INTERNATIONAL PROGRAMME ON CHEMICAL SAFETY
WORLD HEALTH ORGANIZATION
SAFETY EVALUATION OF CERTAIN
FOOD ADDITIVES
WHO FOOD ADDITIVES SERIES: 42
Prepared by the Fifty-first meeting of the Joint FAO/WHO
Expert Committee on Food Additives (JECFA)
World Health Organization, Geneva, 1999
IPCS - International Programme on Chemical Safety
EVALUATION OF NATIONAL ASSESSMENTS OF INTAKE OF tert-BUTYLHYDROQUINONE
(TBHQ)
First draft prepared by
Junshi Chen
Chinese Academy of Preventive Medicine, Beijing, China
1. INTRODUCTION
The Committee assessed the intake of tert-butylhydroquinone
(TBHQ), for which maximum limits have been proposed in a wide range of
food products in the draft General Standard for Food Additives (GSFA)
being developed by the Codex Committee on Food Additives and
Contaminants (CCFAC). The highest level of use of TBHQ permitted in
the GSFA is 1000 mg/kg for frozen fish, fish fillet, and fish products
(category 9.2.1). TBHQ was evaluated previously by the Committee at
its nineteenth, twenty-first, thirtieth, thirty-seventh, and
forty-ninth meetings (Annex 1, references 38, 44, 73, 94, and 131). An
ADI of 0-0.7 mg/kg bw was allocated to TBHQ at the forty-ninth
meeting.
TBHQ is generally used as an antioxidant in animal-derived food
products and in fats or oils. It is often used in conjunction with
butylated hydroxyanisole, butylated hydroxytoluene, and propyl gallate
to provide a synergistic antioxidant effect.
Information was provided by six countries: Australia, Brazil,
China, New Zealand, the United Kingdom, and the United States. A
combined assessment was provided by Australia and New Zealand
(Aus-NZ). The submitted estimates were based on data on poundage,
household surveys, model diets, and individual dietary records. A
summary of the types of data submitted is shown in Table 1.
2. SCREENING OF tert-BUTYLHYDROQUINONE BY THE BUDGET METHOD
Three countries submitted information derived by the budget
method, based on the use of TBHQ only in solid food and not in
beverages. Screening of food additives by this method at CCFAC
identified TBHQ as an additive for which a detailed intake assessment
was required. The theoretical maximum level of use for TBHQ in solid
food was less than the national maximum permitted level of use in all
three countries and was also less than the highest level in the
proposed draft GSFA (1000 mg/kg; Table 2). A detailed assessment of
intake of TBHQ in solid food is therefore required.
3. ASSESSMENTS OF INTAKE OF tert-BUTYLHYDROQUINONE
3.1 Assessment based on data on poundage (disappearance)
Estimates of the amount of TBHQ available per capita based on
poundage data are given in Table 3 for two countries and compared with
the ADI. The estimates are both lower than the ADI, at 0.004 mg/kg bw
Table 1. Summary of submissions on tert-butylhydroquinone
Country Budget Poundage FBS/HES/ Model Individual dietary
method data sales data diets records
Aus-NZ x x x
Brazil x x
China x x x
United Kingdom x
United States x x
FBS, food balance sheet; HES, household economic survey; sales, retail stores
Table 2. Estimate of a theoretical maximum level for
tert-butylhydroquinone (TBHQ) from the budget method
Country % food or National GSFA Theoretical
beverage supply maximum maximum maximum
containing TBHQ level (mg/kg) levela (mg/kg) level (mg/kg)
Aus-NZ 50% solid foods 200 1000 solid foods 56
Brazil 25% solid foods 200 1000 solid foods 110
China 15% solid foods 200 1000 solid foods 190
GSFA, General Standard for Food Additives; Aus-NZ, Australia-New Zealand
a GSFA proposes maximum use levels of 1000 mg/kg for 9.2.1, 'Frozen fish, fish
fillets, and fish products, including molluscs, crustacea, and echinoderms';
200 mg/kg for 14.1.4, 'Water-based flavoured drinks'.
per day (1% of the ADI) in China and 0.14 mg/kg bw per day (20% of the
ADI) for high consumers in the United States.
