Caballero B. (ed.) Encyclopaedia of Food Science, Food Technology and Nutrition. Ten-Volume Set

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0037 The food industry has become progressively more

vertically integrated, from production through

processing to retailing, by the development of multi-

national agribusiness and large chain food stores, that

increasingly order food directly from the producers.

This means that the buyers for these food chains

become exceedingly important arbiters of the national

diet in deciding the choice available to the consumer.

Emerging Issues

0038 The creation of the WTO and the increasing power of

large food corporations have highlighted several

issues of control over food, from consumer pressures

to national and international governance.

New Technologies

0039 Consumer and environmental lobby groups have put

a brake on the use of genetically modified (GM)

foods: they disrupted the WTO meeting in Seattle

in early 2000 by protests against the trade in GM

crops; they caused agribusiness to discontinue the

development of terminator genes to prevent plant

replication; and consumer pressure in developed

countries such as the UK has curtailed the sale of

GM products as well as the conduct of field trials.

0040 Resistance to the use of the new technology in

agriculture and food production is based on several

fears: the safety for consumption; the control over

world food supply of the large corporations that de-

velop the technology; the potential detrimental effects

on the environment from cross-pollination; and the

lack of benefits to developed country consumers as

opposed to the seed and pesticide manufacturers.

These arguments currently outweigh the arguments

for the potential benefits, within appropriate socio-

economic structures, to farmers and consumers in

other parts of the world by the development of

crops that are resistant to adverse climatic conditions

and pests and that have higher yields and content of

specific nutrients, factors that could expand the areas

of crop production, increase total food production,

and hence price in line with the expected population

growth, and improve nutritional value.

Governance

0041 Such consumer pressures have also led to other issues

of governance in relation to national and international

political bodies that control economics, including

food. For example, consumer and professional pres-

sures following a series of food safety scares in the UK

during the 1980s have led to the separation within

government of the structures that regulate the food

supply from those that regulate agriculture as there

are potentially conflicting interests between con-

sumer and producer. A Food Standards Agency was

established in 2000 to regulate food ‘from farm to

fork.’ The EU has subsequently proposed a similar

structure at European level. This brings to the fore the

tensions in governance between national and regional

control over food and the extent to which these are

dominated by WTO rules in the interests of free trade.

Similar issues arise in global governance, underlining

the need for new arrangements to make more effect-

ive the relationships between the UN, WTO, G7,

IMF, and other bodies.

Conclusion

0042Food and nutrition involve highly political issues that

determine both access to sufficient food and the com-

mercial and consumer pressures on a balanced diet.

See also: Community Nutrition; European Union:

European Food Law Harmonization; Malnutrition: The

Problem of Malnutrition; Malnutrition in Developed

Countries; Nutrition Policies in WHO European

Member States; Refugees; Scurvy; World Health

Organization

Further Reading

ACC/SCN (1997) Nutrition and Poverty. Nutrition Policy

Paper 16. Geneva: ACC/SCN.

ACC/SCN (2000) Fourth Report on the World Nutrition

Situation. Geneva: ACC/SCN.

Atkinson J (1996) Farmers, Food and the WTO. Oxfam

Policy Briefing Paper.

Berg A (1973) The Nutrition Factor. Its Role in National

Development. Washington, DC. The Brookings Institution.

British Nutrition Society (1991) Nutrition and Develop-

ment: symposium & workshop. Proceedings of the

Nutrition Society 51(1): 71–107.

Food Industry, Nutrition and Public Health (1997) Sympo-

sium. Proceedings of the Nutrition Society 56(3): 807–888.

George S (1984) Ill Fares the Land. Essays on Food, Hunger

and Power. London: Writers and Readers Publishing

Cooperative Society.

Jolly R and Cornia GA (eds) (1984) The Impact of World

Recession on Children. UNICEF Report. New York:

Pergamon Press.

Overseas Development Institute (2000) Reforming Food

Aid: Time to Grasp the Nettle? ODI Briefing Paper,

January. London: ODI.

Royal Society (1998) Genetically Modified Plants for Food

Use. London: Royal Society.

Sen A (1982) Poverty and Famines: an Essay on Entitlement

and Deprivation. Oxford: Oxford University Press.

Tansey G and Worsley T (1995) The Food System. A Guide.

London: Earthscan.

UN (1997) Renewing the United Nations: A Programme for

Reform. Report by the Secretary General. New York: UN.

World Health Organization (1988) Nutrition Policy

Experiences in Northern Europe. Report on a WHO

Consultation. Copenhagen: WHO EUP/ICP/NUT.

POLITICS AND NUTRITION 4615

POLYCYCLIC AROMATIC HYDROCARBONS

E Menichini and B Bocca, Istituto Superiore di

Sanita

, Rome, Italy

Introduction

0001 Polycyclic aromatic hydrocarbons (PAHs) are a large

class of organic compounds containing two or more

fused aromatic rings. In particular, the term PAHs

refers to compounds containing only carbon and

hydrogen atoms (i.e., unsubstituted parent PAHs

and their alkyl-substituted derivatives), whereas the

more general term ‘polycyclic aromatic compounds’

also includes the functional derivatives (e.g., nitro-

PAHs) and the heterocyclic analogs (e.g., aza-arenes).

The term ‘polynuclear’ is frequently used for ‘poly-

cyclic.’ Hundreds of PAHs may be formed. Over 100

PAHs have been identified in atmospheric particulate

matter and about 200 in tobacco smoke. PAHs have

very low water solubility, and are soluble in many

organic solvents and highly lipophilic.

