3-Monochloropropane-1,2-Diol (3-MCPD) in Soy and Oyster
description
Transcript of 3-Monochloropropane-1,2-Diol (3-MCPD) in Soy and Oyster
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dient to soy sauces or the use of acid treatment in the
manufacturing of soy sauces possibly leads to the con-
3-MCPD was always higher than that of 1,3-DCP
(FSA, 2001).
3-MCPD was originally regarded by the European
Commissions Scientic Committee for Food (EC,1997) as a genotoxic carcinogen and the UK Food
.
* Corresponding author. Fax: +65 6324 4563.
E-mail address: [email protected] (K.O. Wong).
Food Control 17 (2006)0956-7135/$ - see front matter 2005 Elsevier Ltd. All rights reserved1. Introduction
3-Monochloropropane-1,2-diol (3-MCPD) is one of
the chloropropanol group of chemical contaminants
and is a well-known contaminant of acid-hydrolysed
vegetable protein (acid-HVP) (MAFF, 1999). In the tra-
ditional production of acid-HVP where defatted vegeta-
ble proteins are hydrolysed by hydrochloric acid,
3-MCPD is formed by high temperature chlorinationof residual lipids that are associated with the vegetable
proteins. The inclusion of acid-HVP as a savoury ingre-
tamination of the sauces with 3-MCPD. The contami-nant has been reported in sauces (Macarthur et al.,
2000; Nyman, Diachenko, & Perfetti, 2003) as well as
in many other foods and food ingredients such as
breads, cheeses, salami, burgers and modied starches
(Crews, Brereton, & Davies, 2001; Crews et al., 2002a;
Hamlet, 1998; Hamlet, Jayaratne, & Matthews, 2002).
1,3-Dichloropropan-2-ol (1,3-DCP), another chloropro-
panol, can be formed from 3-MCPD and has beenfound in soy sauce and related sauces. When 3-MCPD
and 1,3-DCP co-occurred in sauces, the level ofAbstract
A continuous national monitoring program is performed to monitor the levels of 3-monochloropropane-1,2-diol (3-MCPD) in
both soy and oyster sauces and to assess the dietary intake of 3-MCPD by the general Singapore consumers from sauces. The pro-
gram involved the requisition of laboratory reports on the 3-MCPD levels in the sauces from importers before importation as well as
sampling of sauces at the point of import and at domestic manufacturers for the analysis of 3-MCPD. Out of the 421 soy and oyster
sauce samples monitored between January 2000 and April 2002, 376 samples (89.3%) contained 3-MCPD levels at or below the
national maximum limit of 0.02 mg/kg. The upper bound average 3-MCPD concentration of all the sauces was 0.45 mg/kg. The
estimated average daily dietary intake of 3-MCPD from sauces based on the national maximum limit and based on the upper bound
average 3-MCPD level found in the monitoring program were calculated and compared with the Tolerable Daily Intake (TDI) of
2 lg/kg body weight. The average daily intake of 3-MCPD by Singapore consumers from sauces was below the TDI and this indi-cates that there is no health risk associated with the intake of 3-MCPD from sauces. However, consideration has to be taken into
account the total 3-MCPD intakes from all food sources in the diet.
2005 Elsevier Ltd. All rights reserved.
Keywords: 3-Monochloropropane-1,2-diol; Sauces; Dietary intake3-Monochloropropane-1,2-diosauces: Occurrence and
Kwok Onn Wong *, Yock H
Food Control Division, Food & Veterinary Administration, Agri-F
MND Complex, Sing
Received 23 May 2004; received in revised fdoi:10.1016/j.foodcont.2005.01.010(3-MCPD) in soy and oysteretary intake assessment
Cheong, Huay Leng Seah
Veterinary Authority, 5 Maxwell Road, #18-00, Tower Block,
e 069110, Singapore
9 January 2005; accepted 20 January 2005
www.elsevier.com/locate/foodcont
408413
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tially genotoxic in vivo and its level in food should also
be reduced to a level as low as technologically achievable
spectrometry (GC/MS) method previously validated by
an inter-laboratory collaboration trial (Brereton, Kelly,
Crews, Honour, & Wood, 2001). This method has been
accepted for Ocial First Action status by the Associa-
tion of Ocial Analytical Chemists (AOAC Ocial
Method 2000.01).Sauce samples that were collected at the point of im-
port and at the domestic sauce manufacturers were sent
to Setsco Services Pte Ltd, Singapore, for the analysis of
3-MCPD levels. Both the laboratory and the AOAC
Ocial Method 2000.01 that was employed by the lab-
oratory for determining 3-MCPD levels in sauces have
been accredited under the Singapore Accreditation
CouncilSingapore Laboratory Accreditation Scheme(SAC-SINGLAS). The laboratory has also routinely
Control 17 (2006) 408413 409(COC, 2001; COM, 2001).