3.2 Assessment based on data from household surveys
Only one country submitted data based on a household survey. The
estimates of intake of TBHQ from Brazil from two data sources (AC
Nielsan Brazil sales data for 1992-96 and Datamark data, mainly from
manufacturers, for 1984-94) indicate that potential intake is lower
than the ADI: 0.08-0.13 mg/kg bw per day, or 10-20% of the ADI. The
estimates were based on an assumption of a population of 159.75
million and maximum national use levels for all foods except chewing
Table 3. Estimates of intake of tert-butylhydroquinone (TBHQ) based on poundage data
Country Date Assumptions Estimated intake of % ADIa
BHT (mg/kg bw per day)
China ? Population, 0.004 1
1200 million 70% of total population
Used only in
solid foods
United Statesb 1987 Population, 0.005 (mean) 1
240 million 0.01 (90th percentile) 1
1995 Population, 0.07 (mean) 10
260 million 0.14 (90th percentile) 20
a JECFA ADI, 0-0.7 mg/kg bw
b Used in solid food and beverage mixes; assuming that 100% of population are
consumers and that the 90th percentile intake is twice the mean
gum. Maximum use was assumed for coconut, even though the use level
was based on a 60% fat content, resulting in an overestimate of TBHQ
intake.
3.3 Assessment based on model diets
Five countries submitted data based on model diets (Table 4). The
results are not strictly comparable, because different assumptions
were made. The model diets used in Aus-NZ and the United Kingdom were
constructed to estimate the intakes of a high consumer, assuming
maximum additive levels. The model used in the United States was
constructed to predict the TBHQ intakes of a long-term consumer by
using data on food consumption derived from food frequency data for
1982-88 from the Market Research Corporation of America and average
portion sizes from a three-day national food consumption survey
conducted in 1987-88 by the US Department of Agriculture. Maximum
additive levels were assumed.
The estimates for the intake of the mean consumer of TBHQ in
China and the United States are lower than the ADI, but those for high
consumers in Aus-NZ, China, and the United Kingdom all exceed the ADI.
When GSFA use levels were used, the resulting estimates far exceeded
the ADI.
Table 4. Model diets used to estimate intake of tert-butylhydroquinone (TBHQ)
Country Date Survey Assumptions Type of model TBHQ intake % ADI
(mg/kg bw
per day)
Aus-NZ 1983 National, 24-h recall; Two models: Aus-NZ/GSFA High consumerb
adults, 25-64 years; -- maximum levels (Aus-NZ or GSFA) Aus-NZ permissions 2.1 300
sample, 6254; -- 95th percentile high consumption level GSFA permissions 7.9 1100
body weight, 71 kg -- modified GSFA classification system
-- corrections for premixes and drink
bases
China 1992 National household One model Average consumer 0.69 100
survey, 24-h recall; 30 -- maximum GSFA levels High consumer 4.8 680
provinces; sample,
91 818; body weight,
60 kg
United Unit quantity diet One model: GSFA High consumerb 4.9 700
Kingdom -- unit quantity diet (Codex model with GSFA permissions
GSFA levels)
-- GSFA classification system
United 1982-88 14-day menu obtained Two models: US and GSFA Long-term consumer
States from MRCA food -- maximum additive levels (US or GSFA) US permissions, mean 0.37 50
frequency data (1982-87) -- 90th percentile high consumption level US permissions, 90th 0.74 100
combined with portion is twice mean consumption GSFA permissions, mean 0.62 90
sizes from USDA/NFCS -- all respondents are consumers GSFA permissions, 90th 1.2 180
(1987-88); > 2 years; -- GSFA classification system (except
body weight, 60 kg FSDU)
-- corrections for premixes and drink
bases
Table 4 (continued)
Aus-NZ, Australia-New Zealand; GSFA, General Standard for Food Additives; EU, European Union; MRCA, Market Research Corporation of
America; USDA/NFCS, US Department of Agriculture/National Food Consumption Survey; FSDU, foods for special dietary uses
a JECFA ADI, 0-0.7 mg/kg bw
b Assumed to consume one food with potentially highest TBHQ intake from two major food groups at the 97.5th percentile (United Kingdom) or
95th percentile (Aus-NZ) and from one food with potentially highest TBHQ intake from each of the other major food groups at a mean level
for all respondents
Data on high consumption of specific foods were provided by two
countries. High consumers of fats and oil or fat emulsions alone are
likely to exceed the ADI in the model used in Aus-NZ (4.8 mg/kg bw per
day, 280% of the ADI); however, when the GSFA level was used for
frozen fish, fish fillets, and fish products (category 9.2.1), the
estimated intake of high consumers was 600% of the ADI for Aus-NZ.
