Identification and Quantitation Studies of Migrants from BPA Alternative Food-Contact Metal Can Coatings.

Bisphenol A (BPA)-based epoxy resins have wide applications as food-contact materials such as metal can coatings. However, negative consumer perceptions toward BPA have driven the food packaging industry to develop other alternatives. In this study, four different metal cans and their lids manufactured with different BPA-replacement food-contact coatings are subjected to migration testing in order to identify migratory chemical species from the coatings. Migration tests are conducted using food simulants and conditions of use corresponding to the intended applications and regulatory guidance from the U.S. Food and Drug Administration. Extracts are analyzed by gas chromatography mass spectrometry (GC-MS) and high resolution GC-MS. The migratory compounds identified include short chain cyclic polyester migrants from polyester-based coatings and bisphenol-type migrants including tetramethyl bisphenol F (TMBPF), tetramethyl bisphenol F diglycidyl ether (TMBPF DGE), bisphenol F (BPF), bisphenol C (BPC), and other related monomers or oligomers. The concentration of the migrants is estimated using an internal standard, and validated trimethylsilyl (TMS) derivatization GC-MS methods are developed to specifically quantify TMBPF, BPF, BPC, and BPA in the coatings. The results will aid the safety evaluation of new food-contact material coating technology based on TMBPF chemistry and will provide an important reference for the industry in identifying and quantifying non-BPA coating-borne migrants.

Identification and Migration Studies of Photolytic Decomposition Products of UV-Photoinitiators in Food Packaging.

UV-curable inks, coatings, and adhesives are being increasingly used in food packaging systems. When exposed to UV energy, UV-photoinitiators (PI's) present in the formulations produce free radicals which catalyze polymerization of monomers and pre-polymers into resins. In addition to photopolymerization, other free radical reactions occur in these systems resulting in the formation of chemically varied photolytic decomposition products, many of which are low molecular weight chemical species with high migration potential. This research conducted model experiments in which 24 commonly used PI's were exposed to UV-energy at the typical upper limit of commercial UV-printing press conditions. UV-irradiated PI's were analyzed by gas chromatography-mass spectrometry (GC-MS) and electrospray-mass spectrometry (ESI-MS) in order to identify photolytic decomposition products. Subsequently, migration studies of 258 UV-cure food packaging samples were conducted using GC-MS; PI's and photolytic decomposition products were found in nearly all samples analyzed. One hundred-thirteen photolytic decomposition products were identified. Eighteen intact PI's and 21 photolytic decomposition products were observed as migrants from the 258 samples analyzed, and these were evaluated for frequency of occurrence and migratory concentration range. The most commonly observed PI's were 2-hydroxy-2-methylpropiophenone and benzophenone. The most commonly observed photolytic decomposition products were 2,4,6-trimethylbenzaldehyde and 1-phenyl-2-butanone. This compilation of PI photolytic decomposition data and associated migration data will aid industry in identifying and tracing non-intentionally added substances (NIAS) in food packaging materials.

Volatile 1-octen-3-ol increases patulin production by Penicillium expansum on a patulin-suppressing medium.

1-Octen-3-ol is one of the most abundant volatile compounds associated with fungi and functions as a germination and growth inhibitor in several species. By investigating its effect on the biosynthesis of patulin, a mycotoxin made by Penicillium expansum, it was found that a sub-inhibitory level of volatile 1-octen-3-ol increased accumulation of patulin on a medium that normally suppresses the mycotoxin. Transcriptomic sequencing and comparisons of control and treated P. expansum grown on potato dextrose agar (PDA; patulin permissive) or secondary medium agar (SMA; patulin suppressive) revealed that the expression of gox2, a gene encoding a glucose oxidase, was significantly affected, decreasing 10-fold on PDA and increasing 85-fold on SMA. Thirty other genes, mostly involved in transmembrane transport, oxidation-reduction, and carbohydrate metabolism were also differently expressed on the two media. Transcription factors previously found to be involved in regulation of patulin biosynthesis were not significantly affected despite 1-octen-3-ol increasing patulin production on SMA. Further study is needed to determine the relationship between the upregulation of patulin biosynthesis genes and gox2 on SMA, and to identify the molecular mechanism by which 1-octen-3-ol induced this effect.