0002 The nomenclature codified by the International

Union of Pure and Applied Chemistry (IUPAC) is

also used by the Chemical Abstract Service. Some

compounds, however, are commonly reported in

literature with nonsystematic names. Table 1 lists

the PAHs considered for this review. The selection is

based on their occurrence data (as being the most

frequently determined in environmental and food

analysis) and their toxicological concern. Benzo[a]-

pyrene (BaP) is the most widely studied compound

and most information on occurrence and toxicity of

PAHs is related to it. In the comparison of different

matrices, BaP has frequently been (and still is) used as

an indicator for the PAH class, as regards both the

levels of contamination and the carcinogenic risk.

Formation and Sources

0003PAHs are formed during incomplete combustion or

pyrolysis of organic material, such as coal, wood, oil

products, and garbage. Consequently, their formation

is typically associated to the processing of coal and

crude oil, power generation plants, incinerating

plants, various industrial processes, domestic and

residential heating (especially by wood and coal),

motor vehicle exhaust, fires (forest, agricultural,

cooking), and tobacco smoking. Volcanoes may rep-

resent a natural source with a locally relevant impact.

Because of these numerous and widespread sources,

PAHs are ubiquitous and occur in all environmental

tbl0001 Table 1 Frequently determined polycyclic aromatic hydrocarbons (PAHs) and their carcinogenicity

PA H

Abbrev.

Relative molecular mass IARC classification of carcinogenicity

Animal

Human

Phenanthrene PHE 178.2 I 3

Fluoranthene FA 202.3 I 3

Pyrene PY 202.3 I 3

Benz[a]anthracene BaA 228.3 S 2A

Chrysene CHR 228.3 L 3

Benz[e]acephenanthrylene or benzo[b]fluoranthene

BbFA 252.3 S 2B

Benzo[j]fluoranthene BjFA 252.3 S 2B

Benzo[k]fluoranthene BkFA 252.3 S 2B

Benzo[a]pyrene

BaP 252.3 S 2A

Benzo[e]pyrene

BeP 252.3 I 3

Benzo[ghi]perylene BghiP 276.3 I 3

Indeno[1,2,3-cd]pyrene IP 276.3 S 2B

Dibenz[a,h]anthracene DBahA 278.4 S 2A

International Union of Pure and Applied Chemistry (IUPAC) names, ranked according to increasing molecular mass and, for isomers, in alphabetical

order.

As used in this text.

Classification according to International Agency for Research on Cancer (IARC, 1987). Overall Evaluations of Carcinogenicity: An Updating of IARC

Monographs, vols 1–42. IARC Monographs on the Evaluation of Carcinogenic Risks to Humans, Supplement 7. Lyon: International Agency for Research on

Cancer.

Degree of evidence for animal carcinogenicity: I, inadequate; L, limited; S, sufficient.

Overall evaluation of carcinogenicity to humans: 2A, probably carcinogenic; 2B, possibly carcinogenic; 3, not classifiable.

Non-IUPAC, commonly used name.

3,4-Benzopyrene in older publications.

1,2-Benzopyrene in older publications.

4616 POLYCYCLIC AROMATIC HYDROCARBONS

compartments, which they enter mostly via the

atmosphere.

0004 During any formation process, and subsequently in

the matrices to which the population is exposed (air,

water, soil, and food), PAHs are always present as a

class and not as individual compounds, in complex

mixtures also containing other chemical classes.

0005 Most PAHs have no use other than for research

purposes. Exceptions are limited to an occasional

use of some PAHs as intermediates in the production

of plasticizers, pigments, dyes, and pesticides; naph-

thalene is used as a moth-repellant for clothing.

Sources in Foods

0006 In nonprocessed foods, the occurrence is mainly

attributed to the environmental contamination:

deposition of airborne particles (e.g., grain, fruits,

and vegetables), uptake from contaminated soil (e.g.,

potatoes), absorption from contaminated fluvial and

marine waters (e.g., mussels, fish, and shellfish).

Common sources in processed foods are thermal

treatments (namely grilling, roasting, baking, and

frying), and processing procedures. The latter include

especially the drying process by combustion fumes,

e.g., vegetables oils, and the smoking process by

traditional methods.

0007 PAHs may leach into drinking water from coal-tar

or asphalt coatings on storage tanks and water

distribution pipes.

Toxicological Effects

Carcinogenicity of PAHs

0008 The toxicological concern for PAHs is due to their

carcinogenicity; other effects turn out to be by far less

important. The International Agency for Research on

Cancer (IARC) evaluated the carcinogenic evidence

for 43 PAHs. The evidence in experimental animals

was evaluated as ‘sufficient’ for 12 of them, and

‘limited’ for 12 others. No individual PAH could be

evaluated conclusively as a human carcinogen. This is

a consequence of the fact that human exposure, via

both inhalation and ingestion, always occurs simul-

taneously with complex mixtures containing a large

number of PAHs (with variable composition) and

other potentially carcinogenic compounds. Based on

an overall evaluation of available data, however, the

IARC could classify three PAHs (including BaP) as

‘probably’ carcinogenic to humans and nine as ‘pos-

sibly’ carcinogenic (Table 1; five possibly carcino-

genic PAHs are missing from the table and are not

considered in this review, due to the scarcity of their

occurrence data and to their very low, or undetected,

concentrations reported in any matrix). For a number

of PAH mixtures (also containing other potentially

carcinogenic chemicals) occurring in occupational

environments, there is epidemiological evidence of

increased risk for lung cancer and, in some cases,

for skin (following dermal exposure) and bladder

cancers; it is plausible to attribute these risks partially

or predominantly to PAHs.

