Number 168 December 1998
MAFF UK - PHTHALATES IN INFANT FORMULAE - FOLLOW-UP SURVEY
See also:
60: MAFF UK - Phthalates in Paper
and Board Packaging (May 1995)
62: MAFF UK - Multi-element
Analysis of Infant Foods (May 1995)
82: MAFF UK - Phthalates in Food
(March 1996)
83: MAFF UK - Phthalates in Infant
Formulae (March 1996)
93: MAFF UK - Multi-Element Analysis
of Infant Foods - Follow-up Survey (August 1996)
167: MAFF UK - Plant Oestrogens in
Soya-Based Infant Formulae (November 1998)
190: MAFF UK - Metals and other
elements in infant foods (November 1999)
Summary
The levels of phthalates measured in a recently completed survey of
retail samples of infant formulae are considerably lower than those
reported for a previous survey in 1996. The dietary exposure to individual
phthalates by infants consuming these formulae are also estimated to be
much lower than those reported in 1996 and are well below relevant safety
guidelines (Tolerable Daily Intakes) where these have been set. As in
1996, these data indicate that the phthalate levels in infant formulae are
unlikely to pose any health risks to infants. The Food Advisory Committee
has agreed that the increased margins of safety shown by the 1998 data are
reassuring. Parents are not advised to change the feeding regimes of their
infants or to switch brands on the basis of these results.
Four of the 7 individual phthalates analysed were not detected in any of
the 39 samples of infant formulae (powdered and ready-to-feed).
Concentrations of the remaining 3 phthalates were in the range less than
0.01-0.44 mg/kg (as purchased). Di-2-ethylhexyl phthalate (DEHP) was the
most abundant individual phthalate, as in 1996. Total phthalate
concentrations ranged between less than 0.1-0.6 mg/kg in powder samples
and less than 0.05-0.07 in liquid samples, more than 10 times lower than
reported for the 1996 survey.
Background
Phthalic acid diesters, commonly known as phthalates, are a group of
organic chemicals with a variety of industrial uses, including lubricating
oils, as plasticisers in a wide range of household and consumer goods and
as carriers for perfumes in cosmetics. Phthalate use in plastic food
packaging is limited, for example, to the manufacture of materials such as
some adhesives and some printing inks.
Phthalates may be released into the environment during their own
production and distribution, or during the manufacture, use, or dispersal
of the products in which they are used. Some phthalates occur naturally in
coal, crude oil and shale, although the contribution of such sources to
general environmental levels of phthalates is likely to be insignificant.1
As a result of their use and moderate resistance to degradation,
phthalates are widely distributed in the environment and are often found
at low levels in food.2 Phthalates are
soluble in fat and their presence in fat-containing foods is not
unexpected. A number of studies of fat-containing foods have suggested
that the presence of phthalates in food is due to general contamination of
the environment, rather than specific sources such as food packaging.3,4,5,6,7,8
In recent years, several naturally occurring and man-made chemicals,
including phthalates, have been reported to have oestrogenic properties.
[Oestrogens are the hormones which develop and maintain female bodily
characteristics]. There has been some concern that these chemicals,
usually referred to as endocrine disrupters, may have a detrimental effect
on human sexual development, although there has been no conclusive
evidence of a link between adverse trends in human reproductive health and
the presence of these chemicals. Further research is needed to confirm the
effect, if any, of such chemicals in man at the levels that may occur in
food and the environment. The UK Government is funding work in this area.
The toxicity of phthalates permitted for use in food contact materials
has been considered by the European Commission's Scientific Committee for
Food (SCF). Sufficient toxicological data were available for the SCF to
set Tolerable Daily Intakes (TDI), or temporary TDIs, for some
individual phthalates. Less information was available for the remaining
phthalates used in food contact materials and the SCF recommended a
temporary "group restriction" for those chemicals. The group
restriction is not a TDI but a precautionary limit set to guide the food
contact materials industry and enforcement authorities pending submission
of further toxicological data. In addition, the SCF's 1996 opinion9
on phthalates took account of the available studies on the potential
oestrogenic activity of these compounds. The SCF saw no reason to change
its current TDIs or its current temporary TDIs. The SCF has advised that
it considers it inappropriate to compare the estimated dietary exposure to
total phthalates, measured as dimethyl phthalate (DMP), with the SCF group
restriction for migration from food contact materials. This is because of
uncertainty about which unknown phthalates may be included in the
measurement of total phthalates as DMP and incomplete knowledge concerning
the toxicological profile of such mixtures.9
MAFF has previously carried out surveys for phthalates in samples
representing the typical diet (Total Diet Study; TDS).2
TDS samples consist of retail food products, prepared for consumption, and
then combined into composite samples in amounts reflecting their relative
importance in the typical UK diet. The survey, published in 1996, was
carried out on the 1993 TDS samples. Individual retail samples of a range
of fatty foods have also been analysed. Average dietary exposures to the
five individual phthalates analysed were estimated to be in the range
0.004-0.15 mg/person/day, while high level (97.5th percentile) dietary
exposure to the individual phthalates ranged from 0.009-0.30
mg/person/day. Taking into account the information then available on the
possible effects of phthalates (including reported oestrogenic activity),
the Department of Health advised that there were unlikely to be any health
risks to consumers from the estimated dietary exposures to individual
phthalates.