In May 2001, the European Commissions ScienticCommittee for Food derived a Tolerable Daily Intake(TDI) of 2 lg/kg body weight for 3-MCPD (SCF,2001). The gure of 2 lg/kg body weight is the sameas the Provisional Maximum Tolerable Daily Intake
(PMTDI) established by the Joint Food and Agriculture
Organisation/World Health Organisation Expert Com-
mittee on Food Additives in June 2001 (JECFA,
2002). This study reports the results from the January
2000 to April 2002 period of an on-going monitoringprogram to monitor the 3-MPCD levels in soy and oys-
ter sauces. The results were used to evaluate whether the
level of 3-MCPD intakes from soy and oyster sauces is a
cause for health concern in Singapore by comparing the
estimated dietary intake of 3-MCPD with the TDI of
2 lg/kg body weight.
2. Materials and methods
2.1. Samples
A national monitoring program was instituted to
monitor the levels of 3-MCPD in both imported and
domestically manufactured soy and oyster sauces. The
program was conducted via requesting laboratory ana-lytical reports on the 3-MCPD levels in the sauces from
the importers before the products were imported. Sam-
pling of sauces at the point of import and at the domes-
tic sauce manufacturers for laboratory analysis of
3-MCPD was also conducted.
2.2. Determination of 3-MCPD levels
3-MCPD levels were all reported based on determina-Advisory Committee has recommended that 3-MCPD
should be reduced in foods and food ingredients to the
minimum detectable using an analytical method capable
of detecting levels down to 0.01 mg/kg (FAC, 1999). The
UKs Committee on Mutagenicity of Chemicals inFood, Consumer Products and the Environment(COM, 2000) and Committee on Carcinogenicity of
Chemicals in Food, Consumer Products and the Envi-
ronment (COC, 2000) have later reviewed new toxico-
logical data and concluded that 3-MCPD does not
have signicant genotoxic potential in vivo. However,
in view that 3-MCPD is still considered by COC as car-
cinogenic in animals (COC, 2000), the UKs Food Advi-sory Committee has advised the industry to reduce3-MCPD levels in all foods and food ingredients to
the lowest technologically possible (FAC, 2000). The
UKs COC and COM have regarded 1,3-DCP as poten-
K.O. Wong et al. / Foodtions made according to a gas chromatography/massparticipated in prociency testing program on the anal-
ysis of 3-MCPD in sauces run by the UK Central
Science Laboratory under the Food Analysis Perfor-
mance Assessment Scheme (FAPAS) and the labora-
tory has been obtaining satisfactory results.
Deuterated 3-MCPD (d5-3-MCPD) as an internal
standard was added to a known amount of sample fol-lowed by saline solution to extract 3-MCPD and the
mixture was blended to a homogenous consistency.
After sonication or centrifugation, diatomaceous earth
(Celite 545) was added to the 3-MCPD extract and
mixed thoroughly. The mixture was transferred to a
manually compacted glass chromatography column
and non-polar compounds were eluted using a mixture
of hexane and diethyl ether. 3-MCPD was eluted usingdiethyl ether and the 3-MCPD extract was concentrated
to a small volume on a water bath at 5070 C. A vol-ume of the concentrated extract was subsequently deri-
vatised using N-heptauorobutyrylimidazole (HFBI).
The derivatised sample was analysed by GC/MS using
the conditions summarised in Table 1.
Identication of 3-MCPD was based on the compar-
ison of the full scan mass spectrum of the samplechromatographic peak with a mass spectrum of HFBI-
derivatised 3-MCPD. Quantication was based on
Table 1
Conditions and instrument settings for determination of 3-MCPD by
GC/MS
Gas chromatograph Agilent GCMSD
Column DB-5MS (30 m 0.25 mm 0.25 lm)Injector temperature 270 COven temperature 50 C for 1 min, 2 C/min to 90 C,
40 C/min to 270 C, 270 C for 10 minCarrier gas Helium
Flow rate 1 mL/min
Injection method Split 20:1
Injection volume 1 lL
Mass spectrometer Agilent
Interface temperature 250 CSan range m/z 50500
Monitoring ion d5-3-MCPDm/z 257, 4563-MCPDm/z 291, 289, 275, 253, 453
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sauces and 17 oyster sauces. As these products do not
Concomparison of chromatographic peak areas for
3-MCPD at m/z 253 and for d5-3-MCPD at m/z 257.
