Number 181 June 1999
MAFF UK - SURVEY OF 3-MONOCHLOROPROPANE-1,2-DIOL (3-MCPD) IN ACID
HYDROLYSED VEGETABLE PROTEIN
Index to MAFF UK Food Surveillance Information
Sheets, 1999
See also:
187: MAFF, UK - Survey of 3-monochloropropane-1,2-diol
(3-MCPD) in soy sauce and similar products
Summary
A survey of 3-monochloropropane-1,2-diol (3-MCPD) in acid-hydrolysed
vegetable protein (acid-HVP) available in the UK has been completed.
Fifty samples of acid-HVP, a commonly used savoury food ingredient,
were obtained at the end of 1998 and analysed using a validated
method of analysis with a detection limit of 0.01 mg/kg. The objective
was to assess the progress made by manufacturers in complying with
advice given by the Food Advisory Committee (FAC) in October 1996
that industry should take all steps necessary to ensure that 3-MCPD
cannot be found in any foods or ingredients, when using a validated
method of analysis capable of measuring down to 0.01 mg/kg.
3-MCPD was undetectable in 21 samples (42 per cent) analysed in
the survey, with a further 9 samples (18 per cent) containing between
0.01 and 0.02 mg/kg. 3-MCPD was found to be present in 8 samples
(16 per cent) at between 0.02 and 0.05 mg/kg; in 3 samples (6 per
cent) at between 0.05 and 0.1 mg/kg; and above 0.1 mg/kg in nine
samples (18 per cent). The highest result was 2 mg/kg. Although
overall the survey shows that levels of 3-MCPD in acid-HVP have
continued to decline since earlier MAFF surveys were carried out
in 1990 and 1992, the results for a number of products are high
relative to the limit recommended by the FAC. In approximately half
of these cases, the sample details provided indicated that these
samples were manufactured prior to or early in 1998. A possible
reason for some of the elevated levels therefore is that the industry
had not at that time completed its efforts to reduce 3-MCPD to below
the 0.01 mg/kg level.
The FAC considered the results of this survey at its meeting on
6 May 1999. The Committee noted the efforts made by acid-HVP manufacturers
who, in line with FAC advice, had markedly reduced the levels of
3-MCPD in their products compared with those found in earlier MAFF
surveys. However, it stressed the need for continued vigilance by
the industry to ensure that these low levels are consistently achieved.
It noted that the use of a validated method, which is now available,
for measuring 3-MCPD in food down to a level of 0.01 mg/kg would
assist in this task.
Background
HVP is a food ingredient prepared by the acid or enzymatic hydrolysis
of vegetable protein. It is used to flavour a variety of savoury
foods, including many processed and pre-prepared foods, soups, gravy
mixes, savoury snacks and bouillon cubes, with the typical levels
of use ranging from 0.1 per cent to approximately 0.8 per cent in
these foodstuffs.
In the 1980s it was found that the procedure used to manufacture
acid-HVP, the most widely used type of HVP, could generate small
amounts of contaminants known as chloropropanols, the most common
of which is 3-MCPD. Conventional acid-HVP is produced using strong
hydrochloric acid and chloropropanols are formed as a result of
the high temperature chlorination of glycerol present in fats and
oils in the crude protein starting materials.
Based on available toxicity data and information on the technology
of acid-HVP production, in 1990 the European Commission's Scientific
Committee for Food (SCF) recommended that levels of 3-MCPD in HVP
should not exceed 10 mg/kg. MAFF conducted surveys of the levels
of 3-MCPD in acid-HVP in 1990 and again in 1992 which showed a decline
in levels of this chloropropanol. Of the 39 samples tested in the
1990 survey, 33 exceeded the then limit of detection for 3-MCPD
of 1 mg/kg, with 23 of these being above the SCF's recommended limit
of 10 mg/kg.1 In 1992, half of the
34 acid-HVP samples included in the survey contained 3-MCPD in excess
of 1 mg/kg.2
In 1994, following a review of the available data, the SCF advised3
that "residues of 3-MCPD in food products should be undetectable
by the most sensitive analytical method" and "that all
efforts should be undertaken to develop methods leading to products
not containing chlorinated propanols". As a consequence, manufacturers
investigated ways of changing their production processes to further
reduce or to eliminate 3-MCPD in their products.
The FAC considered the SCF's advice in May 1996. At that time the
only known dietary source of 3-MCPD was acid-HVP. The Committee
noted that the intakes of 3-MCPD by consumers were likely to be
very low. As a precautionary measure, the Committee recommended4
that "3-MCPD should be reduced to the minimum detectable by
the most sensitive and reliable analytical method available".
However, since HVP manufacturers stated that they were unable to
remove 3-MCPD entirely from their products, it further recommended
that "the food industry should be consulted on the timescale
over which a switch could be made from acid-HVP to other products
which do not contain 3-MCPD".
