Therefore, in the present study, we also used acetone as the extraction solvent. However, this procedure might be given to leading an overestimation of the risk because it was expected that acetone had greater extraction capacity compared to the authentic simulant which represents the migration of styrene oligomers from polystyrene into food in general use. In this context, regardless of what the genotoxicity tests result in positive or negative, we can obtain the highest doses, at which the genotoxic responses become equivalent to the spontaneous levels. Then, to avoid overemphasis

of the risk, we can compare these doses and the concentration of the styrene oligomers extracted by simulant and this comparison considering a margin of extraction amount would give us valuable insight to assess the risk of the styrene oligomers extracted from polystyrene. Compared with 50% ethanol, acetone clearly had a greater capacity to extract SDs and STs. The concentrations BMS 354825 of SDs and STs in the test solution were 540 ppm and 13,431 ppm, respectively (total, 13,971 ppm), whereas the maximum total concentration of SDs and STs that can be extracted from polystyrene with 50% ethanol solution is 70 ppb [17]. Therefore, the total concentration of SDs and STs extracted with acetone in the test solution was approximately 200,000 times higher than that extracted Selleck Olaparib with 50% ethanol solution. This result shows that the

capacities of stiripentol solvents to extract styrene oligomers from polystyrene are influenced by the polarity of each solvent. Water, which possesses the highest polarity among solvents listed in Table 5, showed the lowest capacity to extract styrene oligomers. On the other hand, regarding the pattern of compounds extracted from the polystyrene, the ratio of SDs to STs became greater when the polarity of the solvent became higher [19]. In addition, the ratio of SDs to

STs in the test solution used in the present study was not so different from that in the GPPS pellets themselves, showing that acetone extraction allowed cells to be exposed to test samples containing a sufficiently high concentration of SDs and STs in a similar ratio to that found in the original GPPS pellets. Both the Ames test and the in vitro chromosomal aberration test, which are the tests required by the FDA and EFSA for the safety evaluation of food packaging, were negative even when high concentrations of oligomers were used compared to the case of fatty-food simulant, suggesting that the risk of genotoxicity of styrene oligomers migrated from polystyrene food packaging into food is very low. Our results also provide useful data on the clastogenic and polyploidy-inducing potential of styrene oligomers. Because of the low solubility of styrene oligomers in aqueous condition, it was expected that the mixture of styrene oligomers would precipitate out of the culture medium during the in vitro chromosomal aberration test, which indeed occurred at doses of 1250 μg/mL or greater.