The reporting limit was 0.010 mg/kg. The lowest calibra-
tion point was set at 0.005 mg/kg, at this point of detec-
tion the S/N ratio was above 3.
For quality assurance purposes, samples were ana-lysed in batches comprising: 10 samples; a reagent
blank; a sample spiked at 0.010 mg/kg. Quality criteria
were set such that: reagent blanks should not show a
3-MCPD response greater than that equivalent
to 0.006 mg/kg in a 8 g sample; and the recovery of
3-MCPD added to a sample in each batch at
0.010 mg/kg should fall within the range 80120%. The
results of recovery experiments that were routinelycarried out on each batch of samples always fell within
the acceptable range of 80120% and the data were
not corrected for recovery. The measurement uncer-
tainty was assessed as 0.0065 mg/kg at 0.01654 mg/kg
3-MCPD. The measurement uncertainty was taken into
account only when a product was assessed for regula-
tory compliance with the national maximum limit for
3-MCPD. Since the 3-MCPD levels were used toestimate the dietary intake of the contaminant, the data
presented in this paper did not take the measurement
uncertainty into consideration.
2.3. Food consumption data
The food consumption data was obtained from the
National Nutrition Survey 1998 conducted by theSingapore Ministry of Health (MOH, 2001). Dietary
practices, food frequency, and 24-h food intake ques-
tionnaires were used in the survey. Approximately
2400 individuals aged between 18 and 69 years partici-
pated in the survey to provide information on their
dietary patterns and food intakes. The average amounts
of soy and oyster sauces consumed per day (g/day) by
the average respondents, average consumers and highconsumers (dened as the 95th percentile) were obtained
based on the food consumption data. The amount of soy
and oyster sauces consumed was contributed by both
domestic and non-domestic uses and included those that
were consumed as table top sauces as well as those that
were used as ingredients in the preparation of dishes.
2.4. Estimation of dietary intake
The average dietary intake of 3-MCPD from soy and
oyster sauces was estimated for the average respondents,
average consumers and high consumers by multiplying
the average 3-MCPD level by the average amount of
sauces consumed per day by each of the corresponding
population group. The analytical 3-MCPD concentra-
tions in the sauce samples were used to calculate theaverage contaminant level. For samples with 3-MCPD
410 K.O. Wong et al. / Foodlevels below the reporting limit, the reporting limit ofcontain added HVP, the most likely source of contami-
nation of these samples could be the use of acid hydro-
lysed soy bean and/or wheat ingredients.
Three of the 58 domestically manufactured sauces
(5.2%) and 42 of the 363 imported sauces (11.6%) con-
tained 3-MCPD above the national maximum limit of
0.02 mg/kg. A considerable number of samples, 25 outof the 45 samples (55.6%) that contained 3-MCPD0.010 mg/kg was used in the calculation. The estimates
of 3-MCPD intakes were thus based on the upper bound
average level of contamination in sauces and were there-
fore an overestimate of the true intakes. The calculated
average daily intake of 3-MCPD per unit body weight
was then compared with the TDI/PMTDI of 2 lg/kgbody weight established by SFC/JECFA.
3. Results and discussion
3.1. Occurrence of 3-MCPD in sauces
Following the conclusion that 3-MCPD is non-genotoxic (COC, 2000; COM, 2000) and the establish-
ment of a TDI for 3-MCPD (SCF, 2001), the Australia
New Zealand Food Standards Council (FSANZ, 2002)
and the European Commission (EC, 2001) have adopted
a regulatory limit for the contaminant based on a 40%
dry matter content, which came into force in November
2001 and April 2002, respectively. The requirement of
normalization of dry matter content is due to the vari-ability in the dry matter content of the sauces. Surveys
on 3-MCPD levels in sauces that were conducted before
the European Commission or Australia/New Zealand
limits came into force in which the results were not nor-
malized for dry matter have previously been published
(FSANZ, 2003; Macarthur et al., 2000; Nyman et al.,
2003). As the majority of sauces in this monitoring pro-
gram were sampled before the above regulatory limitswere implemented, the dry matter contents of the sauces
were not determined and the 3-MCPD levels were also
not normalized for dry matter content. In this paper,
comparison of the 3-MCPD levels can only be made
based on the wet weight of the samples.
