On January 27, 2014 the peer-reviewed journal Food Control published online the article on “Plasticizer residues by HRGC–MS in espresso coffees from capsules, pods and moka [sic] pots” evaluating plasticizer chemicals migrating into coffee. The aim of the study by Giuseppa Di Bella and colleagues the Università di Messina, Italy was to gain an overview of plasticizer migration into coffee by comparing various coffee preparation system like “mocha”, “espresso”, pods and capsules. Plasticizers are used in plastic materials made from polycarbonate (PC), high and low-density polyethylene (HDPE, LDPE), polystyrene (PS), and polypropylene (PP) to affect properties like flexibility, color, resistance and durability. Not being covalently bound to the food contact materials’ (FCM) matrix, small chemicals like plasticizers can migrate into foodstuff over time. This process of migration is increased by e.g. temperature, physical stress and lipophilic foodstuff. Many plasticizers are linked to endocrine activity and are therefore considered potentially hazardous even at minute concentrations.
The aim of the study by Di Bella and colleagues was threefold: 1. Measuring plasticizer in coffee prepared in coffee machines used with pods and caps. These results were compared to mocha coffee pots using a new sealing ring, the only polymer part of the machine in contact with coffee. 2. Assessing migration from coffee powder into brewed coffee. 3. Evaluating levels of exposure, potential risk and reliable intake data, comparing those values with food safety regulations in the EU. The researchers tested 30 coffee types, of which 12 were pods sealed in a protective atmosphere in laminated foil pouches and 18 were 3 distinct types of capsules: (A) PS with PE aluminum sealing cap, (B) PE with PE closing, and (C) PE capsule sealed with micro-perforated film in LDPE. For comparison, roasted coffee for mocha coffee pots was used. For each coffee a 25 ml sample, the equivalent to an Italian espresso coffee, was collected and the coffee powder (5 – 7 g) itself was also analyzed for plasticizer content. Extraction of samples was carried out by solid phase extraction (SPE) and analysis was performed with high resolution gas chromatography coupled to a mass spectrometer (HRGC-MS).
The researchers found measurable levels of chemicals like dimethylphthalate (DMP; CAS 131-11-3), diisobutylphthalat (DiBP; CAS 84-69-5), diethyladipate (DEHA; CAS 141-28-6) , di(2-ethylhexyl)sebacate (DEHS; CAS 122-62-3), DiBP, dibutylphthalate (DBP; CAS 84-74-2) and di(2-ethylhexyl)phthalate (DEHP; CAS 117-81-7), and di-2-ethylhexyladipate (DEHA; CAS 103-23-1). None of the concentrations in the 25 ml coffee samples were particularly elevated and none of them were found to be over the regulatory threshold applicable in the European Union (EU). Hence, the authors conclude that drinking coffee prepared with capsules, pads and mocha pots is not a major source of plasticizers compared to other sources. However, it might be a potentially relevant source for people drinking many coffees daily; the highest concentration of DEHP found (52 µg L-1) equals an exposure to the low amount of 1.3 µg DEHP per 25 mL coffee serving. Lately data were published from the Norwegian Mother and Child Cohort Study (Sengpiel et al., 2013) including about 90’000 pregnant women. The results indicate that caffeine consumption correlates with lowered birth weights. The effect of other chemicals, even at minute concentrations, has not yet been assessed on a broad basis. Also the effects of mixture toxicities, in particular their effects on developing children, is not well assessed.
The researchers conclude that mean plasticizer intake from espresso coffee for capsules stems from DEA and DMP, for pods from DMP and for mocha from DMP and DEHA in this study. Comparing the levels of plasticizers found with levels described in European Food Safety Authority (EFSA) opinions (EFSA, 2005a, 2005b) indicates that all levels are to be considered not to be of concern. Classical toxicological assessments, however, do not evaluate mixture toxicity.
Di Bella et al. (January 27, 2014). “Plasticizer residues by HRGC–MS in espresso coffees from capsules, pods and moka pots”. Food Control.
Sengpiel et al. (2013). “Maternal caffeine intake during pregnancy is associated with birth weight but not with gestational length: results from a large prospective observational cohort study”. BMC Medicine.
EFSA (2005a). “Opinion of the Scientific Panel on Food Additives, Flavourings, Processing Aids and Material in Contact with Food (AFC) on a request from the Commission related to di-butylphthalate (DBP) for use in food contact materials”. The EFSA Journal, 242.
EFSA (2005b). “Opinion of the Scientific Panel on Food Additives, Flavourings, Processing Aids and Materials in Contact with Food (AFC) on a request from the Commission related to bis(2-ethylhexyl)phthalate (DEHP) for use in food contact materials”. The EFSA Journal, 243.