Epoxy-based lacquers or vinylic organosol (PVC) materials are commonly used for coating the inside of food cans to reduce food spoilage and to prevent degradation of the food can. These lacquers can release bisphenol A (BPA) and bisphenol F (BPF), and may also contain bisphenol A diglycidyl ether (BADGE) or bisphenol F diglycidyl ether (BFDGE), and Novolac glycidyl ether (NOGE) as well as oligomers and derivatives into the packed foods. These compounds may break down to other compounds during storage (chlorohydroxy and hydrolysis derivatives).
Bisphenol A (BPA)
BADGE & BFDGE
Novolac Glycidyl Ether (NOGE)
Phthalates
BPA is an artificial estrogen compound used to make plastic products more rigid and clear plastic food containers. It is most commonly used as a sealant lining in the epoxy of food and beverage cans to reduce food spoilage and also as a dental sealant. Recently, its presence in consumer goods has been linked to cancer, miscarriage, insulin-resistance, birth defects and more. BPA in animal studies was shown to have toxic effects at low levels.
| Bisphenol A diglycidyl ether (BADGE) and Bisphenol F diglycidyl ether (BFDGE) |
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These compounds are commonly found in oily foods since the oil extracts the coating during thermal processing and protects the epoxy group from hydrolysis.
Novolac Glycidyl Ether (NOGE) Novolac is the technical name for complex mixtures obtained by reaction of phenol with formaldehyde under acidic conditions. When Novolac is reacted with epichlorohydrin, HCl is eliminated forming Novolac glycidyl ethers (NOGE). An important difference between NOGE and BADGE is the number of reaction products that are formed during the reaction between phenol and acetone or formaldehyde. Acetone reacts with phenol only at the para position forming bisphenol-A, a single compound that is the precursor to BADGE. However, formaldehyde can react with phenol at the para and the two ortho sites creating three bisphenol-F isomers, the precursors to NOGE. Besides the three possible 2-ring bisphenol-F isomers, up to three phenols can be bonded to each phenol enabling oligomerization through the methylene groups. The result is that NOGE is a complex mixture of 2-, 3-, 4-, 5- and 6-ringed compounds.
Phthalates or phthalic acid diesters are plasticizers minimally used in the food industry, but are found most often in lubricating oils and many household consumer products such as children’s toys, medical equipment, etc. Applications in the food industry are limited to adhesives and printing inks. Phthalates are fat-soluble endocrine disruptors and there is some concern that exposure may impact negatively on reproductive health. Due to their persistence in the environment, they are commonly found in groundwater, lakes, streams, rivers and drinking water.
