Polycyclic aromatic hydrocarbons in smoked fish – a critical review

Among hundreds of components, wood smoke also contains at least 100 polycyclic aromatic hydrocarbons (PAH) and their alkylated derivatives. Many of them are carcinogenic. Benzo[α]pyrene (BaP) is regarded as a marker of the carcinogenic PAH in smoke and smoked fish, although in olive residual oil the maximum level of 2 μg/kg for each of the eight most carcinogenic PAHs, including BaP, has been set. Contemporary analytical procedures based on extraction of the hydrocarbons from the matrix, clean-up procedure, separation by gas chromatography (GC) or high performance liquid chromatography (HPLC), followed by detection and quantification by mass spectrometry (MS) or fluorescence detectors (FLD), respectively, make it possible to determine individual PAH in smoked foods at concentrations of the order of 0.1 μg/kg or even 0.01 μg/kg. Heavily smoked fish from traditional kilns, especially their outer parts, may contain up to about 50 μg BaP/kg wet weight, while the meat of mild hot-smoked fish, from smokehouses supplied with conditioned wood smoke from external generators, contains only about 0.1 μg/kg, or even less. Some older data on the contents of BaP in smoked fish should be treated with caution, if the analytical procedures used did not guarantee unequivocal separation and identification of the individual PAH.     

Changes in benzo(a)pyrene content in fermented salami.

The benzo(a)pyrene (BaP) content of fermented salami was monitored during the technological processes of cold smoking, ripening and storage. The changes in BaP content were not so great as in products smoked with hot smoke. However, the decrease in BaP content caused by destructive action of physico-chemical environmental factors was compensated by successive dehydration of the fermented product. After recalculating the BaP content on a dry weight basis a concentration decrease was evident. Significant changes were registered during smoking and ripening while storage under different conditions caused no further effect on these changes.     

Influence of cooking on benzo(a)pyrene content in smoked sausages

The changes in benzo(a)pyrene (BaP) content of smoked sausages were monitored during 1 h cooking. During this time, the BaP content decreased from 4·80 to 1·87 μg/kg. The maximum drop in BaP content was reached in the first 20 min of cooking. Two factors affected the course of BaP changes, viz. water-holding capacity and the fat content. After excluding these factors, there was a high correlation coefficient of 0·996 between time of cooking and BaP content, which confirmed an inverse relationship between the decrease in BaP content and time of cooking.

The BaP decrease was directly proportional to the decrease of fat content during cooking, when the relatively high BaP content of 7·71 μg/kg was found in the cooked-out fat.     

Content of carcinogenic hydrocarbons in smoked foods in the German Democratic Republic and the Hungarian People's Republic

In the GDR, industrially smoked foods contain on an average 0.43 microgram Benzo(a)pyrene (BaP)/kg; products smoked according to trade rules, 0.76 microgram/kg; home-smoked products, 0.74 microgram/kg. The mean BaP content of smoked meat and sausage products in the GDR is 0.55 microgram/kg. Smoked fishes (without skin) contained on an average 1.39 microgram BaP/kg. The following average values were found in the Hungarian People's Republic: 0.6 microgram/kg (industrially smoked), 0.74 microgram/kg (home-smoked), 0.7 microgram/kg (total mean). Smoked cheese contained on an average 0.85 microgram/kg. The average BaP value of home-smoked (softwood) products of a Slovene ethnic group in the Hungarian People's Republic is 4.16 microgram/kg; the population of this region shows a considerably increased rate of stomach cancer. Apart from this particular case, the techniques used in both countries permit to obtain smoked meat and sausage products and smoked cheese with BaP contents less than 1 microgram/kg.     

Rapid determination of benzo(a)pyrene in processed meat and fish samples by second-derivative constant-energy synchronous fluorescence spectrometry

A simple, rapid and cost-effective method has been established for the determination of the quantity of benzo(a)pyrene (BaP), one of the most carcinogenic polycyclic aromatic hydrocarbons (PAHs), in roasted, smoked and charcoal grilled foods. Second-derivative constant-energy synchronous fluorescence spectrometry (DCESFS) improves the spectral resolution and selectivity of the fluorescence method. By using this method, processed meat, fish and some other food samples were analysed without resorting to complex pre-separation and purification procedures. The method was found to have a recovery of 97.7% ± 4.3%. The limit of detection (LOD) for BaP was 0.14 μg kg?1, far below the regulatory limit (1.0 μg kg?1) for BaP in food samples specified by the European Union. A certified reference material (Coconut oil, BCR?-458) was used to confirm the validity of the proposed method. The results suggest that the measurements are in a good agreement with the certified BaP concentrations (5.4% deviation). The results obtained by the proposed method for analysing BaP in food samples correlated well with those obtained by GC/MS.     