Carcinogenic Risk of BaP by Ingestion

0009No adequate epidemiological data are available con-

cerning carcinogenicity by ingestion of PAHs or PAH

mixtures. The experimental data are scarce and

limited to BaP. The latter has been shown to be car-

cinogenic in experimental studies when given by diet.

Oral administration of BaP to mice induced gastric

papillomas and squamous-cell carcinomas and in-

creased the incidence of pulmonary adenomas. Other

studies in mice indicated that it can cause carcinomas

distal to the point of application. The incidence of

gastric tumors was 70% or more in mice fed 50–250

ppm BaP for 4–6 months. In another study with rats,

which were fed diets containing BaP, tumors were

observed in the forestomach, esophagus, and larynx.

0010Based on these experiments, the US Environmental

Protection Agency made a quantitative assessment of

carcinogenic risk for oral exposure to BaP which gave a

unit risk of 7.3 10

3

(mgkg

1

) day

1

. This involves

an increased risk of 1 10

5

for the daily ingestion of

about 100 ng BaP per person (1.4 ng BaP kg

1

body

weight). This ingestion value is roughly in the order of

magnitude of the actual BaP intake as estimated in

different studies; the actual BaP intake, however, may

exceed the value of 100 ng by up to fourfold.

0011The ingestion of food is by far the major source of

PAH exposure for nonsmokers. It has been estimated

as contributing up to about 90% of total BaP intake,

excluding occupational and tobacco exposure. The

remaining is attributed to air inhalation and (about

or less than 1%) to drinking water. However, while

there is a great deal of evidence which stresses the

hazard of inhalation and skin contact as routes of

PAH intake, it is less clear what the risk of ingestion

is. (See Smoked Foods: Principles; Applications of

Smoking.)

Limit Values of PAH Concentration in Foods

0012Owing to the potential carcinogenicity of foods con-

taminated by PAHs, some measures have been taken

to limit the PAH content, in particular that due to

food processing. They include legal limits associated

with smoked foods and water, and recommended

limits for refined oils and fats.

0013Smoked food Germany, Austria, and Poland set a

limit of 1 mgkg

1

for BaP in smoked meat and meat

POLYCYCLIC AROMATIC HYDROCARBONS 4617

products. The same limit was also set in Germany for

smoked cheese and cheese products. In the European

Union, the maximum BaP concentration permitted in

foodstuffs as a result of using flavorings, including

smoke flavorings, is 0.03 mgkg

1

(Council directive

88/388/CEE of 22-06-1988). In addition, another

Council directive (91/493/CEE of 22-07-1991) con-

cerning fishery products lays down some health con-

ditions under which these products must be smoked,

and lists wood materials which cannot be burned in

smoking foods. (See Vegetale Oils: Types and Proper-

ties; Composition and Analysis.)

0014 Waters The following limits were set in the Euro-

pean Union to PAH presence in water intended for

human consumption (Council directive 98/83/EC of

3-11-1998): 0.010 mgl

1

for BaP, and 0.10 mgl

1

for

the sum of benz[e]acephenanthrylene, benzo[k]fluor-

anthene, benzo[ghi]perylene, and indeno[1,2,3-

cd]pyrene. BbFA, BkFA, BghiP, and IP.

0015 Refined oils and fats Some European oil industries

set their own guideline values for refined oils and fats:

5 mgkg

1

for the sum of seven higher-molecular PAHs

(BaP, benzo[e]pyrene (BeP), BghiP, dibenz[a,h]anthra-

cene (DBahA), perylene, anthanthrene, coronene),

and 25 mgkg

1

for the sum of 13 PAHs, including

the previous seven, plus another six lower-molecular

PAHs. (See Chromatography: High-performance

Liquid Chromatography; Gas Chromatography;

Supercritical Fluid Chromatography; Spectroscopy:

Visible Spectroscopy and Colorimetry.)

Analysis

0016 The determination of PAHs in food is complex, time-

consuming, and requires experienced personnel.

Nowadays, it is accepted that it has to be performed

under a program of quality control/quality assurance,

with the aim of providing fully reliable results.

PAH Selection

0017 There is no standard list of PAHs to be determined

and the selection performed by each investigator

is commonly arbitrary, based on the available

instrumentation and reference standards. Almost

invariably, BaP has been determined in every investi-

gation, due to its well-known carcinogenicity. Now-

adays, special attention is generally given to the

determination of other carcinogenic PAHs, especially

in health-related studies. Also when other PAH con-

centrations are available, BaP is usually taken as a

reference compound to compare the contamination

and the toxicological potency of different food items.

This is supported by the fact that BaP is by far the

species of higher toxicological concern, due to the

combination of its carcinogenic potency – relatively

to the other PAHs – with its concentration levels.

