## 5 Conclusions  
In this study, the migration of styrene was investigated in yogurt and dairy products packed in PS which were taken from the German and Italian market during 2021 using purge-and-trap (P&T) in combination with gas chromatography (GC). The used method showed low detection limits (0.5 \(\upmu\)g/kg for yogurt with 3.5% fat content and 3 \(\upmu\)g/kg for cream with 30% fat content) and can be considered suitable for trace analysis of volatiles, such as styrene, in food.  
Styrene migration levels in the refrigerated dairy products taken from the market (PS pots with net content ranging from 115 to 200 g) ranged from 5 to 30 ug/kg food when analyzed at the end of their shelf life (approx. 40 days). This is in close agreement with recently published data on styrene concentration in yogurt desserts and cream packed in PS containers which were taken from the Greek market. Significantly higher levels as reported in the literature were detected in the present study for UHT coffee creamers (10 g single portions). Styrene migration in this room temperature stored product, reached 401 ug/kg when analyzed at the end of their shelf life (approx. 6 months), which corresponds to an exposure of 4 ug styrene per single portion. Among the several parameters evaluated, the ratio between the surface contact area of the package and the quantity of the food packed (S/F), the time/temperature conditions of production/filling as well as of storage of the products were identified as the main factors influencing styrene migration into food under real application of use. The fat content might influence the styrene level but the effect, if any, was too small in relation to the variability of other parameters.  
Actual migration of styrene into refrigerated food packaged in PS was found to be much lower than that measured migrating into 50% ethanol food simulant under standardized condition. This raises the question as to whether for PS plastics compliance testing should be adapted taking into consideration the correlation between migration testing by laboratory simulations and migration in real food. Further research work is envisaged in order to gain more knowledge on styrene migration into real foods and to allow the conversion of simulated migration test results in a more realistic migration scenario also considering the corresponding real exposure of the consumer.  
Conceptualization, V.G.; Data curation, V.G., A.G., D.F. and V.H.; Formal analysis, A.G., D.F. and V.H.; Funding acquisition, V.G., A.S. and F.W.; Investigation, V.G., A.G., D.F. and V.H.; Methodology, V.G.; Project administration, V.G., A.S. and F.W.; Supervision, A.S. and F.W.; Validation, V.G. and A.S.; Visualization, V.G., A.S. and F.W.; Writing--original draft, V.G.; Writing--review & editing, V.G., A.S. and F.W. All authors have read and agreed to the published version of the manuscript.  
This research received financial support by the Styrenics Steering Committee of Plastics Europe.  
Not applicable.  
The authors gratefully acknowledge financial support by the Styrenics Steering Committee of Plastics Europe. Thanks are due to [PERSON] and [PERSON] (Fraunhofer IVV) for technical assistance as well as to [PERSON] (Systox Ltd.) for proofreading the article.  
The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.