Number 169 January 1999
MAFF UK - DIISOPROPYLNAPHTHALENES IN FOOD PACKAGING MADE FROM RECYCLED
PAPER AND BOARD
Index to MAFF UK Food Surveillance Information
60: MAFF, UK - Phthalates in Paper
and Board Packaging (May 1995)
66: MAFF, UK - Grease Proofing
Agents in Paper and Board (June 1995)
72: MAFF, UK - Curing Agents in
Carton Board Food Packaging (July 1995)
90: MAFF, UK - Survey of Paper and
Board Food Contact Materials for Residual Amine Monomers from Wet
Strength Agents (May 1996)
139: MAFF, UK - Survey of
Pentachlorophenol in Paper and Board Packaging used for Retail Foods
174: MAFF, UK - Survey of Retail
Paper and Board Food Packaging Materials for Polychlorinated Biphenyls
(PCBs) (April 1999)
186: MAFF, UK - Epoxidised Soya
Bean Oil Migration from Plasticised Gaskets (September 1999)
A survey was carried out on the presence of the solvent
diisopropylnaphthalenes (DIPNs) in food as part of JFSSG's continuing
investigation into chemical migration from food packaging materials made
from board. DIPNs could be present in some recycled packaging. The
objectives were to test whether DIPNs were present in food packaging and,
if so, whether they were also present in packaged food. The survey was
carried out in three stages. In the first stage 51 samples of board made
from recycled paper and board were obtained from paper mills and analysed.
In the second stage 34 samples of food packaging, made from such board,
were obtained and analysed. In the third stage 11 samples of food which
had been packaged in material containing the highest levels of DIPNs were
DIPNs were detected in all samples of board from mills at up to 33 mg/kg
and in most (30 out of the 34) samples of retail packaging at up to 44
mg/kg. They were also detected in six samples of food at levels up to 0.36
mg/kg and in one sample at 0.89 mg/kg. Four food samples did not contain
DIPNs. Some of the packaging samples contained an intervening film wrap in
the packaging between the food and the recycled board but, judging by the
results obtained, this did not appear to influence migration of DIPNs.
The findings of this survey were considered by the Committee on Toxicity
of Chemicals in Food, Consumer Products and the Environment (COT) at its
meeting in February 1998 and again at its meeting in October 1998. The
Committee were also provided with estimates of intake and were asked to
consider the available toxicological data on DIPNs. In February the COT
concluded that, apart from one teratology study, the toxicological
information on DIPNs is inadequate and agreed that additional mutagenicity
and long-term studies are needed. The Committee recommended that these
studies should be submitted within three years and that, in the meantime,
it would be prudent to ensure that levels of DIPNs in food packaging made
from recycled paper and board should be kept as low as reasonably
practicable to minimise migration into food. The Committee confirmed this
advice at its October meeting.
The Food Advisory Committee (FAC) endorsed the recommendations of the
COT. The FAC also recommended that a further survey should be undertaken,
in due course, to check on the progress made in reducing the levels found
Recycled paper used in making board may include carbonless copy paper
(also known as self-duplicating paper). DIPNs are used as the solvent for
the colour former in carbonless copy paper. Not all of the DIPNs may be
removed by the treatment of the recycled fibres. Some may be present in
the finished board and thus could migrate into food.
The purposes of the survey were to determine whether DIPNs were present
in samples of board made from recycled paper and board and used in food
packaging in the UK, and, if so, whether DIPNs were also present in the
packaged foods. Studies of DIPNs in food have taken place in Italy,1
where DIPNs were found in rice at levels of up to 1.24 mg/kg, and Germany,2
where DIPNs were detected in a wide range of foods at levels of up to 4
Fifty-one samples of board with a range of recycled fibre contents were
obtained from paper mills and analysed for DIPNs. In addition, three
samples of virgin fibre boards, which did not contain recycled fibres,
were analysed to provide a measure of possible background contamination
and/or cross-contamination in production. All samples were wrapped in
aluminium foil and stored separately. Thirty-four samples of retail foods
in board packaging were purchased. Where possible these samples were
selected where information from manufacturers or packaging labels
suggested that the packaging could contain recycled fibres. Eleven samples
of foods where the packaging contained the highest levels of DIPNs were
The method of analysis involved the isolation of DIPNs by
distillation/concentration, with determination by gas chromatography-mass
spectrometry using d10-anthracene as an internal standard. Recovery of
DIPNs was checked by spiking samples of GFC filter paper at 0.5
micrograms/dm2 and food at 0.1 mg/kg, and was 90-110 percent.