Furthermore, the estimated intake of TBHQ from soft drinks in Aus-NZ
was 340% of the ADI when the GSFA use level (200 mg/kg) was applied,
even though TBHQ is not currently permitted in soft drinks.
3.4 Assessment based on individual dietary records
Only Aus-NZ submitted data based on individual dietary records.
The estimate is based on a national survey of 6254 adults aged 25-64
conducted in 1983 from 24-h recall. The assumptions were: all
respondents were consumers, maximum Aus-NZ or GSFA additive levels, a
modified GSFA classification system, maximum additive levels within
any one group, correction for premixes and drink bases, and adjustment
of intakes for individual body weight. The TBHQ intake of mean
consumers was estimated to be 0.69 mg/kg bw per day for Aus-NZ levels
(100% of the ADI) and 1.2 mg/kg bw per day for GSFA levels (180% of
the ADI); the intakes for 95th percentile consumers were 2.1 (310%)
and 3.5 mg/kg bw per day (490%), respectively. The estimate for mean
consumers in Aus-NZ based on the national maximum use level is thus at
the ADI, but the estimates for high consumers (95th percentile) far
exceeded the ADI, particularly when GSFA use levels were used.
4. EVALUATION OF ESTIMATES OF INTAKE OF tert-BUTYL-HYDROQUINONE
The estimates of TBHQ intake based on poundage data (two
countries) and a household survey (one country) ranged from 0.004 to
0.14 mg/kg bw per day. The estimates for the mean consumer based on
model diets (five countries) and individual dietary records (two
countries) are at or below the ADI (50-100%), from 0.37 mg/kg bw per
day in the United States to 0.69 mg/kg bw per day in China and Aus-NZ.
The estimates for high consumers exceed the ADI, but the data
submitted are insufficient to estimate the number of such consumers or
the magnitude or duration of exposure to levels above the ADI.
The estimates of TBHQ intake based on GSFA use levels are
summarized in Table 5. Estimates derived from the additive levels and
range of uses in foods of the GSFA will result in grossly
overestimated intakes in any one country, because the GSFA is
generally compiled by adopting the highest level of use for any food
category submitted by countries and non-governmental organizations.
The range of use specified in the GSFA is also usually much wider than
in national standards. The estimates for mean consumers in Aus-NZ and
the United States were 180 and 90% of the ADI, respectively, but those
for high consumers were 490 and 180% of the ADI.
Table 5. Summary of estimates of intake of tert-butylhydroquinone (TBHQ) based on
additive levels permitted within the General Standard for Food Additives
Country Model Intake of TBHQ % ADIa
(mg/kg bw per day)
Aus-NZ Individual records, mean intake 1.2 180
(all respondents are consumers)
Individual records, 95th percentile 3.5 490
consumers
United States Model diet, mean intake 0.62 90
(all respondents are consumers)
Model diet, 90th percentile consumers 1.2 180
a JECFA ADI, 0-0.7 mg/kg bw
High consumers of single food groups, such as fats, oil and fat
emulsions, and frozen fish are likely to exceed the ADI of TBHQ,
particularly when GSFA use levels are used. According to the original
GSFA worksheets, the level of 1000 mg/kg for frozen fish, fish
fillets, and fish products was suggested by only one country and is
much higher than the use levels of other food categories (100-200
mg/kg). Furthermore, the number of countries that provided information
on the intake of TBHQ and the details provided is limited. This is the
main constraint to the validity of the evaluation from a global
perspective.
