L.I. Medved’s Research Center of Preventive Toxicology, Food and Chemical Safety, Ministry of Health, Ukraine (State Enterprise), Kyiv, Ukraine
ABSTRACT. Objectives. To conduct analysis of PAH findings obtained by different international research organizations and institutions. To compare European and Ukrainian laws regulating contamination of food with PAH. Methods and Materials. Analysis of scientific sources and European and Ukrainian legal acts regulating contamination of food with PAH. Research on contamination of food with PAH.
Results and Discussion. According to European Food Safety Authority findings (2008) a total of 9714 foodstuff samples were investigated for one or more 16 priority PAH concentration. Results for the full set of 16 PAH were reported in 823 foodstuff samples, for 15 SCF priority PAH – in 1375 samples, and PAH 8 – in 4065 samples. Benzo[a]pyrene was detected in approximately 50% of all samples tested, ranging from not detected to 100% depending on the foodstuff group involved. In about 30% of samples tested for SCF priority PAH the carcinogenic and genotoxic PAH were detected despite the negative test results for benzo[a]pyrene. The CONTAM Panel came to a conclusion that benzo[a]pyrene is not an unconditional indicator of PAH occurrence in foodstuffs.
Based on currently available data concerning PAH occurrence and toxicity, the CONTAM Panel concluded that PAH4 (benzo[a]pyrene, benz[a]anthracene, benzo[b]fluoranthene, chrysene) and PAH8 (benzo[a]pyrene, benz[a]anthracene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[ghi]perylene, chrysene, dibenz[a,h]anthracene and indeno[1,2,3-cd]pyrene constitute the most indicative PAH in foodstuffs with PAH8 not providing much added value compared to PAH4.
The findings of the research conducted at the Research Center of Toxicology revealed that benzo[a]pyrene content in two samples of sunflower oil exceeded its maximum level. The PAH content in the unrefined crude soybean oil test sample exceeded the maximum level for both benzo[a]pyrene and the sum of three PAH. Considering the sources, conditions of PAH formation and oil production process peculiarities, it can be assumed that PAH accumulation in oil occurs due to improper drying of oilseeds.
In Ukraine, as part of the implementation of the EU Association Agreement with Ukraine, the work is in progress to harmonize national legislation on PAH regulation with European documents.
Conclusions. Given the high hygienic importance of polycyclic aromatic hydrocarbons as common carcinogenic foodstuff contaminants, it is necessary to assess health risk factors associated with above-mentioned compounds content in foodstuffs. Special measures to reduce their level in diets for the population should be developed and implemented.
Key Words: polycyclic aromatic hydrocarbons, benzo[a]pyrene, safety, risks, harmonization.
Introduction. Foodstuff and food commodity safety is one of relevant public health issues and constitutes a priority task of state policy on healthy nutrition. It is also a necessary precondition for providing sanitary and epidemiological well-being for the population.
One of the major ways of chemical contaminants entering the human body is through food commodities. According to Codex Alimentarius Commission documents, the contaminant is any substance which is not intentionally added to food or feed at any stage of life-cycle production [1]. The most widespread anthropogenic contaminants are heavy metals, nitrosamines, pesticides, hormones, antibiotics and polycyclic aromatic hydrocarbons (PAH).
Polycyclic aromatic hydrocarbons are organic compounds whose molecules contain only tree or more condensed aromatic rings which form different combinations. The commonest are benzo[a]pyrene, benz[a]anthracene, benzo[b]flu-oranthene, chrysene. They are relatively insoluble in water but highly lipophilic. Polycyclic aromatic hydrocarbons are resistant to physical, chemical, biochemical exposures. PAH toxicity results from their mutagenic, carcinogenic and teratogenic properties [2, 3].
These compounds are primarily formed as a result of the incomplete combustion or pyrolysis of organic materials during different industrial activities. Until recently, the scientists believed that high temperature pyrogenic processes which occur at 700 – 800 °С were the only PAH sources in food and feed. Meanwhile, further data show that there are other contamination sources which are formed at lower temperatures. It is argued and proved by special experiments findings that PAH can be synthesized by certain plants [4].
The major PAH sources are considered to be vehicle exhaust, coke manufacturing from coal, steel industry processes, fires, coal, wood, tobacco, crude oil and crude oil products combustion, heat-electric stations and waste incinerators operation, and other. PAH are produced in large amounts during thermal processing of food (grilling, roasting, frying) as well as home or commercial food smoking. Polycyclic aromatic hydrocarbons are one of the commonest toxicants in the environment.