In 1996, MAFF also published results of a survey for phthalates in 12
composite samples of 15 brands of infant formulae.10
Phthalates were present at low levels in all samples tested. Again taking
into account the information available at that time on the possible health
effects of phthalates (including reported oestrogenic activity), the
Department of Health advised that the concentrations of phthalates then
found were unlikely to pose any health risks to infants fed these
products, a view which was supported by the independent expert Committee
on Toxicity of Chemicals in Food, Consumer Products and the Environment
(COT) and the SCF. The Food Advisory Committee (FAC) also considered those
results and endorsed the cautionary action taken by MAFF to ask
manufacturers to trace the source of phthalates in infant formulae so that
levels could be reduced. MAFF has now carried out a follow-up survey to
determine the levels of phthalates in infant formulae currently produced.
For the current survey, 39 retail samples (35 dry powders and 4
ready-to-feed liquids) of 14 different infant formulae products were
purchased from retail outlets in Norwich and London. Brands were selected
for inclusion on the basis of market share and the products sampled
account for more than 95 per cent of the overall market. The samples
included 19 samples of casein-dominant milk-based formulae, 14 samples of
whey-dominant milk-based formulae and 6 samples of soya-based formulae.
The sampling plan was drawn up in consultation with manufacturers to
confirm that it was based on market share and that the samples collected
reflected current production. The survey did not specifically investigate
the possibility of variation in phthalate levels with location as the
batches obtained in London or Norwich would have been on sale throughout
the UK.
Methodology
As with the 1996 survey, all samples were analysed at the CSL Food
Science Laboratory, Norwich.
The details of the analytical method and quality control criteria are
given in the final report of the survey which is available for public
access in MAFF's library.11 The levels
of 7 individual phthalates and the total phthalate content were determined
in each sample (Table 1). The total phthalate
concentration was determined as dimethyl phthalate (DMP), a measure which
includes, not only the 7 phthalate esters determined individually, but
also any other phthalates present.
Individual phthalates were analysed using liquid chromatography coupled
to mass spectrometry (LC-MS). LC-MS was used in preference to GC-MS to
determine individual phthalates as this methodology achieved lower and
less variable blank values than the GC-MS procedure. Total phthalates
(measured as DMP) were determined by gas chromatography coupled to mass
spectrometry (GC-MS).
The 7 individual phthalates determined are shown in Table
1 with an indication of the concentration at, or above, which
results were reported to the MAFF/Department of Health Joint Food Safety
and Standards Group (i.e. the reporting limit). Concentrations below these
assigned levels were reported as being less than the relevant reporting
limit value.
For di-isopropyl phthalate (DIPP), dipropyl phthalate (DPP), di-isobutyl
phthalate (DIBP) and benzyl butyl phthalate (BBP), the reporting limit was
the limit of detection of the analytical method. For di-isodecylphthalate
(DIDP), the measuring limit was impaired as the mixture of C10
isomers eluted as a rather broad envelope of peaks; the reporting limit
was again the limit of detection. For dibutyl phthalate (DBP),
di-2-ethylhexyl phthalate (DEHP) and total phthalate (as DMP), the
reporting limit was the limit of determination and was set by the level
and variability in the analytical batch blanks, rather than instrumental
sensitivity. These phthalates were detectable at lower levels but their
measurement was not reliable below the reporting limit once the
uncertainty in the blank subtraction was taken into account.
Each analytical batch contained at least 5 method blanks, consisting of
the entire analytical procedure but omitting the sample. Each sample was
extracted and analysed in duplicate and every sample was also spiked with
DBP, BBP, DEHP and DIDP for a recovery check. As there are no reference
materials with certified values for phthalates in infant formulae, and no
other suitable infant formulae reference materials were available, the
accuracy of the analysis was ensured by this spiking and recovery check
procedure. The following criteria were obligatory for the acceptance of
analytical results:
- the response of the quantification and qualification ions should
maximise within plus or minus 5 seconds compared with the retention time
of the authentic standards;
- the recovery of the spiked samples should lie in the range 70-120
per cent;
- the ratio of the quantification ion versus the qualification ion for
samples should be no greater than 2 standard deviations from the mean of
the ratio for the spiked samples run in that batch.
All results were corrected for recovery.