Sample Preparation

0018Most foods are not homogeneous and must be care-

fully homogenized prior to analysis. Extraction and

clean-up are crucial steps in the determination

because of the very low amounts of PAHs and the

need to separate them from substances which may

interfere during analysis, especially the lipids. The

general scheme shown in Figure 1 has been widely

used, as such or with some modifications which were

later introduced in its application to a wide range

of foods and to total diet samples. Modifications to

the scheme of Figure 1 most commonly involve the

extraction and partitioning solvents (e.g., dimethyl

sulfoxide replacing N,N-dimethylformamide), the

chromatographic sorbent (e.g., XAD-2 resin com-

bined with other sorbents or florisil or alumina com-

bined with silica gel), and thin-layer chromatography

as the clean-up step. The sonication extraction (e.g.,

of plants and smoked foods) has also been used

efficiently; its advantages are the reduced time of

extraction and possibly superior recovery efficiencies

and reproducibilities, but the results depend on

matrix, solvent, and experimental conditions. Con-

ventional chromatographic columns are often substi-

tuted by prepacked commercial cartridges (solid-

phase extraction), which give advantages in terms of

time and solvents consumed, and of reproducibility

performance.

0019Recently, supercritical fluid extraction (SFE: e.g.,

of smoked and broiled fish, and toast) and accelerated

solvent extraction (ASE: e.g., of smoked meat) have

gained attention as rapid alternatives to conventional

liquid extraction.

Sample Analysis

0020Identification and quantification are performed

by capillary gas chromatography (GC) or by high-

performance liquid chromatography (HPLC). In GC

analysis, the most widely used stationary phases

are the methylpolysiloxanes, especially SE-54 (5%

phenyl, 1% vinyl-substituted) and SE-52 (5% phenyl-

substituted) or equivalent phases. A flame ionization

detector is almost universally employed: it has an

excellent response linearity and, coupled with cold

on-column injections, gives an accurate and precise

quantification; because of its nonselectivity, however,

samples need to be highly purified. Mass-spectromet-

ric detectors are powerful tools in identifying and

confirming compounds, and have gained wide accept-

ance. In HPLC analysis, the most used packed mater-

ial consists of silica particles chemically bonded to

4618 POLYCYCLIC AROMATIC HYDROCARBONS

linear C18 hydrocarbon chains. Ultraviolet (UV) and

fluorescence detectors are used, usually arranged in

series. The fluorescence detector is more sensitive,

and its specificity allows for PAH determination in

the presence of nonfluorescing interferences. For

confirmation purposes, much information on the iso-

meric structure may be obtained from UV spectra

acquired during the elution of chromatographic

peaks by the UV diode-array detector.

Standard Methods

0021 Standard methods for BaP in fats and oils have been

prepared by International Standards Organization

(ISO), American Oil Chemists’ Society (AOCS), and

IUPAC. General methods for PAHs in food have

been published by IARC and Association of Official

Analytical Chemists (AOAC).

Occurrence in Foods

0022 Table 2 summarizes the levels of individual PAHs in

various foods, as reported in the literature. The inves-

tigations for which the results are included in the table

were selected on the basis of their representativeness

of typical or (conversely) extreme situations, their

recency (since the 1980s), and the wide spectrum of

PAHs reported. While not exhaustive, the table aims

to give general information on the contamination

levels which may be found and to allow them to be

compared in different foods. A number of investiga-

tions concerning only BaP determination are

not included in the table but are discussed in the

following sections.

0023Levels of individual PAHs generally range from

below 1 mgkg

1

to a few mgkg

1

. Occasionally, they

are in the order of ten, and even hundreds of mgkg

1

0024The highest PAH levels were found in grilled food,

smoked and broiled fish, mussels from polluted

waters, and leafy vegetables grown in areas heavily

exposed to air pollution. Shellfish such as crustaceans

and bivalves do not metabolize PAHs appreciably and

may accumulate high PAH amounts.

Food Smoking

0025There are considerable variations in the PAH contents

of smoked foods, even within the same type of food.

These are due to the variations in the smoke gener-

ation conditions, which include smoke production

temperature, type and comminution of wood mater-

ial, type of generators, time of smoking, and fat con-

tent of products. In general, the higher the smoking

temperature, the more PAHs are formed.

0026High levels of individuals PAHs, and BaP in

particular, were found in smoked fish (BaP, in the

order of 10 mgkg

1

); this may be locally of major

health concern for populations who consume large

Meat, fish, high-protein foods Oils and fats Vegetables, cereals, bread

Methanolic KOH

digestion

Cyclohexane

extraction

Dissolution in

cyclohexane

Acetone

extraction

N,N-dimethylformamide:H

O:cyclohexane

partition

Cyclohexane

back-extraction

Column chromatography

(silica gel, Sephadex LH 20)

Gas chromatography

fig0001 Figure 1 A classical general scheme for the determination of polycyclic aromatic hydrocarbons (PAHs) in food. Adapted from

Grimmer G and Bo

hnke H (1979) Method 4 – Gas chromatographic profile analysis of polycyclic aromatic hydrocarbons in (I) high

protein foods; (II) fats and vegetable oils; and (III) plants, soils and sewage sludge. In: Egan H, Castegnaro M, Kunte H, Bogovski P and

Walker EA (eds) Environmental Carcinogens: Selected Methods of Analysis, vol. 3. Analysis of Polycyclic Aromatic Hydrocarbons in Environ-

mental Samples, pp. 163–173. Lyon: International Agency for Research on Cancer.