PAH enter the human body through different routes. In non-smokers, PAH are mainly consumed with food while in cigarette and cigar smokers, due to their harmful habit. Foodstuffs can be contaminated with PAH from the environment and after industrial processing. Grains (due to their high concentration in rations), plant fats and oils (due to high concentration of PAH in that commodity group) are also dangerous source. As a rule, despite the high concentration of PAH, smoked fish and meat, foodstuffs, grilled over an open fire, have no substantial impact on the levels of PAH intake provided they are consumed in small amounts. However, if the diet contains more of such foodstuffs, the level of PAH intake is more considerable [5, 6].
Aim of the Research is to analyze scientific investigations of PAH conducted by different international organizations and institutions. To compare European and Ukrainian laws regulating contamination of food with PAH.
Methods and Materials. Analysis of scientific sources and European and Ukrainian legal acts regulating contamination of food with PAH. The research conducted on contamination of food with PAH.
Results and Discussion. Despite the variety of PAH, most research works, analyses and scientific papers focus on the limited amount of PAH. The most frequent ones are 16 main compounds – 16 EPA PAH: benz[a]anthracene, benzo[b]fluoranthene, benzo[j]fluoranthene, benzo[k]fluoranthene, benzo[ghi]perylene, be-nzo[a]pyrene, chrysene, cyclopentha[cd]pyrene, dibenz[a,h]anthracene, dibenzo[a,e]pyrene, di-benzo[a,h]pyrene, dibenzo[a,i]pyrene, diben-zo[a,l]pyrene, indeno[1,2,3-cd]pyrene, 5-me-thylchrysene, benzo[c]fluorine).
In the last ten years PAH were evaluated according to the International Programme on Chemical Safety (IPCS), the Scientific Committee on Food (SCF) and Joint FAO/WHO Expert Committee on Food Additives (JECFA). In 2002 the SCF concluded that 15 PAH, namely benz[a]anthracene, benzo[b]fluoranthene, ben-zo[j]fluoranthene, benzo[k]fluoranthene, benzo-[ghi]perylene, benzo[a]pyrene, chrysene, cyclo-pentha[cd]pyrene, dibenz[a,h]anthracene, di-benzo[a,e]pyrene, dibenzo[a,h]pyrene, diben-zo[a,i]pyrene, dibenzo[a,l]pyrene, indeno[1,2,3-cd]pyrene, 5-methylchrysene, with the exception of benzo[c]fluorine, have shown clear evidence of mutagenicity and genotoxicity in somatic cells in experimental animals in vivo. They have also shown clear carcinogenic effects in various types of biological tests on experimental animals. Thus, the SCF substantiated that this compound should be regarded as potentially genotoxic and carcinogenic to humans and therefore they are a priority group for assessing the possible long-term risks from PAH in food.
Based on the IPCS and the SCF evaluation results and taking the advanced findings into consideration, the JECFA reassessed PAH in 2005. The JECFA concluded that 13 PAH are genotoxic and carcinogenic.
With the exception of benzo[ghi]perylene and cyclopentha[cd]pyrene, the PAH compounds were the same as those identified by the SCF. In addition, the JECFA recommended to include benzo[c]fluorine into future analyses as there is not enough data on its occurence in foodstuffs but rat studies demonstrate that benzo[c]fluo-rine can contribute to the formation of lung tumors after oral exposure [7].
In 2008 the experts of European Food Safety Authority published the data on PAH contamination in food (the EFSA Panel on Contaminants in the Food Chain (CONTAM Panel)) [7]. The CON-TAM Panel covered 15 PAH identified by the SCF and additionally benzo[c]fluorine as recommended by the JECFA (PAH16). Special attention was paid to eight carcinogenic and genotoxic PAH used in carcinogenity studies, which provided the basis of the SCF and JECFA risk assessment: benzo[a]pyrene, benz[a]anthra-cene, benzo[b]fluoranthene, benzo[k]fluoran-thene, benzo[ghi]perylene, chrysene, dibenz-[a,h]anthracene, indeno[1,2,3-cd]pyrene (PAH8).
In total, 9714 food samples were analyzed for one or several of 16 priority PAH. 16 PAH were detected in 823 food samples, 15 SCF priority PAH – in 1375 food samples, and PAH8 – in 4065 food samples. Benzo[a]pyrene occurred in about 50 % of all samples analyzed with the frequency varied from 0 % to 100 % for different food categories. Despite negative results for benzo[a]pyrene, carcinogenic and genotoxic PAH were detected in 30 % of food samples analyzed for 15 SCF priority PAH.