The main sources of uncertainty in the analysis were (a) the variability
in the batch blank which was used to correct all values and (b) any
variability in the analytical recovery. The first source is most important
as the measured value approaches the reporting limit but becomes less
important and finally negligible as the measured value rises. The second
source of uncertainty is more constant and can be assessed from the
agreement between the duplicates and by the within-batch agreement between
the spiked samples. Thus, the uncertainty of the analysis depends on the
measured value. Indicative estimates of uncertainty are about plus or
minus 10 per cent for the reported BBP and total phthalate levels,
measured as DMP, and about plus or minus 15 per cent for DEHP levels.
Results
Phthalate concentrations were reported as purchased, i.e. on a
dry-weight basis for powders and as a liquid for the ready-to-feed
products. Table 2 summarises the
concentrations of individual and total phthalates (measured as DMP) in all
the infant formulae samples analysed, together with the levels found in
the 1996 survey for comparison. However, it should be noted that direct
comparison between the results of the two surveys is difficult. Samples
analysed in 1996 were composites containing more than one batch of a
product and in some cases more than one product.
Full details of the concentrations found in the individual retail
samples of infant formulae analysed during the 1998 survey and full brand
information are given in Table 3. The absence
of a particular product means only that the product was not included in
the survey. No further meaning should be read into the absence of that
product from this information sheet.
Twelve of the 39 samples analysed did not contain any of the 7
individual phthalates analysed at concentrations above the appropriate
reporting limits. Only 3 of the 7 individual phthalates analysed (DBP,
BBP, DEHP) were present at concentrations above the appropriate reporting
limits in the remaining 27 samples. Although not specifically targeted for
analysis, there was no evidence of significant dicyclohexyl phthalate,
dioctyl phthalate nor di-isononyl phthalate at the LC-MS retention times
expected.
DEHP was the most abundant individual phthalate and was measured in 22
of the 35 powder samples at concentrations ranging from 0.05-0.44 mg/kg;
the remaining powder samples contained less than 0.05 mg/kg. DEHP was also
measurable in 1 of the 4 ready-to-feed liquid samples at a concentration
of 0.015 mg/kg, with the other 3 ready-to-feed samples containing less
than 0.005 mg/kg.
Total phthalates, measured as DMP, were present in 34 of the 35 powder
samples at concentrations ranging from 0.1-0.6 mg/kg, with the remaining
sample containing less than 0.1 mg/kg. Total phthalates were measurable in
1 of the 4 ready-to-feed samples at a concentration of 0.07 mg/kg, with
the other liquid samples containing less than 0.05 mg/kg.
A limited comparison of the results for the 1996 and 1998 survey
indicates that, for those products analysed in both 1996 and 1998 where
individual and/or total phthalates were present at concentrations at or
above the reporting limits used for the 1998 survey, the range of
phthalate concentrations in the individual 1998 retail samples were
typically lower or equal to the level observed in the relevant composite
sample in 1996.
Dietary exposure to individual and total phthalates at birth (bodyweight
about 2.5-3.5 kg) and 6 months (bodyweight about 7.5 kg or more) were
estimated using the average phthalate concentration in each product
determined during this survey and the appropriate manufacturers' feeding
guides on the packaging of the product. For each phthalate present at less
than the reporting limit, it was assumed that the concentration of that
phthalate was equal to its reporting limit. It was also assumed that
infant formulae were the only source of nutrition. When expressed on a
bodyweight basis, consumption of infant formulae, and thus estimated
exposure to phthalates, are higher in new-born infants than in older
children.
For each compound, there will be a range of daily exposures between
birth and 6 months due to changes in feeding regime and bodyweight over
this period in an infant's life. These estimated exposure ranges are given
in Table 2 and compared with the
exposures estimated from the results of the previous survey of infant
formulae in 1996.
Interpretation
The concentrations of individual phthalates measured in the current
survey were about half those reported in the 1996 survey. The total
phthalate levels found in the current survey (less than 0.1-0.6 mg/kg) are
some 12-17 times lower than those reported in 1996, when the
concentrations of total phthalates were between 1.2-10.2 mg/kg. The
current results for total phthalates (measured as DMP) are also similar to
those found in a Dutch ring trial for the analysis of phthalates. In this
trial, organised by the Utrecht Inspectorate for Health Protection in
1997, infant formulae samples were analysed by participating laboratories
using analytical methods of their own choice. The results obtained in the
trial by all participants, which included CSL Food Science Laboratory,
agreed closely.
The reasons for the lower concentrations found in this 1998 survey are
not clear. The difference between the two data sets is unlikely to be due
to the analysis itself. Quality control systems are in place at CSL Food
Science Laboratory, Norwich to ensure that all results, including those
reported in 1996, are reliable and reproducible. Improvements have been
made to the analytical methodology since the 1996 survey was reported but
those results have been confirmed by reanalysis of the 1996 samples using
both the original methodology and the improved method used for the 1998
survey.
