Do food packaging chemicals migrate into foods – is this an issue?

Do food packaging chemicals migrate into foods – is this an issue?

With so much food being “ready to eat” there is a large amount of food packaging which has been created to transport this food – from plastics to cardboard to organic materials but do the chemicals within the packaging leak into the food?  The New Zealand Ministry of Primary Industries (MPI) undertook a study to look at this question1.  The primary objective was to identify any dietary risk from the migration of packaging chemicals into New Zealand foods.

What are phthalates?

Phthalates are a group of chemicals used in the manufacture of plastic products.  They are a colourless and odourless chemical applied to increase the transparency, durability, flexibility and longevity of plastics products.  There are associations with phthalates affecting the metabolism, hormones and neurological systems of humans.

  • Toddler and baby foods sampled were free of food packaging chemicals.
  • MPI consider “there is negligible food safety risk” from chemicals in food packaging leaching into food.
  • Pizza and corn chips contained levels of phthalates above Specific Migration Levels

What did MPI do?

MPI evaluated 74 samples of packaged and takeaway foods.  Using chromatography2 (liquid and gas) and mass spectrometry3 they looked for 15 phthalate esters and 11 printing inks/photoinitiators.

FP002 phthalates found
Fifty-eight of the samples contained no phthalates, of the remaining 16 samples, containing phthalates, only two samples exceeded the Specific Migration Level outline by the EU regulation

Sixteen of the 74 samples contained three phthalates moieties and 11 samples4 contained five printing inks/photoinitiators contaminants.

Only two samples contained phthalates at a level higher than a Specific Migration Limit (SML) as set out in the European Union regulation (EU No 10/2011).  These were one (out of two) sample of corn chips in a plastic/foil bag and one (out of five) sample of pizza in a cardboard box.  The DEHP found in the corn chips was nearly three times the SML (4.4 mg/kg where 1.5 mg/kg is the SML) and the DEHA found in pizza was one and a half times the SML (27 mg/kg where 18 mg/kg is the SML).

No samples of the printing inks/photoinitiators were greater than the recommended levels5.

To make the results more meaningful …

MPI applied all affected food items to a diet scenario to calculate how much of each substance would be eaten in a regular diet.   A conservative approach was taken and the dietary scenario applied the highest concentration of contaminant found in a food e.g. the diet scenario had the pizza level of DEHA at 27 mg/kg even though only one sample in five contained DEHA.

From the diet scenario …

The ingested levels of printing inks/photoinitiators were below a health-based guidance value for all of the population but not the phthalates.

While the ingested phthalate levels were below a health-based guidance value for an adult, it was not always the case for teenagers, children and toddlers who are smaller.  MPI concluded, “there is a negligible food safety risk” as the worst-case dietary scenario was used to calculate that risk e.g. very high pizza consumption over a lifetime.  Yes, and this might be so in a normal dietary situation but is there “risk” in an extreme scenario of young children with a diet high in the ‘particular’ corn chips or the ‘particular’ pizza with high levels of phthalates?

The identities of the food products were not provided but here is a list of the 74 food samples tested.  The foods with no chemical migration have been highlighted in green.

FP002 Study Foods
List of the 74 foods tested by Ministry of Primary Industries. The highlighted samples contained no measurable phthalates. At least one of the unhighlighted samples contained phthalates. Table from MPI report.

If you are concerned about chemical migration …

MPI offers suggestions on how to reduce risk in plastic packaging6

  • Use the right plastic for the job and follow the manufacturer’s instructions
  • Heat changes plastic wrap, so avoid cling film touching food during cooking
  • Defrost meat wrapped in plastic or on plastic trays at low temperatures.
  • Avoid dented food or drink cans
  • Don’t heat food in supermarket bags
  • Use supermarket bags with the printing on the outside
  1. Ministry of Primary Industries. Occurrence and risk characterisation of packaging chemicals in New Zealand foods. MPI Technical Paper No: 2017/61. Wellington: Ministry of Primary Industries, 2017.
  2. Chromatography separates the chemical molecules.
  3. Mass Spectrometry identifies and quantifies the chemical molecules.
  4. 1 DETX, 5 BP, 1 HMPP, 1 IR184, 1 BP and IR184, 1 HMPP and IR184, 1 BP, DMPAP and IR184.
  5. Recommended levels: one of the five printing inks/photo initiators detected had an EU SML, for the remaining four a threshold of toxicological concern approach was adopted to assess the risk.
  6. Ministry of Primary Industries. Internet: (accessed 3 February 2022).

Keywords: MPI, Ministry of Primary Industries, food packaging, chemical migration, New Zealand.

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