Table 2 summarises the levels of 3-MCPD found in
421 samples of soy and oyster sauce. Only three domes-
tically manufactured sauces (one sample of soy sauceand two samples of oyster sauce) have declared the pres-
ence of HVP, two (one sample each of soy sauce and
oyster sauce) of which did not have quantiable levels
of 3-MCPD. This suggested that 3-MCPD was either
absent or present in very low amounts in the HVP used
in these two sauces. Of the remaining 418 sauces that did
not declare the presence of HVP, 61 sauces (14.6%) have
3-MCPD levels above 0.01 mg/kg. These included 44 soy
trol 17 (2006) 408413above the national maximum limit, have 3-MCPD levels
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Table 2
Range of 3-MCPD levels in soy and oyster sauces
Product type Exporting/
producing
country
Number of
samples
without
declaration
of HVP
Number of
samples
with
declaration
of HVP
Number of samples in each range (mg/kg) of 3-MCPD Upper
bound
average
(mg/kg)
60.01a >0.010.02 >0.020.05 >0.050.2 >0.20.5 >0.53.0 >3.0
Soy sauce Australia 1 1
China 40 29 5 5 1 0.026
Hong Kong 13 11 2 0.012
Indonesia 4 3 1 0.133
Japan 28 23 5 0.017
Malaysia 162 151 4 2 5 0.026
Philippines 1 1
Singapore 1 1
Singapore 42 37 4 1 0.011
Taiwan 13 6 1 4 2 0.481
Thailand 10 8 2 17.01
USA 2 2
K.O. Wong et al. / Food Control 17 (2006) 408413 411Oyster sauce Australia 2 2
China 6 3
Hong Kong 10 9
Japan 4 4
Malaysia 58 50 1
Singapore 2 1
Singapore 13 10 2
Taiwan 3 2
Thailand 6 5
a 0.01 mg/kg is the reporting limit for 3-MCPD.falling between >0.02 and 0.05 mg/kg. The upper bound
average 3-MCPD concentration for all the soy and
oyster sauces was 0.45 mg/kg. The highest 3-MCPD
level of 110.8 mg/kg was found in an imported soy
sauce; the highest 3-MCPD level found in soy sauces
in surveys conducted in UK, Australia and USA was
respectively, 30.5 mg/kg, 150 mg/kg and 876 mg/kg (all
published levels were based on wet weight of thesamples) (FSANZ, 2003; Macarthur et al., 2000; Nyman
et al., 2003).
Table 3
Estimated dietary intake of 3-MCPD from soy and oyster sauces
Population group Intake of
sauce (g/day)
Level of 3-MC
0.02 mg/kg
Dietary intake
(mg/kg body w
Average respondents (1869 years) 0.43 0.14
Average consumers (1869 years) 8.90 2.97
High consumers (1869 years) 19.80 6.59
Average consumers (18 to
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vey on the 3-MCPD levels in savoury foods in Singa-
The diligent eorts of all the ocers in the Food
Control Division who were involved in the national
Control 17 (2006) 408413respondents who have actually consumed soy and/or
oyster sauces.
3-MCPD levels of 0.02 mg/kg and 0.45 mg/kg were
used in the estimation of dietary intake of 3-MCPD
from soy and oyster sauces. The former level is the
national maximum limit for 3-MCPD in sauces. The lat-ter level is the upper bound average 3-MCPD level from
the monitoring program and it was used in the dietary
intake assessment assuming that products with 3-MCPD
levels above the national maximum limit were available
in the market and have been consumed.
The dietary intakes of 3-MCPD by average respon-
dents, and by average consumers from various
age groups were considerably below the TDI at both3-MCPD levels of 0.02 mg/kg and 0.45 mg/kg (Table
3). For high consumers of any age group, dietary intakes
were
-
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3-Monochloropropane-1,2-diol (3-MCPD) in soy and oyster sauces: Occurrence and dietary intake assessmentIntroductionMaterials and methodsSamplesDetermination of 3-MCPD levelsFood consumption dataEstimation of dietary intake
Results and discussionOccurrence of 3-MCPD in saucesEstimation of dietary intake
AcknowledgmentsReferences