POLYCYCLIC AROMATIC HYDROCARBONS 4619

tbl0002 Table 2 Concentrations (mgkg

1

) of selected polycyclic aromatic hydrocarbons (PAHs) in various foods

n PHE FA PY BaA CHR BbFA BkFA BaP BeP BghiP IP DBahA

Meat and meat products

Meat and meat products 4 3.0 0.5–1.1 0.5 0.02–0.5 0.1–0.6 0.04–1.0 0.01–0.2 0.01–0.6 0.03 0.03–0.6 0.01–0.7 0.01

Poultry and eggs

1 0.9 0.5 0.3 0.2 0.1 0.2 0.2

Eggs 1 0.1 ND 0.03 ND 0.4 0.01 0.01 ND

Eggs, after Gulf War

1 18(295) 1.2(3.9) 5.5(27) 4.5(7.8) 5.6(32) 3.5(13) 4.5(6.5) 7.5(19) 1.2(1.5) 8.7(20) 4.7(5.8)

Bacon 1 7.8 0.3 0.05 0.05 3.70 2.5

Sausages 1 0.04–0.1 0.03–0.3 0.05–0.2 0.05–0.1

Smoked meat 1 Tr-0.3

0.01–0.1 Tr-0.1 Tr-0.1

Smoked beef 1 0.02–0.6 0.02–0.4 0.03–0.3 0.04–0.4

Smoked chicken 1 32 16 20 2.1 6.3 4.6 2.6 3.2 ND 1.7 ND

Smoked sausages 2 0.04–0.4 <0.01–0.3 0.06–0.3 0.04–1.4

Grilled sausages 2 3.5–618 1.1–376 1.2–452 0.2–144 0.3–140

ND–92 ND–172

ND–212 ND–81 ND–153 ND–171 ND–8.8

Grilled duck

1 25 20 24 2.4 31 10 5.8 9.2 ND 5.2 ND

Fish and marine products

Fish 4 3.5 0.8–1.8 0.8 Tr-7.5 0.6–2.9 0.1–2.0 0.04–0.7 Tr-4.5 0.1 Tr-0.9 ND–1.6 0.03

Fish, after an oil spill

1 <2–101 <2–123 <2–145 <2 <2 <2–7.6

Fish and shrimps, after Gulf War

1 5.8–87 ND–33 ND–68 0.1–5.3 ND–16 0.1–5.8 ND–5.3 0.2–31 0.3–29 0.2–39

Fish, oil-contaminated sea

1 13 1.5 1.7 0.3 1.7 0.4 0.4 0.8 0.3 0.1 0.1

Oysters 1 2.1–4.2 5.1–17 3.1–12 0.8–3 3.2–8.8

4.5–12

see BbFA 0.4–1.0 2.4–6.3 0.4–0.8 0.3–0.6 0.1–0.2

Trout

1 ND–0.07 0.1–0.4 0.8–2.9 0.2–1.5 0.07–0.3 ND ND ND ND ND

Smoked trout

1 7.6–8.3 27–39 82–175 9.6–16 1.5–2.9 ND–0.08 5.1–8.4 ND 2.0–4.2 3.2–4.0

Smoked fish 3 5–330 1.4–210 1.3–68 ND–86 ND–50 ND–3.9 ND–6.7

ND–40 ND–2.8 ND–25 ND–37

Smoked fish, traditional kilns

1 65 26 20 2.5 2.5 1.2 0.5 1.2 0.7 1.1 <0.1

Smoked fish, modern kilns

1 32 9.1 5.3 0.6 0.6 0.1 0.07 0.1 0.03 ND

Smoked or canned oysters and mussels 1 1.9–20 4.5–19 2.6–11 0.8–21 3.9–31

1.2–24

see BbFA 0.2–12 0.7–7.6 0.3–5.7 0.2–6.4 <0.1–0.5

Broiled fish 1 320 1080 390 390 400

Vegetables

Kale 1 117 70 15 62 4.2 7.9 7.7 7.9 1.0

Lettuce 4 0.5–12 0.09–28 0.4–18 0.05–4.6 0.8–4.0 0.1–7.3 ND–17 0.007–6.2 0.07–6.7 0.02–11 0.1–8

Lettuce, industrial area 1 28 6.1 3.7 5.6 10 2.4

Potatoes

1 ND 0.4 0.8 0.2 0.1 ND 0.1 ND

Potato products

1 3.0 0.6 0.1 ND 0.6 0.3 0.3 0.9 0.6

Tomatoes 2 0.09 0.4 0.006–0.3 0.1–0.5 0.008 0.003 0.003–0.2 0.2 ND 0.04

Soups

1 ND ND 0.4 0.05 0.08 ND ND ND

Fruits and confectionery

Fresh fruit

1 7.8 3.6 0.5 0.5 0.1 0.1 ND ND ND

Apples 1 2.4 3.5 0.3 ND 0.3 0.08 0.5 0.02

Canned fruit and juices

1 ND 1.0 ND ND 0.1 0.1 0.1 0.1 ND

Nuts 1 10(17) 1.3(3.0) 0.1(4.2) 4.0(69) 0.2(0.4) ND(0.1) ND(0.2) ND(0.4) ND(0.4)

Biscuits, pudding, and cakes 2 2.9 0.5–3.6 0.6–2.4 0.08–2.7 0.09–2.8 0.03–1.3 0.04–1.4 0.04–2.2 0.08–2.9 0.1–2.5 0.1–3.2

Sugar and sweets 1 ND(3.2) 0.7(2.3) 0.2(4.2) 0.7(36) 0.2(3.5) 0.1(0.5) 0.1(0.4) ND(0.2) ND(0.2)

Cereals

Breakfast cereal 1 0.2–0.6 0.3–1.2 0.06–0.2 0.02–0.05 0.02–0.07 0.03–0.05 0.06–0.2/ 0.06–0.08 0.08–0.15 <0.01

