The present study has shown that migration tests using 20% ethanol as food simulant at the accelerated test conditions of 10 d at 60 °C highly overestimate the migration into real food (in this case, energy drinks) at the end of shelf life. The migration of bisphenol A into 20% ethanol at 60 °C is a factor of >67 (sample 1) or >35 (sample 2), respectively, higher than the migration into real beverages at the end of shelf life. This overestimation of the migration is due to swelling of the epoxy can coating by the ethanolic food simulant. Water-based food simulants, or the energy drink itself, is less swelling and, therefore, the migration into real foods is much lower and, in the case of this study, below the experimental detection limits. Migration into 20% ethanol at 60 °C results in a migration value which is close to the total migration (Figure 1
), which indicates that the applied contact conditions represent, more likely, extraction conditions than migration conditions. The test conditions 10 d at 40 °C also turned out to be overestimative, though to a lesser degree. However, compared to real food, the migration is overestimated by a factor of 4, at minimum. The overestimative effect due to swelling should be considered when performing compliance tests for coated cans with 20% ethanol as simulant. However, it should also be noted that in none of the performed overestimative migration tests was the specific migration limit of bisphenol A of 50 µg/L, according to Regulation (EU) No 10/2011, exceeded. The migration potential of bisphenol A in the can coating, which assumes a complete transfer of bisphenol A into the beverage, was only 10.2 µg/L (sample 1) and 5.3 µg/L (sample 2), respectively, which is a factor of approximately 5 and 10 below the specific migration limit of bisphenol A. Prediction of the migration of bisphenol A from its residual concentration in the epoxy can coating by use for migration modeling, with the published modeling parameters of PET [8
], results in a much more realistic migration value compared to the migration into swelling ethanolic simulants like 20% ethanol. The determination of bisphenol A in non-filled cans is therefore a useful test for production control. Empty bottle coatings might be tested for their residual bisphenol A concentration. Assuming total transfer of bisphenol A into the can-packed beverages, the worst-case concentration can be compared to the legal specific migration limit of 50 µg/L. If the migration potential of bisphenol A exceeds the specific migration limit, migration modeling, as applied in this study, can be used for the prediction of the migration at the end of shelf life. Such a procedure avoids that food simulants and elevated storage conditions, like 20% ethanol for 10 d at 60 °C, result in non-realistic, very overestimative migration values for bisphenol A.