Content of strontium,lithium and calcium in selected milk products and in some marine smoked fish

The strontium, lithium and calcium contents have been determined in 87 samples of five kinds of milk-fermented products, as well as in 93 samples of ten kinds of marine smoked fish. The samples were purchased on the local market. The representative samples were dry ashed in quartz crucibles and the ash was treated with suitable amounts of conc. HCl and a few drops of conc. HNO3. The obtained sample solution was then used for the determination of Sr, Li and Ca by the flame atomic absorption spectrometry (AAS) method. Ca and Li were determined using the air-acetylene flame and Sr with nitrous oxide-acetylene flame, according to the manufacturer's recommendations. The contents of Sr in the fermented milk products ranged from 0.21 to 0.79 (mean 0.44 +/- 0.07) and in the marine smoked fish from 0.02 to 4.63 (mean 1.16 +/- 0.24) mg/kg of the edible form of both products. Li contents in the milk products ranged from 0.01 to 0.50 (mean 0.07 +/- 0.04) and in the smoked fish from 0.00 to 0.58 (mean 0.11 +/- 0.08) mg/kg. The calcium was highest in the milk products and ranged from 1,010 to 2,020.0 (mean 1,377 +/- 143) mg/kg. In the smoked fish calcium varied strongly and ranged from 40 to 1,052 (mean 303 +/- 53) mg/kg of the edible form. The calculated average ratio of strontium to calcium (mg Sr/1 g Ca) in the milk beverages and yogurts amounted 0.32 and in the smoked fish was 12 times as high and amounted 3.84. The main purpose of this work was to present Ca, Sr and Li together. This is justified because Sr and to some extent also Li are able to modulate Ca metabolism and vice versa.     

Rapid determination of benzo(a)pyrene in processed meat and fish samples by second-derivative constant-energy synchronous fluorescence spectrometry

A simple, rapid and cost-effective method has been established for the determination of the quantity of benzo(a)pyrene (BaP), one of the most carcinogenic polycyclic aromatic hydrocarbons (PAHs), in roasted, smoked and charcoal grilled foods. Second-derivative constant-energy synchronous fluorescence spectrometry (DCESFS) improves the spectral resolution and selectivity of the fluorescence method. By using this method, processed meat, fish and some other food samples were analysed without resorting to complex pre-separation and purification procedures. The method was found to have a recovery of 97.7%?±?4.3%. The limit of detection (LOD) for BaP was 0.14?µg?kg^–1, far below the regulatory limit (1.0?µg?kg^–1) for BaP in food samples specified by the European Union. A certified reference material (Coconut oil, BCR®-458) was used to confirm the validity of the proposed method. The results suggest that the measurements are in a good agreement with the certified BaP concentrations (5.4% deviation). The results obtained by the proposed method for analysing BaP in food samples correlated well with those obtained by GC/MS.     

The optimum condition for malonic dialdehyde liberation from smoked fish and curing smoke condensates

The aim of this study was to establish the conditions for malonic dialdehyde liberation from smoked fish and curing smoke condensates, as well as to determine its content in smoked fish. The specific absorption peaks of coloured solutions of malonic dialdehyde, from curing smoke condensates, with 2-thiobarbituric acid were determined. The conditions for malonic dialdehyde liberation were established, i.e. time and degree of alkaline hydrolysis of condensate, degree of distillation of acidified condensate solution, the conditions of coloured solution development, determination of extinction and method of calculation of malonic dialdehyde content in smoked fish, in individual layers of smoked mackerel fillets. The mechanism of formation of polycyclic aromatic hydrocarbone and hydrogen peroxide or hydroxyl free radicals, formed during pyrolysis of organic compounds in the presence of liberated malonic dialdehyde, was proposed.     