In October 1996 the FAC considered the issue again. The Committee
was informed that the major UK manufacturer could now produce acid-HVP
with undetectable levels of 3-MCPD, when analysed using a method
capable of detecting levels down to 0.01 mg/kg, the lowest level
which could be reliably measured. As a result of these analytical
and technological improvements, 3-MCPD had been effectively eliminated
from its HVP products. The Committee also learned that 3-MCPD might
occur at low levels in several other foods and food ingredients
as a result of processing or storage conditions. On the basis of
this new information, and in line with the SCF's advice, the FAC
recommended5 that "within 18
months, industry should take all the steps necessary to ensure that
3-MCPD cannot be found in any foods or ingredients, regardless of
the method of manufacture, when using a validated method of analysis
capable of measuring down to 0.01 mg/kg, the lowest level of detection
currently achievable". This meant that the use of acid-HVP
could continue provided that it met the 0.01 mg/kg limit.
In April 1998, the FAC confirmed its advice that industry should
reduce levels of 3-MCPD in foods and food ingredients to less than
0.01 mg/kg.6 Most manufacturers of
acid-HVP stated that they were making good progress and could either
supply acid-HVP which complied with the FAC's advice or would shortly
be able to do so.
Following the FAC's April 1998 meeting, the Joint Food Safety and
Standards Group (JFSSG) commissioned a survey to determine the levels
of 3-MCPD in acid-HVP then available in the UK. The work was carried
out to assess the progress which had been made by the industry in
complying with the FAC's advice.
Methodology
The survey
Samples were obtained between November and December 1998. The fifty
samples selected for the survey were all received from UK food or
flavouring companies rather than from HVP manufacturers in order
to represent products in actual use at that time. JFSSG wrote to
the companies in August 1998 asking them in the first instance to
provide a list of the acid-HVP products which they were currently
using in their foods and of which they might be able to provide
samples from a recent batch. For each sample of acid-HVP, full details
were requested of the product name, the manufacturer, whether the
product was a powder, paste or liquid and, if available, the annual
usage in kilograms of the product by the company and the range of
foods in which the acid-HVP was used. From this information, the
samples were selected primarily on the basis of perceived market
share, from seven different manufacturers which supply the UK market.
JFSSG then wrote again to the food and flavouring companies in November
1998 with a request for specific samples.
Where the use of the same acid-HVP was reported by different companies,
no more than one sample of that product was included in the survey
in order to cover as many different products as possible. Where
a particular HVP was manufactured by more than one company, it was
aimed to take samples from as wide a range of potential sources
as possible. All of the samples were dry powders, with the exception
of a single liquid and a single paste.
The survey took account of the JFSSG guidelines for planning and
reporting surveys.7 In line with
these guidelines, brand names have not been provided since acid-HVP
is an intermediate product used in the manufacture of foodstuffs
and is not available to consumers at the wholesale or retail level.
Method of analysis
The sample analysis was carried out at the CSL Food Science Laboratory,
Norwich. Samples were analysed by a validated gas chromatographic-mass
spectrometric (GC-MS) method, using deuterated 3-MCPD as an internal
standard.8 To extract 3-MCPD, saline
solution was added and the mixture was blended to a homogeneous
consistency. After sonication, the contents of an ExtrelutTM
refill pack were added and mixed thoroughly. The sample plus ExtrelutTM
was transferred to a glass chromatography column and the non-polar
components eluted using a mixture of hexane and diethyl ether (90
+ 10). The 3-MCPD was eluted using diethyl ether and the sample
extract concentrated to a small volume. A portion of the concentrated
sample extract was then taken for derivatisation with heptafluorobutyrylimidazole
prior to injection onto the GC-MS. Quantification was based on comparison
of chromatographic peak areas for 3-MCPD at m/z 253 and for the
deuterated 3-MCPD at m/z 257.
Calibration standards over the range 0.006 to 0.250 mg/kg were
run with each batch of samples. The results for samples found to
contain over 0.2 mg/kg were confirmed by re-analysis using a reduced
sample size in order to bring the response well within the calibration
range. The limit of detection for this work was assessed as being
0.01 mg/kg.
For quality assurance purposes samples were analysed in batches
comprising: 5 samples; a reagent blank in which sodium chloride
was substituted for acid-HVP; a sample spiked at 0.010 mg/kg; and,
as a reference material, an acid-HVP sample previously characterised
by CSL and used as a collaborative trial test material. Quality
criteria were set such that: reagent blanks should not show a 3-MCPD
response equivalent to 0.005 mg/kg acid-HVP or more; the values
for the reference material should not fall outside the value determined
at the collaborative trial plus or minus the reproducibility limit
(i.e. 0.029 plus or minus 0.010 mg/kg); and the recovery of 3-MCPD
added to a single sample in each batch at 0.010 mg/kg should fall
within the limits determined during in-house testing (62 per cent
to 115 per cent) for acid-HVP containing 3-MCPD within the calibration
range.
