pieces in cooking oil and baby oil significantly decreased in size. Styropor in melted margarine showed a very little sign of shrinkage after few hours. No change cocoa’s side. Contact might not be enough to cause visible change.
A reminder… never use disposable styropor cups for serving brewed coffee, whole milk and chocolate drinks and lemon juices. They contain oils that might dissolved styropor components. Lemon contains limonene that also dissolve styropor. Skim milk, instant coffee and instant cocoa are fine – their fat content were stripped off.
Never use styrofor lunchboxes in serving oily foods such as fried chicken, paksiw, menudo, adobo and variety of sauteed vegetables.
It was mentioned on ejnet.org that build up of styropor in body can cause, neurotoxic, hematological and cytogenetic effects. (http://www.ejnet.org/plastics/polystyrene/health.html)
However, disposable styropor are everywhere and not considered as potential health risk. Migration to food is only minimal. Seeing them in stores always is a proof that they are not a major health risk.