Polycyclic aromatic hydrocarbons (PAHs) in two Spanish traditional smoked sausage varieties: "Chorizo gallego" and "Chorizo de cebolla"

The polycyclic aromatic hydrocarbon (PAH) content in two traditional smoked sausages from Spain was determined. Results showed, that total average levels of PAHs found were higher in "Chorizo de cebolla" (101.81 vs. 98.48 μgkg(-1)). Most contents of PAHs found in both sausages were phenanthrene, naphthalene and anthracene. The maximum level for benzo[a]pyrene (BaP) of 5 μgkg(-1) in smoked meat products was not exceeded in any samples. BaP represented a 0.73% and 1.15% with respect to the total sum of the 15 PAHs that were investigated in this study for "Chorizo gallego" and "Chorizo de cebolla", respectively. Correlation statistic analysis (P < 0.01) of the contents from samples analysed, showed that BaP was a good marker for Σ15 PAHs in "Chorizo gallego" samples (R(BaP/Σ15PAHs) = 0.77; P < 0.01) and it was a good marker for 7 U.S. EPA probably carcinogenic PAHs in "Chorizo de cebolla" samples (R(BaP/7EPA) = 0.95) and in "Chorizo gallego" samples (R(BaP/7EPA) = 0.81).     

BENZO(A)PYRENE IN SMOKED MEAT PRODUCTS

SUMMARY: A procedure was established for analyzing benzo(a)pyrene (BaP) in smoked meat products, which involves extraction, solvent partition, column chromatography and spectrophotofluorometric measurement. Studies were then made as to the effect of artificial casings on the content of BaP, penetration of BaP through a meat product in smoking, possible presence of the hydrocarbon in unsmoked meats and distribution of the compound after cooking smoked meat. Bologna was used in most experiments except for the one on cooking effect, in which bacon was used. Artificial cellulose casings caused a noticeable reduction in the concentration of BaP. Regardless of whether the smoke was generated in a small-scale or in a larger-scale generator, bologna smoked in casings had much less BaP than that smoked without casings. BaP was concentrated in the outer part of bologna. In smoking with or without casings, the hydrocarbon did not penetrate farther, in most cases, than 1.4–1.6 mm from the surface of the bologna. Several unsmoked meats of beef and pork were analyzed and none seemed to have endogenous BaP, since the detected amount was similar in magnitude to that of the solvent control. More than half the amount of BaP in smoked bacon was found in the fat drippings following cooking.     

Content of strontium,lithium and calcium in selected milk products and in some marine smoked fish

The strontium, lithium and calcium contents have been determined in 87 samples of five kinds of milk‐fermented products, as well as in 93 samples of ten kinds of marine smoked fish. The samples were purchased on the local market. The representative samples were dry ashed in quartz crucibles and the ash was treated with suitable amounts of conc. HCl and a few drops of conc. HNO₃. The obtained sample solution was then used for the determination of Sr, Li and Ca by the flame atomic absorption spectrometry (AAS) method. Ca and Li were determined using the air‐acetylene flame and Sr with nitrous oxide‐acetylene flame, according to the manufacturer's recommendations. The contents of Sr in the fermented milk products ranged from 0.21 to 0.79 (mean 0.44 ± 0.07) and in the marine smoked fish from 0.02 to 4.63 (mean 1.16 ± 0.24) mg/kg of the edible form of both products. Li contents in the milk products ranged from 0.01 to 0.50 (mean 0.07 ± 0.04) and in the smoked fish from 0.00 to 0.58 (mean 0.11 ± 0.08) mg/kg. The calcium was highest in the milk products and ranged from 1 010 to 2 020.0 (mean 1 377 ± 143) mg/kg. In the smoked fish calcium varied strongly and ranged from 40 to 1 052 (mean 303 ± 53) mg/kg of the edible form. The calculated average ratio of strontium to calcium (mg Sr/1 g Ca) in the milk beverages and yogurts amounted 0.32 and in the smoked fish was 12 times as high and amounted 3.84. The main purpose of this work was to present Ca, Sr and Li together. This is justified because Sr and to some extent also Li are able to modulate Ca metabolism and vice versa.     

Benzo(a)pyrene contents of meat products

The Benzo(a)pyrene contents of 386 smoked and 18 grilled meat products were determined by application of capillary gas-chromatography-mass fragmentography using inner standards. 82 per cent of 183 black smoked hams contained appreciably more than the legal maximum amount of 1 ppb. The quantities of BaP increased very much with increase of soot accumulation on the surface. Only 15 per cent of 95 hams and only 9 per cent of 87 sausages smoked by normal methods had excessive BaP content. The amounts in excess of 1 ppb were much lower in these hams. Bratwurst grilled by use of pine-cones, spruce-cones and hard wood contained on average 28 ppb BaP. The BaP amounts of Bratwurst grilled over charcoal were without exception lower than 1 ppb.     