Bread 3 3.3 0.2–2.8 ND–0.9 0.1–0.8 0.1–1.9 0.04–1.2 0.02–0.06 0.02–0.8 0.06–0.1 0.01–0.5 0.11–0.6 <0.01–0.01

Pasta, macaroni, and rice 2 2.1 2.5–3.9 ND 0.03–0.4 1.3–1.9 0.04–1.0 0.02–0.5 0.017–0.8 ND–0.6 0.5

Noodles and pizza 1 4.2 3.7 0.5 2.0 0.5 0.1 0.2 0.5 0.3

Pizza in a wood-burning oven 1 0.2 0.6 9.1 3.0 0.04 0.02 0.02 0.06

Oils and fats

Olive oils 3 0.4–38 Tr-15 ND–14 0.03–0.9 0.4–1.5 0.3–1.4 0.06–0.5 0.1–1.3 <1 ND–1.9 0.3–2.0 ND–0.1

Extra virgin olive oils 1 1.7–53 Tr-53 0.4–28 Tr-10 Tr-2.3 Tr-1.3 Tr-0.5 Tr-1.2 Tr-0.7 Tr-0.6 Tr-0.3

Various unrefined oils

1 ND–69 0.2–18 0.1–14 ND–6.1 0.1–8.6

ND–8.9

see BbFA ND–4.1 ND–3.8 ND–4.2 ND–4.3 ND–0.2

Coconut oil, deodorized 1 8.7 23 29 5.7

see BaA 1.0

see BbFA 0.2 0.4 <0.1 ND

Corn oil 1 0.1 ND ND ND ND 0.09

see BbFA 0.02 0.04 0.1 ND 0.03

Butter 1 0.1 1.8 0.6 ND 0.02 0.03 0.02 ND

Margarine 3 <0.2–6.0 0.09–9.0 <0.1–15 <0.1–5.2 <0.2–7.5 <0.2–9.2 <0.1–11 0.05–6.0 0.09–6.1 0.02–11 0.03–9.7 0.05–9.2

Beverages

Wine 2 0.08 ND 0.003 ND Tr-0.04 Tr-0.01 Tr- 0.009 ND–0.03 ND ND

Beer 2 0.04 ND 0.1 ND Tr-0.2 ND–0.1 ND–0.07 ND–0.2 ND–0.1 ND–Tr

Coffee 1 1.2 ND 0.1 ND 0.08 0.02 0.01 0.01

Tea infusion

1 0.2–0.7 0.007–0.03 0.02–0.2 0.003–0.043 0.002–0.02 0.007–0.056 0.007–0.03 0.005–0.02

Milk 2 ND 0.1–0.2 0.04–0.2 0.01 ND–1.5 0.01–0.06 0.003–0.03 0.01–0.02 ND 0.01–0.03 ND ND

Milk, after Gulf War

1 3.0(9.8) 3.4(12) 35(145) 2.4(3.7) 8.6(32) 3.1(4.4) ND 1.5(1.5) ND ND ND

A large part of data was adapted from International Programme on Chemical Safety (1998). Selected Non-heterocyclic Polycyclic Aromatic Hydrocarbons. Environmental Health Criteria 202. Geneva: World Health

Organization. Unless otherwise specified, an individual value is the mean concentration (if n ¼1) or the only available mean concentration (if n > 1). Concentrations in parentheses are maximum values.

n,numberofinvestigations;ND,notdetected;Tr,traces;forPAHabbreviations,see Table 1.

Maximum concentrations (mean concentrations were mostly ND).

Kuwait, from locally reared animals.

Grilling time: 0.5 h.

Arabian Gulf.

Kuwait.

Red Sea coast; oil operations and heavy ship traffic.

‘Trout’ and ‘smoked trout’ were investigated within the same study.

‘Traditional kilns’ (27 samples, three kilns) and ‘modern kilns’ (35 samples, five kilns) were investigated within the same study; mean concentrations are reported.

Olive, safflower, sunflower, maize germ, sesame, linseed, wheat germ oils.

Concentrations in mgl

1

In sum with triphenylene.

In sum with CHR and triphenylene.

In sum with BjFA and BkFA.

In sum with BjFA.

In sum with dibenz[a,c]anthracene.

quantities of these products. Considerable amounts

of PAHs were found in home-smoked meat in Iceland,

with most of BaP detected in the superficial layers of

the meat, and in smoked cheese too. The highest BaP

concentrations were found in samples of smoked

cereals (up to 160 mgkg

1

) and smoked teas (up to

110 mgkg

1

0027 Traditional smoking techniques, in which smoke

from incomplete wood burning comes into direct

contact with the product, can lead to extensive con-

tamination with PAHs. Hence, smoke flavorings are

used as an alternative. Current commercial smoking

practices appear to be effective in controlling the

deposition of PAHs. In a recent Spanish survey of

commercial smoked products, BaP was found at low

levels in almost all samples: up to 0.3 mgkg

1

in meat

products and up to 0.9 mgkg

1

in cheese and in fish,

with the exception of 2.5 mgkg

1

in a sample of

smoked sardine. The oil associated with the fish, if

any, may be more contaminated than the fish itself,

possibly due to the PAH leaching from the fish.

0028 In a German survey conducted in the 1990s, PAH

concentrations were compared between 27 smoked

fishery products from traditional smoking kilns and

35 from modern smoking kilns with external smoke

generation. The BaP levels from the modern kilns were

one order of magnitude lower (on average, 0.1 mgkg

1

)

than by the traditional systems (1.2mgkg

1

Meat and Meat Products

0029 The amount of PAHs formed during cooking depends

markedly on the method of cooking and the condi-

tions. In particular, PAH formation during charcoal

grilling is dependent upon the fat content of the meat,

the time of cooking, and the temperature.

