# Chemical Migration from Wine Contact Materials
## 3 Chemical Migration, European Regulation, and International Organization of Vine and Wine  
Migration of chemical substances is a diffusion process subject to both kinetic and thermodynamic control. The parameters that affect the phenomenon of migration are related to (i) the type of FCM, (ii) the food/beverage content, and (iii) the conditions (time and temperature) of contact [38]. In more detail, the migration of chemical substances depends on the composition of the FCM, which is the source of the migrating compounds. The identity and concentration of these compounds present affect their migration into the food/beverage. In addition, the type of FCM is crucial in terms of thickness, permeability, porosity, degree of crystallinity, and number and type of layers that it consists of, affecting the diffusion of chemicals in the material [38]. In impermeable materials like metals, glass, and ceramics, in the absence of another type of chemical interaction, migration can occur only from the contact surface and not from the interior of the material [38]. On the contrary, permeable materials like rubbers, elastomers, and soft and flexible plastics exhibit limited resistance to mass transfer from their interior. In addition to this, porous materials like paper and board, which consist of open networks of fibers, may permit the transfer of chemical compounds of low molecular weight [38]. The nature of the food (aqueous, acidic, alcoholic, etc.) defines whether there will be an interaction with the contact material and eventually affects the migration that will occur. For example, the interaction between an uncoated metal surface and an acidic beverage like wine could lead to corrosion of the surface and the release of metal into the beverage. Finally, the conditions of contact include the contact surface/food mass ratio, temperature, and duration [38; 39]. The safety of all types of materials and articles intended to come into contact with food is secured by the Framework Regulation (EC) 1935/2004 [40], according to which the manufacturing of these materials and articles should be compliant with good manufacturing practice, ensuring that under typical and predictable conditions they do not transfer any constituents to food in quantities that might endanger human health or cause unacceptable changes in the composition of the food, or cause deterioration in the organoleptic characteristics of the food. Specifically, the use of plastic materials and articles intended to come into contact with food is further regulated according to Commission Regulation (EU) No. 10/2011 [41]. On the one hand, the compliance of materials and articles not yet in contact with food is demonstrated by migration testing under specific conditions of food simulant, time, and temperature. By definition, in the EU, the alcohol content of wine is generally between 8.5% (\(v/v\)) and 15% (\(v/v\)), while in specific cases, it can be as low as 4.5% (\(v/v\)) or as high as 20% (\(v/v\)) [42]. Liqueur wines (fortified wines) and aromatized wines can reach an alcohol content of up to 22% (\(v/v\)) [42; 43]. Based on the alcohol content, the food simulant that is assigned to be used during the migration test by the Regulation is ethanol 20% (\(v/v\)) for wines and ethanol 50% (\(v/v\)) for liqueur wines and wine-based products with an alcohol content above 20%. In addition, the pH values of wine can range between 2.9 and 3.8 [44]. Therefore, based on these pH values, the food simulant that is assigned for the migration test is acetic acid 3% (\(w/v\)). The extract of the food simulant is analyzed using appropriate analytical methods. On the other hand, for materials and articles already in contact with food, the testing includes analysis of the food that has been treated according to the instructions of the packaging, homogenized, and analyzed with appropriate analytical methods. The analytical method to be applied depends on the compounds that are investigated. But which substances can possibly migrate?