High sensitivity determination of mineral oils and olefin oligomers in cocoa powder and related packaging: Method validation and market survey

Abstract

Mineral oil saturated (MOSH) and aromatic hydrocarbons (MOAH) and related hydrocarbons of synthetic origin are both packaging and processing contaminants of health concerns. The purpose of this work was to validate a method for their rapid and high-sensitivity determination in cocoa powder, using it to monitor the presence of these contaminants in products purchased in Italy and North Macedonia. Relevant primary and secondary packaging was also analyzed. Method performance was good (average recovery 74-106 %, with RSD ≤13 %). In addition to pre-existing contamination, oligomeric polyolefin hydrocarbons (POH) from primary plastic packaging and MOSH/MOAH from recycled cardboard secondary packaging were found in many samples. Total MOSH/POH ranged from 1.2 to 69.2 mg/kg (on average 20.9 mg/kg), exceeding the German benchmark levels of 9 mg/kg in half of the samples from Italy and in all those from Northern Macedonia. Most of the samples had MOAH >0.5 mg/kg.

Keywords: Cocoa powder; Microwave-assisted saponification (MAS); Mineral oil contamination; On-line HPLC-GC-FID; Packaging migration; Polyolefin oligomers.