0030 This formation may be due to various causes: the

incomplete combustion of charcoal, the transform-

ation of some food components such as triglyceride

and cholesterol, or – the most likely source of high

PAH levels – the melted fat of the meat. Actually,

during charcoal grilling at high temperatures, the fat

drippings fall on the hot coals where they are pyro-

lyzed, producing PAHs which are then volatilized and

deposited onto the meat surface.

0031 An investigation of the effect of the method, includ-

ing broiling on electric and gas heat, charcoal

broiling, and broiling over charcoal with a no-drip

pan, showed that PAH formation may be minimized

by avoiding direct contact of the food with the

cooking flame, cooking meat at lower temperatures

for longer periods, and using meat with a low fat

content.

0032 The total concentration of six carcinogenic PAHs

in a lamb sausage increased from 1.9 mgkg

1

when

grilled over charcoal under standard barbecue

practices (distance between fire and meat 10 cm;

temperature at the surface of the meat 200–250



to 13.2 mgkg

1

when heavily grilled for a prolonged

time.

0033An experiment on PAH formation in duck meat

during various processing methods showed the

highest concentrations of carcinogenic PAHs were

due to smoking (1 m distance between smoke gener-

ation source and meat), followed by charcoal grilling

(1 m distance between charcoal and meat) and

roasting (at 200



C); no carcinogenic PAHs were

detected in samples subjected to steaming or to

flavoring by liquid smoke. The BaP concentration

during smoking increased from 6.9 mgkg

1

after

0.5 h to 13.9 mgkg

1

after 3 h.

Fishes and Marine Products

0034Processing and cooking may increase PAH levels by

the same routes described above for meats. The

highest levels of BaP and other PAHs were generally

found in smoked fishes, and especially in the smoked

skin. In a study of commercial Baltic herrings, BaP

was found at about 40 mgkg

1

in a smoked specimen,

but at a level one order of magnitude higher in a

broiled one (about 400 mgkg

1

, which is the highest

level of contamination reported). High concentra-

tions are also found in marine products from contam-

inated sea.

Vegetables

0035The differences in PAH content may be due to vari-

ations in the ratio between the surface area and the

weight, to location (rural or industrialized) or to

growing season.

0036It is recognized that broad-leaved vegetables may

have particularly high levels of PAHs, due to the

deposition of airborne particulate matter. The im-

portance of atmospheric pollution was shown by the

high levels detected in lettuce grown close to a high-

way, with levels decreasing with distance from the

road. The PAH profiles in lettuce were found to be

similar to those in ambient air, confirming the depos-

ition of airborne particles as the main source of

contamination. In an investigation near a coking

plant, PAH levels in vegetables with large, rough

leaf surfaces (spinach and lettuce) were found to be

10 times higher than in other vegetables (carrots and

beans), and this was likely due to deposition from

ambient air.

0037The effect of washing vegetables on reducing PAH

contamination due to vehicle exhaust appears contro-

versial: in an investigation on kale, PAH content

was not reduced other than at levels lower than

about 10% (BaP, 10%). Conversely, in an experiment

with lettuce, the higher-molecular PAHs were

4622 POLYCYCLIC AROMATIC HYDROCARBONS

considerably reduced (BaP, 67–95%). In no study,

however, were lower-molecular PAHs significantly

affected by washing.

003 8 In an experimental comparison of growth of terres-

trial plants in a ‘clean-air’ chamber and in the open

field, the contamination was shown to be due almost

exclusively to airborne PAHs and not to synthesis by

plants.

Cereals and Dried Foods

0039 Growing crops (wheat, corn, oat, barley) in industri-

alized areas increases PAH levels in comparison to

more remote areas. Grain samples from a heavily

industrialized area contained 10 times more PAHs

than samples from areas remote from industry. The

growth of rye near a high-traffic highway resulted in

PAH contamination, which decreased slightly 7–25 m

away from the road.

004 0 Drying by combustion gases was also found to

increase contamination by three- to 10-fold. In an

experiment with wheat, drying over a light fuel oil

flame increased the BaP deposition from six- to 130-

fold depending on the degree of exposure.

Oils

0041 The presence of PAHs in vegetable oils is due to

contamination from technological processes (namely,

smoke drying of oil seeds or contaminated extraction

solvents) or to environmental contamination (e.g.,

traffic exhaust or industrial emissions).

0042BaP in olive oils is commonly within the 1 mgkg

1

level; higher levels may be present if the oils are from

plants exposed to industrial emissions or if they are

blended with previously contaminated vegetable oils.

0043The refining of olive oils (especially the deodoriza-

tion step) has a marked reducing effect on the light

PAHs but not on the heavy ones. The latter may be

reduced by treatment with activated charcoal.

0044High PAH levels may be found in oil seeds. They

are usually due to the process of direct drying the

seeds, using wood or oil as a fuel. BaP at levels up to

25 mgkg

1

were found in corn oils. The PAH content

of oil seeds is drastically reduced during refining,

particularly by treatment with activated charcoal.

This refining method is now widely used.