CONTAM Panel found that benzo[a]pyrene was not a suitable indicator for the occurrence of PAH in food. Based on available data on PAH occurrence frequency and toxicity, CONTAM Panel concluded that PAH4 (benzo[a]pyrene, benz[a]anthracene, benzo[b]fluoranthene, chrysene) and PAH8 (benzo[a]pyrene, benz[a]-anthracene, benzo[b]fluoranthene, benzo[k]flu-oranthene, benzo[ghi]perylene, chrysene, di-benz[a,h]anthracene, indeno[1,2,3-cd]pyrene) were the most suitable indicators for polycyclic aromatic hydrocarbons in food, with PAH8 not providing much added value in comparison with PAH4.
In accordance with these findings, in 2011 the European Commission reviewed a list of foodstuffs in which maximum limits for PAH were set which was stated in amendments to Commission Regulation (EC) № 1881/2006 of 19 December 2006 setting maximum limits for certain contaminants in foodstuffs [8]. New maximum levels for the sum of four compounds (PAH4) were set. Such approach guaranteed that PAH occurrence in foodstuffs is maintained at levels of low risk for human health, and PAH can be controlled in those samples which are negative for ben-zo[a]pyrene but contain other PAH. For comparability studies in previous and future data, the separate maximum level for benzo[a]pyrene was set.
Since 2014 in Europe maximum limits for benzo[a]pyrene and the sum of benzo[a]pyrene, benz[a]anthracene, benzo[b]fluoranthene and chrysene in smoked meat products, smokes fish and fishery products, cocoa beans and derived products and came into force [8].
Maximum levels for polycyclic aromatic hydrocarbons must be safe and as low as reasonably achievable, based upon good manufacturing and agricultural and fishery practices.
In Ukraine there are current State Hygiene Regulations and Norms of “Regulation of 13.05.2013 № 368 setting maximum levels for certain contaminants in foodstuffs” approved by the Order of the Ministry of Health of Ukraine [9]. According to this document, the occurrence of benzo[a]pyrene and the sum of three PAH (benzo[a]pyrene, benz[a]anthracene, benzo[b]-fluoranthene) is monitored. There is a list of foodstuffs with limited PAH levels:
– oils and fats (excluding cocoa butter and coconut oil) intended for direct human consumption or use as an ingredient in food;
– cocoa beans and derived products;
– coconut oil intended for direct human consumption or use as an ingredient in food;
– smoked meat and smoked meat products;
– muscle meat of smoked fish and smoked fishery products, smoked sprats, smoked bivalve mollusks;
– baby foods for infants and infant formulae and follow-on formulae;
– foodstuffs for special medical purposes for infants.
– Unlike the Ukrainian laws, Commission Regulation (EC) № 1881/2006 the legislative limits are laid for benzo[a]pyrene and the sum of PAH4 with the list of food groups including the following:
– cocoa fibre and derived food products intended for use as an ingredient in food;
– banana chips;
– food supplements containing plant extracts and plant products;
– food supplements containing propolis, royal jelly, spirulina and their products;
– dried herbs and dried spices with the exception of cardamom and smoked peppers.
It is necessary to note that according to article 229 of the Action plan on implementation of the Association Agreement between Ukraine, of the one Part, and the European Union, the European Atomic Energy Community and their Member States, of the Other Part, approved by the Cabinet of Ministers of Ukraine Resolution №1106 of 25 October 2017, the Ministry of Health of Ukraine has made a draft of the order On Amendment of State Hygiene Regulations and Norms of the Regulation setting maximum levels for certain contaminants in foodstuffs intending to harmonize it with Commission Regulation EC № 1881/2006.
The document setting the PAH levels in drinking water in Ukraine is GSanPiN 2.2.4-171-10 Hygienic requirements for drinking water intended for human consumption [10]. The maximum levels for benzo[a]pyrene in pipe water are set as ≤ 0,005 µg /dm3, in bottled water and borewells – < 0,002 µg /dm3.
The Council Directive 98/83/EC of 3 November 1998 on the quality of water intended for human consumption [11] set the limit values for benzo[a]pyrene of 0.01 µg /L, and 1,10 µg /L for the sum of benzo[b]fluoranthene, benzo[k]fluo-ranthene, benzo[ghi]perylene, indeno[1,2,3-cd]pyrene.
The Research Center of Toxicology (RCT) based on State Enterprise “Scientific Center of Preventive Toxicology, Food and Chemical Safety named after Academician L.I. Medved, Ministry of Health of Ukraine and accredited according to DSTU ISO/IEC 17025:2017. The RCT accreditation deals with investigations of foodstuff safety including PAH occurrence in food.
