## 2 Results and Discussion
### VOCs Isolated from Cheeses Wrapped in Cling-Films for Retail Use  
The migration of VOCs depends on the characteristics of the polymer and of the food [37,38]. From this point of view, cheese can be considered a complex food matrix which undergoes several (bio)chemical and rheological changes during storage. For this reason, samples of cheese were chosen so as to account for different manufacturing procedures which could lead to different features of the derived matured cheeses. Indeed, as expected, several and different VOCs (aldehydes, free fatty acids and some ketones) found in cheeses derived from biochemical processes involved in their ripening. For this reason, only VOCs never reported as naturally present in cheese and clearly attributable to migration phenomena from cling-films were considered. Among them, only VOCs raising particular health or legal issues are discussed below. The effect of storage time and film type as well as that of light on VOC levels in wrapped cheeses was not always clearly inferable. Nonetheless, as expected, only cheese samples wrapped in PVC-based films contained 2-EH with the highest levels of being present in cheese samples stored for 20 days and kept in the dark (Figure 5). The release of this VOC during storage appeared quite linear and its content in wrapped cheeses almost doubled from 10 to 20 days dark storage. 2-Ethylhexanol can easily migrate from film to food and directive 2002/72/CE provides a SML equal to 30 mg kg\({}^{-1}\) food [31]. To verify this limit, cheese samples wrapped in PVC-based films and stored (10-d) in the dark, as well as the sample of Quartirolo stored 20 days under light, were submitted to quantitative determination of 2-EH following the method provided by the Community  
Figure 5: Levels of 2-ethylhexanol (2-EH) in PDO cheees wrapped in different cling-films and stored refrigerated for 10 and 20 days in the dark or under fluorescent light (data expressed as ng g\({}^{-1}\) of cheese). Reference Laboratory for Food Contact Materials ([[http://ihcp.jrc.ec.europa.eu/](http://ihcp.jrc.ec.europa.eu/)]([http://ihcp.jrc.ec.europa.eu/](http://ihcp.jrc.ec.europa.eu/))) [31]. All the cheese samples respected the SML stated by directive 2002/72/CE. Only limited data are available for ethylbenzene (EB, CAS 100-41-4) contents in non-packaged foods and, for instance, EB was detected in milk [39, 40]. Levels of EB in the studied wrapped cheeses are reported in Figure 6. Slight evidence of the effects of storage time and lighting can be argued for the migration of EB, which was not present in unwrapped cheeses. EB occurs in nature as a fraction of petroleum and is a synthetic chemical used as a precursor for styrene and polystyrene [39, 40]. It should be mentioned that EB is also a common pollutant of air where it can easily be found as a consequence of industrial emissions [40, 41]. On this basis, its presence in the studied cheese samples can be attributed to both migration and environmental pollution. However, levels of EB in the air surrounding the cabinet display were not monitored and, therefore, some of the EB found in cheeses could derive indirectly from air-to-film migration. Overall, the highest levels of EB were recorded in wrapped Provolone followed by Quatrirolo (Figure 6). Levels of ethylbenzene (EB) in PDO cheeses wrapped in different cling-films and stored refrigerated for 10 and 20 days in the dark or under fluorescent light (data expressed as ng g\({}^{-1}\) of cheese). Levels of EB in cheeses wrapped in PE-based film (PE 200) augmented with storage time, with darkness a promoting factor in raising EB levels in chees. The enhancing effect of darkness and time was evident also for Provolone and Casera cheeses wrapped in PVC films (812 and 818). On the contrary, a positive role of darkness only can be inferred for Taleggio and Quatrirolo samples, since the prolongation of storage time decreased the EB levels in cheeses stored in absence of light.