Dietary PAH Intake

0045Table 3 shows the dietary intake of PAHs, as esti-

mated from different studies in three European coun-

tries. The intakes were calculated on the basis of food

consumption surveys, except in one Dutch study

where portions of a 24-h intake of food were pro-

vided by the participants and analyzed. There are

numerous differences between the diets of northern

and southern Europe and the criteria adopted in

tbl00 03 Table 3 Dailyintakeofselectedpolycyclicaromatichydrocarbons(PAHs)intotaldiet,asestimatedinvariouscountries(meanand,

inparentheses,whereavailable,maximumvalues)

PAHIntake( mgperson

1

)

TheNetherlands

b,c

Italy

c,d

Rangeofmeanvalues

PHENG2.69(5.13)NG

FA0.991.32(2.11)–2.7(10.4)4.221.0–4.2

PY1.091.6(5.1)1.731.1–1.7

BaA0.220.16(0.48)–0.28(0.65)0.41–1.290.2–1.3

CHR0.51.19(3.90)–1.2(5.0)1.46(1.70)–2.200.5–2.2

BbFA 0.18 0.33 (0.59) 0.65 0.2–0.6

BkFA 0.06 0.12 (0.24) 0.17 0.06–0.2

B[bþjþk]FA >0.24 >0.45 1.10 >0.2–1.1

BaP 0.25 0.08 (0.35)–0.20 (0.42) 0.17 (0.32)–0.37 0.08–0.4

BeP 0.17 0.14 (1.2) NG 0.1–0.2

BghiP 0.21 0.16 (0.58)–0.28 (1.03) 0.02 0.02–0.3

IP ND 0.16 (1.2)–0.27 (0.55) 0.16 (0.20) ND–0.3

DBahA 0.03 0.04 (0.53) 0.08 (0.17) 0.03–0.1

ND,notdetectedinanyfoodgroup;NG,notgiven;PAHabbreviations:see Table 1.B[bþjþk]FA:sumofBbFA,BjFAandBkFA;BjFAwasnotdetermined

in any study.

From Dennis MJ, Massey RC, McWeeny DJ, Knowles ME and Watson D (1983) Analysis of polycyclic aromatic hydrocarbons in UK total diets. Food and

Chemical Toxicology 21: 569–574.

From De Vos RH, Van Dokkum W, Schouten A and De Jong-Berkhout P (1990) Polycyclic aromatic hydrocarbons in Dutch total diet samples (1984–1986)

Food and Chemical Toxicology 28: 263–268; Vaessen HAMG, Schuller PL, Jekel AA and Wilbers AAMM (1984) Polycyclic aromatic hydrocarbons in selected

foods: Analysis and occurrence. Toxicological and Environmental Chemistry 7: 297–324.

When a range is reported, it refers to two different studies.

From Turrio-Baldassarri L, Di Domenico A, La Rocca C, Iacovella N and Rodriguez F (1996) Polycyclic aromatic hydrocarbons in Italian national and

regional diets. Polycyclic Aromatic Compounds 10: 343–349; Lodovici M, Dolara P, Casalini C, Ciappellano S and Testolin G (1995) Polycyclic aromatic

hydrocarbon contamination in the Italian diet. Food Additives and Contaminants 12: 703–713.

POLYCYCLIC AROMATIC HYDROCARBONS 4623

the surveys are not homogeneous. Consequently, the

intakes estimated in different studies cannot be dir-

ectly compared and have to be considered as a rough

estimate of the actual intakes. Notwithstanding these

limitations, it is worth noticing that they are generally

of the same order of magnitude and the differences

are relatively small compared with the variation in

cancer potency estimates.

The Contribution of the Different Food Groups

004 6 The contribution of different food groups to the total

dietary intake of PAHs was estimated in the UK

(Table 4).

0047 The major contributors were the oil-and-fats group

and the cereals group. The former has the highest

individual PAH levels, but the latter, although never

showing high individual PAH levels, is a major

contributor due to its relative weight in the total

diet. Although several studies indicated quite large

amounts of PAHs in smoked meat and smoked fish,

these products made a very small contribution to the

pertinent food groups and these in turn were not

major components of the diet. Consequently, at least

in areas where eating barbecued food is an infrequent

activity, this provides a very small part of the dietary

intake of PAHs. The third major contributor was

vegetables, and this was likely due to the atmospheric

fallout of particle-bound PAHs.

0048 These results were substantially confirmed in a

subsequent study of the Dutch diet: cereal products

were found to contribute most to the daily intake of

PAHs (again attributed to the high consumption

share), followed by sugar-and-sweets and by oils

and fats. It was not possible to explain the surpris-

ingly large share of the sugar-and-sweets group be-

cause none of the constituents (sugar, chocolate

products, jellies, licorice) was suspicious with regard

to high PAH levels. The relatively high contribution

of the oils-and-fats group was at least partly attrib-

uted to the well-known elevated PAH concentrations

possibly present in vegetable oils. Nuts, which were

included in this group, contributed 6% to the total

PAH intake, and this was most likely due to the

roasted peanuts.

0049Cereals were also found to be the highest contribu-

tors in a Swedish study (where they were followed by

vegetables, and by oils and fats), and in an Italian one.

0050A more accurate comparison of the results of all

these studies is not possible due to the differences in

the reporting criteria adopted.

Seealso: Analysis of Food; Cancer:Carcinogensinthe

FoodChain; Carcinogens:CarcinogenicityTests;

Chromatography:High-performanceLiquid

Chromatography;GasChromatography; Dietary

Surveys:SurveysofNationalFoodIntake; Flavor

(Flavour) Compounds:ProductionMethods;

Legislation:InternationalStandards; Smoked Foods:

ApplicationsofSmoking;Production; Smoking, Diet, and

Health