5. CONCLUSIONS AND RECOMMENDATIONS
5.1 National estimates of intake of tert-butylhydroquinone based on
maximum limits specified in the General Standard for Food
Additives
National estimates of intake of TBHQ based on maximum limits and
the range of foods specified in the GSFA were available for three
countries. The estimated mean intake was near or exceeded the ADI,
from 90% of the ADI in the United States to 180% of the ADI in Aus-NZ.
5.2 National estimates of intake of tert-butylhydroquinone based on
national or European Union maximum limits
All of the best estimates of national mean intake of TBHQ were at
or below the ADI of 0-0.7 mg/kg bw: 50% of the ADI for the United
States and 100% of the ADI for Aus-NZ and China, on the basis of data
from model diets or individual dietary records. The estimates for high
consumers based on additive levels in national standards exceeded the
ADI in some cases, e.g. 300% of the ADI for Aus-NZ; however, the data
submitted were insufficient to estimate the number of such consumers
or the magnitude or duration of intake of levels above the ADI.
All of the estimates were based on the assumption that TBHQ is
the only antioxidant in foods in which its use is permitted and that
all such foods contain the additive at maximum levels, thus tending to
overestimate actual intake. Actual intakes of TBHQ depend on the
relative proportions of butylated hydroxyanisole, butylated
hydroxytoluene, TBHQ, and other antioxidants used in foods, on
national levels of use according to good manufacturing practice, and
on the proportion of foods in any one category that contain the
additive.
5.3 Recommendations to the Codex Committee on Food Additives and
Contaminants
The Committee identified foods or food groups that potentially
contribute to high intake of TBHQ. On the basis of the assessment, the
Codex Committee may wish to review the appropriate levels in the GSFA
for: category 2, 'fats and oils/fat emulsions', category 9.2, 'frozen
fish, fish fillet and fish products, including molluscs, crustacea and
echinoderms', and category 14.1.4.1, 'soft drinks'.
The Committee noted that all of the estimates based on national
maximum use levels for TBHQ were lower than the ADI, but estimates
based on maximum limits and the range of foods specified in the GSFA
exceeded the ADI. The differences arise because the range of foods
specified in the GSFA is wider than in national authorizations and the
proposed levels of use in specific food categories are generally
higher than the national maximum levels.
6. BIBLIOGRAPHY
Australia New Zealand Food Authority (1997) Aus-NZ Food Standards
Code, Canberra.
Baines, J. Data sheets for Australia for TBHQ, BHA, BHT, sulfites, and
benzoates. Personal communication. Australia-New Zealand Food
Authority, Canberra, to J. Paakkanen, FAO, 5 January 1998.
Chen Junshi. Food additive intake from China. Personal communication.
Chinese Academy of Preventive Medicine, Beijing, to J. Paakkanen, FAO,
16 March 1998.
Codex Committee on Food Additives and Contaminants (1997) Report of
the Twenty-ninth Session of the Codex Committee on Food Additives
and Contaminants, Rome, Food and Agriculture Organization of the
United Nations (document ALINORM 97/12A, Appendix V).
Codex Committee on Food Additives and Contaminants (1998)
Consideration of the Codex General Standard for Food Additives:
Proposed draft revised annex A at step 3. Request for comments and
information. Rome, Food and Agriculture Organization of the United
Nations (document CX/FAC 98/9).
European Commission (1995) European Union Directive 95/2/CE, Brussels.
Fisher, C.E. Dietary exposure in the United Kingdom to the five
additives referred to JECFA by CCFAC. Personal communication. Joint
Food Safety and Standards Group, London, to J. Paakkanen, FAO, 29
April 1998.
Rulis, A.M. United States intake data on BHA, BHT, TBHQ, sulfites, and
benzoates. Personal communication. Food and Drug Administration,
Washington DC, to J. Paakkanen, FAO, 24 February 1998.
Toledo, M.C.F. Brazilian intake estimates of BHA, BHT, and TBHQ.
Personal communication. University of Campinas, to J. Paakkanen, FAO,
26 February 1998.
United States Department of Agriculture (1996) Nationwide food
consumption survey: 1989-91. Technical Information Service,
Springfield, VA, United States.