This methodology was developed by the contractor, RHM Technology Ltd., for
the purpose of this survey. The in-house estimate of the repeatability
standard deviation for this method was 0.06.
The effective removal of residual DIPNs from the distillation apparatus
was difficult, despite repeated cleaning between extractions. In all cases
therefore, the limit of detection was determined by the presence of DIPNs
in the blanks and not by instrumental sensitivity or sample-based
interferences. The limit of detection of each commodity, estimated from
the analysis of procedural blanks, was set as the mean plus three sample
standard deviations. The limits of detection were 0.3 micrograms/dm2
(0.11 mg/kg) for board samples and 0.03 mg/kg for food samples.
Results and Interpretation
Samples of board from paper mills were analysed first to provide a
picture of the range of levels and incidence of contamination by DIPNs.
DIPNs were detected in all of them (Table 1a),
including three virgin board samples (Table 1b).
The presence of DIPNs in virgin board was not due to cross-contamination
of samples in the survey. The levels detected are real values being much
above the blank values obtained at the time of analysis. It is possible
that there was cross-contamination in manufacture as the virgin board
originated from a mill which also manufactured recycled board.
Samples of retail packaging and packaged foods were then analysed to
check on the levels and incidence in this packaging, and then for those
samples in which levels of DIPNs were highest in packaging, to measure the
levels of DIPNs in the respective food samples. DIPNs were detected in 30
out of 34 retail packaging samples for foods at up to 44 mg/kg (160
micrograms/dm2) (Table 2). The foods
contained in eleven packaging samples with the highest levels of DIPNs
were then analysed. Seven samples contained DIPNs, at levels of 0.06 mg/kg
to 0.89 mg/kg (Table 3). Six out of the seven
samples contained DIPNs at or below 0.36 mg/kg. There was not a clear
correlation between DIPN levels in food samples and in the packaging used
for them. No conclusions can be drawn about other products not tested in
The details for each of the retail samples, including brand names and
'best before end' dates, are reported in Table 4.
Where samples of retail packaging were found to contain DIPNs, the
respective companies were invited to comment on their individual results.
The comments provided are attached at Annex 1.
DIPNs are carried through the papermaking process from the feedstock to
the finished product in varying amounts. This variability may be owing to
factors such as the nature of the fibres, the percentage of carbonless
copy paper in the feedstock and the effectiveness of cleaning processes.
The results of this survey are consistent with work overseas.1,2
This survey shows that the use of board packaging, made from recycled
paper and board which incorporates carbonless copy paper, can result in
migration of DIPNs into food, including dry foodstuffs. This observation
will be followed up in JFSSG research starting soon on chemical migration
into dry foods. It might be expected that such migration would be reduced
if a board liner or film overwrap were placed between the food and the
board. However, from the relatively few samples examined in this part of
the survey there would not appear to be a simple relationship between the
presence of an intervening film wrap in the packaging and reduced levels
of DIPNs in the packaged foods.
- Sturaro, A., Parvoli, G., Rella, R., Bardati S.,
and Doretti, L. (1994). Food contamination by diisopropylnaphthalene
from cardboard packages. International Journal of Food Science and
Technology, 29, 593-603.
- Bebiolka, H., and Dunkel, K. (1997). Übergang
von di-iso-propyl-naphthalin aus karton-verpackungen auf lebensmittel.
Lebensmittelchemie 51, 53-61.
The report of the survey is held in the MAFF Library at Nobel House, 17
Smith Square, London SW1P 3JR (Tel: +44 (0) 171-238-6573).
This survey was completed before the adoption of the guidelines for
reporting survey results announced in the January 1999 issue of the
Food Safety Information Bulletin.
Further enquiries should be addressed to:
Mr Patrice Mongelard
Food Contact Materials Unit
Additives and Novel Foods Division
Room 213, Ergon House
17 Smith Square
London SW1P 3JR
Tel: +44 (0) 171-238-6225
Fax: +44 (0) 171-238-6124
COMMENTS FROM THE MANUFACTURERS OF THE FOOD BRANDS WHERE DIPNs WERE
DETECTED IN EITHER THE PACKAGING OR THE FOOD.
Kellogg Marketing & Sales Company (UK) Ltd (Talbot Road,
Manchester, M16 0PU)
(Commenting on sample 18572)
Kellogg is committed to providing consumers with innovative
grain-based foods that deliver superior nutrition, taste, convenience,
quality and value, and are safe to enjoy.