The analytical data showed that the analyses met the quality criteria
set, with the exception of one batch which was re-analysed. The
mean value for the reference acid-HVP was 0.031 mg/kg with a standard
deviation (sd) of 0.005 (n=12) and all determinations of 3-MCPD
in the acid-HVP reference material fell within plus or minus the
reproducibility limit of the collaborative trial mean. Recoveries
typically ranged between 80 per cent and 100 per cent, although
values could not be assessed accurately in all cases either because
the pre-spiking 3-MCPD content of the samples was too low to be
quantified accurately or because the acid-HVP selected for spiking
contained high levels of 3-MCPD, precluding the accurate determination
of an additional 0.01 mg/kg. The significance of recovery, however,
was diminished by the use of the deuterated internal standard. As
long as a quantifiable level of 3-MCPD was extracted and survived
the clean-up and determination procedures any losses would be compensated
for by an equivalent loss of internal standard. For each of the
batches in this work sufficient deuterated 3-MCPD was detected to
ensure confidence in the reliability of the data produced.
Results
The results of the acid-HVP survey are provided in Table
1. (Table 2 lists the number of products
by manufacturer based on information provided by the food and flavouring
companies which supplied the samples.) All results are reported
on a dry weight basis, with the results for the liquid and paste
samples having been corrected by assuming dry solids contents of
40 per cent and 85 per cent respectively. The results show that
levels of 3-MCPD were below the FAC's recommended limit in 21 (42
per cent) of the survey samples. Levels were between 0.01 mg/kg
and 0.05 mg/kg in 17 samples (34 per cent), between 0.05 and 0.1
mg/kg in 3 samples (6 per cent) and above 0.1 mg/kg in 9 samples
(18 per cent). The highest result was 2 mg/kg.
Interpretation
Set against the results for surveys conducted in 1990 and 1992,
the present survey is encouraging and confirms the continuing progress
which has been made to reduce levels of 3-MCPD in acid-HVP in line
with the FAC's advice (Figure 1). A significant
number of the samples in this survey, nevertheless, have been found
to contain 3-MCPD at levels higher than that recommended by the
FAC. In 23 of these cases the date of manufacture reported by the
user was prior to or early in 1998 (Table 1).
For one sample the date of manufacture was attributed to 1996 and
in a further 11 samples to 1997. The elevated levels in these cases
may have arisen because some manufacturers had not by then completed
their efforts to reduce 3-MCPD levels to below 0.01 mg/kg and therefore
were not yet able to comply fully with the FAC's advice. However,
a few of the higher levels of 3-MCPD recorded in the survey were
attributed to batches manufactured in the latter part of 1998, suggesting
that continuing vigilance is needed to ensure that compliance with
the 0.01 mg/kg limit is achieved consistently.
The manufacturers of those samples supplied which yielded analytical
results in excess of 0.1 mg/kg were sent details of these analyses
and asked to comment on any reasons for the elevated levels observed.
A summary of the responses received is given in Annex
1.
Since HVP is generally used in foods at low levels of not more
than 1 per cent, the level of 3-MCPD in the final foodstuff is considerably
less than the level of the contaminant present in the HVP itself.
The continued reduction in levels of 3-MCPD in acid-HVP will further
lessen the amount entering the UK diet as a contaminant of HVP.
The FAC considered the results of this survey at its meeting on
6 May 1999. The Committee noted the efforts made by acid-HVP manufacturers
who, in line with FAC advice, had markedly reduced the levels of
3-MCPD in their products compared with those found in earlier MAFF
surveys in 1990 and 1992. However, it stressed the need for continued
vigilance by the industry to ensure that these low levels are consistently
achieved. It noted that the use of a validated method, which is
now available, for measuring 3-MCPD in food down to a level of 0.01
mg/kg would assist in this task.
References
- MAFF (1991) Survey of hydrolysed vegetable proteins
for chlorinated propanols. CSL Report FD 91/6.
- MAFF (1993) Survey of chlorinated propanols
in hydrolysed vegetable protein 1992. CSL Report FD 93/17.
- European Commission (1997) Opinion on 3-monochloropropanediol
(3-MCPD), expressed on 16 December 1994. pp. 31-33 in Reports
of the Scientific Committee for Food. Food Science and Techniques,
Thirty-sixth Series. Office for Official Publications of the European
Community, Luxembourg.
- Food Advisory Committee (1996) Press Release
6/96 Update on chloropropanols in hydrolysed vegetable protein.
- Food Advisory Committee (1996) Press Release
13/96 Update on chloropropanols in hydrolysed vegetable proteins.
- Food Advisory Committee (1998) Press Release
5/98 Update on 3-MCPD in food and food ingredients.
- JFSSG
(1998) Guidelines for Planning and Reporting JFSSG Surveys.
- Kelly, J., Crews, C. and Brereton, P. (1998)
Determination of 3-monochloropropane-1,2-diol in food and food
ingredients using mass spectrometric detection: collaborative
trial. CSL Report FD 97/75
Further Information
The full report of this survey is held in the MAFF Library, Nobel
House, 17 Smith Square, London, SW1P 3JR; Tel: +44 (0)171 238 6575.
If you would like to consult a copy, please contact the Library
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.
For further information please contact:
Dr A M Davies
MAFF, Joint Food Safety and Standards Group
Additives and Novel Foods Division
Room 232 Ergon House
c/o Nobel House
17 Smith Square
LONDON SW1P 3JR
Tel: +44 (0) 171-238-6217
Fax: +44 (0) 171-238-6263
e-mail a.davies@fsci.maff.gov.uk
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