Following publication of the 1996 survey results, manufacturers of
infant formulae were asked to trace the sources of phthalates present in
infant formulae so that the levels may be reduced. Awareness of the
potential for phthalate contamination of infant formulae has generally
increased following publication of the 1996 survey. The increased efforts
by manufacturers and suppliers of ingredients to trace potential sources
of phthalate contamination of infant formulae and/or minor changes in the
source or supply of ingredients, may have had an effect.
Statistical analysis of the data set indicates that, for the samples
included in this 1998 survey, there were no significant differences in the
concentrations of individual or total phthalates between milk-based and
soya-based formulae. For the samples included in this survey, there were
also no overall significant differences in the concentrations of
individual or total phthalates between casein-dominant and whey-dominant
milk-based formulae. Total phthalate concentrations varied with packaging
type. The reasons for this are not clear and it may be due to reasons
other than the packaging used. The packaging was not analysed for
phthalates as part of this survey. Variation in the concentrations of some
individual phthalates was also observed. However, estimated dietary
exposure to individual phthalates were below relevant TDIs for all
products and parents are not advised to change the feeding regimes of
their infants, or to switch brands, on the basis of these results.
The SCF has considered the toxicity of phthalates and has established
TDIs, or temporary TDIs, for several of the chemicals in the group (see
Table 2). The concentrations of
phthalates measured in the most recent survey are considerably lower than
those reported in 1996. The consequent estimated intakes are well below
the respective TDIs for individual phthalates, where these have been set.
The concentrations of phthalates found in the 1996 survey of infant
formulae were considered unlikely to pose any health risks to infants. The
increased margins of safety indicated by the current results are
reassuring. Parents are not advised to change the feeding regimes of their
infants or to switch brands on the basis of these results.
Units
A kilogram (kg) is one thousand grams (g).
A milligram (mg) is one thousandth of a gram (g).
A microgram is one millionth of a gram (g).
References
- International Programme on Chemical Safety (1992)
Diethylhexyl phthalate. Environmental Health Criteria 131,
publ. World Health Organization, Geneva.
- MAFF (1996)
Phthalates in Food. Food Surveillance Information Sheet Number
82.
- Sharman, M., Read, W.A., Castle, L. and Gilbert, J.
(1994) Levels of di-(2-ethylhexyl)phthalate and total phthalate esters
in milk, cream, butter and cheese. Food Additives and Contaminants
11, 375-385.
- Castle, L., Gilbert, J. and Eklund, T. (1990)
Migration of plasticiser from poly(vinyl chloride) milk tubing. Food
Additives and Contaminants 7, 591-596.
- Cerbulis, J. and Byler, D.M. (1986) Isolation and
detection of dialkyl phthalates from pork. Journal Agricultural
and Food Chemistry 34, 198-200.
- Musial, C.J., Uthe, J.F., Sirota, G.R., Burns, B.G.,
Gilgan, M.W., Zitko, V. and Matheson, R.A. (1981) Di-n-hexyl phthalate
(DHP), a newly identified contaminant in Atlantic herring (Clupea
harengus harengus) and Atlantic mackerel (Scomber scombrus).
Canadian Journal of Fish and Aquatic Science 38,
856-859.
- Mayer, F.L., Jr., Stalling, D.L. and Johnson, J.L.
(1972) Phthalate esters as environmental contaminants. Nature
(London) 238, 411-413.
- MAFF (1995)
Phthalates in paper and board packaging. Food Surveillance
Information Sheet Number 60.
- Scientific Committee for Food (1996) Opinion on
phthalates in infant formulae (Expressed on 7 June 1996), Annex II to
Document III/5557/96, CS/PLEN/GEN/47-FINAL.
- MAFF (1996)
Phthalates in Infant Formulae. Food Surveillance Information Sheet
Number 83.
- CSL Report FD 98/34 (1998) 1998 Survey of infant
formulae for phthalates.
Further Information
Further information on this survey can be obtained from:
Dr Nigel Harrison,
MAFF, Joint Food Safety and Standards Group, Food Contaminants Division,
Room 234, Ergon House, c/o Nobel House,
17 Smith Square,
London SW1P 3JR
Tel: +44 (0)20 7238 6235
Fax: +44 (0)20 7238 5331
A copy of the full report of this survey has been placed in the MAFF
Library, Nobel House, London, SW1P 3JR Tel. No. + 44 (0)20 7238 6575. If
you wish to consult a copy please contact the library for an appointment
giving at least 24 hours notice or alternatively copies can be obtained
from the library: a charge will be made to cover photocopying and postage.
Table 3: Concentrations of individual and total phthalates in
individual retail samples of infant formulae
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Table 3
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Table 3 (If you have any other spreadsheet package)
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