We note that the level of DIPN reported in the MAFF survey for our
product does not present a risk to health. Furthermore, testing of the
food indicates the low level of contamination came exclusively from the
cartonboard. We will continue to work with our packaging suppliers on this
industry-wide issue to ensure that any DIPN in our recycled cartonboard is
at the lowest possible level.
McDonald's Restaurants Ltd
(Commenting on samples 18522, 18523 and 18524)
McDonald's works very closely with all food and packaging suppliers
to meet the highest standards of food safety. We also act responsibly
towards the environment by the selective inclusion where appropriate of
recycled fibres that have been specifically developed for use in food
The very low level of DIPN found in one sample of food confirms our
own test results, namely that they are already extremely low. Our
suppliers have programmes in place to minimise the DIPN content in
packaging and will continue to develop materials and technologies to
effect further reductions.
(Commenting on sample 18579)
We would wish to emphasise that we only use virgin board, guaranteed
by our supplier, and our printing inks do not contain DIPN. Our own
analysis of this packaging reveals no DIPN whatsoever.
In view of this, and the very low level of DIPN you found, we can
only assume this arose due to cross-contamination. Like yourselves, we do
not have any sure knowledge as to how this might have happened. We will be
making every effort to investigate this in more detail.
Nestlé UK Ltd
(Commenting on sample 18577)
Nestlé UK Ltd,
- supports recommendations of the Committee on Toxicology and the
Food Advisory Committee that more studies are required to establish
better toxicological data on DIPN and where necessary all reasonable
steps should be taken to reduce levels of DIPN found in food.
- Recognises that while very low levels of DIPN were detected in
board packaging used in Buitoni Lasagne, testing was not carried out on
the food itself. We are currently reviewing the use of recycled board in
the packaging concerned and will take appropriate steps to further
minimise the risk of migration into the food.
Perfect Pizza Limited
(Commenting on sample 18961)
Perfect Pizza Limited note the results of the analysis of our pizza
This is the first notification received that there may be any issue
with DIPN, and we note that there are currently no recommended levels.
However Perfect Pizza Limited regard food safety as of paramount
importance and in view of the COT recommendations to carry out long term
studies, agree that it would be prudent to ensure DIPN levels are kept as
low as reasonably practical, and are therefore working with our suppliers
to reduce DIPN levels as soon as possible.
Pizza Hut (UK) Ltd
(Commenting on sample 18960)
Pizza Hut (UK) Ltd and their suppliers do not knowingly use base raw
material containing DIPN nor is it intentionally added during the paper or
board making process. It is understood that DIPN may be found in both
recycled fibres and virgin fibres, which is of course of concern to Pizza
Hut (UK) Ltd.
The safety of our customers is always top priority and as a result
of the findings we have now instigated a full testing programme for DIPN
on all items of packaging in contact with food.
Following on from the survey and testing of the packaging, we, in
partnership with our suppliers, are to formulate a programme on the
development of processes for minimising DIPN in the finished product. The
activities of this project will probably depend on the outcome of the
current work being carried out by the German paper industry, where the
major sources of DIPN in the industry are being identified and we eagerly
await the outcome of the presentation of the paper to the expert group of
the Council of Europe with regard to toxicology to humans and the setting
of sensible limit values for DIPN.
Sainsbury's Supermarkets Ltd
(Commenting on samples 18806, 18809 and 18810)
We note that the reported levels of DIPN in all of the examined
Sainsbury's packaging samples were amongst the lowest reported levels in
your survey, and that other products in your survey contained 100 times as
We believe this issue is first and foremost the proper concern of
the Paper and Board Manufacturers, as the suggested source of
contamination, the use of recycled paper fibre, is not under the control
of the users of packaging materials, such as ourselves.
(Commenting on sample 18808)
All Tilda rice cartons are manufactured from coated board containing
only virgin fibres and are printed using inks and varnishes which do not
include DIPN in their formulations.
The 0.9 mg/kg DIPN found in the survey for Tilda Basmati & Wild
Rice is entirely consistent with the levels found in the survey for virgin
boards direct from mills which also produce recycled board.
(Commenting on sample 18573)
Weetabix Ltd. is reassured that DIPN was not detected in our
product. We believe that, although it was found in the outer carton, the
inner wrap protected the product by functioning, as designed, as a
barrier. As DIPN is a new concern, we are asking our suppliers to
establish the permeability of their packaging films to DIPN, so that we
can use the most appropriate film.
We welcome an early clarification of the toxicity of DIPN and
support any action necessary to remove it from recycled food packaging
material, so that the environmentally responsible use of such material can
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These pages were last updated on 22 Dec 1998