The following methods of analysis for PAH in foodstuffs are used:
– DSTU 4689:2006 Foodstuffs. Methods of benzo[a]pyrene mass fraction measurement;
– ISO 15753:2006(Е) Animal and vegetable fats and oils – Determination of polycyclic aromatic hydrocarbons;
– DSTU ISO 17993:2008 Water quality. Detection of 15 polycyclic aromatic hydrocarbons (PAH) in water using the method of high-performance liquid chromatography with fluorescence detection following liquid-liquid extraction;
– МІ.С3.7.2.01-049 PAH detection in foodstuffs using the method of HPLC.
The investigation results can be found in the Table below.
As shown in the table above, all food samples in the investigation, with the exception of three samples of oils (sunflower and soybean), met the requirements of State Hygiene Regulations and Norms of the Regulation setting maximum levels for certain contaminants in foodstuffs. The maximum levels for benzo[a]pyrene and the sum of three PAH in all food samples did not exceed the quantitative standard norms of the method.
The occurrence of benzo[a]pyrene in both sunflower oil samples did not exceed its maximum level. The PAH occurrence in the investigated sample of crude soybean oil exceeded maximum levels for both benzo[a]pyrene and the sum of three PAH.
Considering the sources, conditions of PAH formation and peculiarities of oil production technological process, it can be assumed that PAH accumulation in oils occurs due to improper drying technologies in oilseed processing industry.
It is generally believed that PAH enter the oilseeds during heated-air drying process with smoke containing products from incomplete combustion in which polycyclic aromatic hydrocarbons are identified as by-products. It can be concluded that all amount of benzo[a]pyrene is released from seeds and distributed among end products in a manufacturing process, with 90 – 95 % of it absorbed in oil while oilcake contains only minor part ranging from 5 % to 10 %. Such distribution is common regardless the oilseed crops type. It is estimated that refined oil contains less of the abovementioned hydrocarbons than the crude oil does [4, 6].
Conclusions. Thus, the level of PAH occurrence in foodstuffs depends on the type of technological process, its parameters, foodstuff chemical composition, ingredients added in the manufacturing process, probability of contamination from the environment. As a consequence, this process is deemed to be controlled.
An important stage of human health risk management is considered to be a hygiene assessment of foodstuffs contamination levels with polycyclic aromatic hydrocarbons which results in making legal decision on their circulation as well as the necessity of setting and regulation reassessment of maximum levels for these contaminants.
Health risk assessment of PAH occurrence in foodstuffs should be performed through a comprehensive approach which deals with the sources of PAH in the habitat and the conditions contributing to their generation in the manufacturing process. Therefore, it is necessary to make efforts to prevent contamination of environment with PAH namely to reduce their formation level through environmental protection activities including controlling their content in the environmental factors (air, drinking water, soil) [12]. Contamination of food with PAH should be controlled source-directed measures, for example, filtering the smoke from relevant industries (cement plants, incinerators and metallurgy) and limiting the exhaust fumes of PAH from cars. Appropriate practices, including the selection of appropriate farmlands or fishing waters can also reduce the environmental contamination of raw materials with PAH.
PAH detection in foodstuffs using the method of HPLC
Regarding PAH formation in food industry, the main contamination sources are smoking, drying, frying, baking, and grilling. Presence of PAH in vegetable oils can also originate from oil seeds smoking and drying prior to oil extraction. In these cases, Joint FAO/WHO Expert Committee on Food Additives recommends to take measures to reduce food contamination with PAH during the processes of smoking and drying by replacing direct smoking (with smoke developed in the smoking chamber, traditionally in smokehouses) with indirect smoking. These recommendations are laid out in CAC/RCP 68-2009 Code of practice for the reduction of contamination of food with polycyclic aromatic hydrocarbons (PAH) from smoking and direct drying processes [6].
Physical and chemical properties of foodstuffs are important for preventing the risks of PAH formation in the food production process. High content of fat in foods or using fat in the production process leads to increasing the level of these compounds in the end products. Temperature control in the process of cooking temperature and keeping distance between the source of heating and foodstuffs contribute to decreasing levels of PAH formation.
Thus, considering high-hygienic significance of the processes mentioned above polycyclic aromatic hydrocarbons are common contaminants of food. They possess carcinogenic properties; therefore, it is necessary to assess health risk factors connected with presence of these compounds in foodstuffs. It is also important to develop and take measures to reduce their levels in food intake of the population.
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Received 01/23/2020