Levels of benzo[a]pyrene and benzo[a]anthracene in smoked “Provola” cheese from Calabria (Italy)

Levels of benzo[a]pyrene (BaP) and benzo[a]anthracene (BaA) in “Provola” cheese samples from Calabria, smoked naturally and using commercial smoke-flavouring, have been determined. A comparative study of BaP and BaA concentrations was carried out on rind, exterior zone, core and slice of these samples. Quantitative determination of BaP and BaA was ascertained by HPLC using fluorescence detection. Levels of BaP and BaA were found in all smoked “Provola” cheese samples, but higher in cheese smoked with natural methods (0.46–1.13 µg kg^?1 for BaP and 1.38–9.29 µg kg^?1 for BaA) compared to samples smoked using commercial flavouring (0.085–0.32 µg kg^?1 for BaP and 1.20–2.98 µg kg^?1 for BaA). The smoking process contributes to polycyclic aromatic hydrocarbons contamination; however, for improved food safety, the use of commercial buffered smoke is preferable to traditional smoking procedures.     

Determination of PAHs in various smoked meat products and different samples by enzyme immunoassay

An enzyme immunoassay was used to determine benzo[a ]pyrene (BaP) in smoked meat products and other samples of food and environmental origin. The method used has a detection limit (3 σ) of 0.1 μg kg⁻¹ and a coefficient of variation less than 10%. The main aim of the study was to compare the possible influence of different smoking processes and packaging material on the amount of BaP deposited on smoked meat product, mainly different sausages. The lowest amount of BaP was found when smoke produced by steam in the indirect method smoking‐chamber was used. A slightly protective effect of polyamide casing was noted. © 1999 Society of Chemical Industry     

Determination of polycyclic aromatic hydrocarbons (PAHs) in commonly consumed Nigerian smoked/grilled fish and meat

Smoking and/or grilling, when carried out with traditional methods involving direct contact with wood combustion fumes, is responsible for high contamination levels with carcinogenic polycyclic aromatic hydrocarbons (PAHs). The aim of this work was to investigate the PAH content of different smoked or grilled meat and fish products commonly consumed in Nigeria. A rapid method involving microwave-assisted saponification and simultaneous extraction followed by solid-phase extraction (SPE), high-performance liquid chromatography (HPLC) separation and spectrofluorometric detection was employed. Samples that were smoked or grilled using traditional systems, which use a wood fire, were heavily contaminated with benzo[a]pyrene (BaP) at levels ranging from 2.4 to 31.2 µg kg^?1 wet weight. Considerably lower contamination levels were found in samples smoked or grilled in the laboratory using a charcoal fire (BaP from 0.7 to 2.8 µg kg^?1 wet weight). The health risk associated with a daily consumption of 100 g of these products was also evaluated using the margin of exposure (MOE) approach. MOE values lower than 10,000 were obtained for all smoked/grilled commercial samples, indicating a potential concern for consumer health.     

Analysis of benzo[a]pyrene content from smoked food products in Korea

The content of benzo[a]pyrene (BaP) was evaluated from 100 smoked food products commonly consumed in Korean market with HPLC. Analysis method for BaP content on smoked food products was evaluated and validated. For validation, the efficiency of saponification time and solid phase extraction cartridges were evaluated. During 1–4 h of saponification, recovery of BaP was ranged from 90.17 to 98.87%. Among the 5 tested cartridges including florisil, silica gel, and alumina cartridges (acidic, basic, and neutral), the most efficient cartridge was florisil cartridge and the recovery of BaP was 98.87%. Limit of detection and limit of quantification was 0.03 and 0.09, respectively. As a result of BaP content analysis from smoked food products, the average BaP content was 0.45 μg/kg and the highest content of BaP was 2.87 μg/kg detected in smoked salmon product.     

N-NITROSOPROLINE AND N-NITROSOSARCOSINE IN ESTONIAN FOODSTUFFS

The N-nitrosoamino acids (NNA) N-nitrosoproline (NPRO) and N-nitrososarcosine (NSAR) are precursors of the carcinogenic N-nitrosamines. Methodology using gas chromatography for their determination and data on their contents in 52 food products are presented. Food products consisted of smoked meats (12), smoked (9) and boiled (11) sausage, cheese (10), fish (7) and beer (3). Results showed that NNA formed during processing, particularly in meat, where levels of NPRO were as high as 353μg/kg. The compounds accumulated in the adipose tissue and surface portion of the product. Smoking caused increased formation of NPRO, while the use of liquid smoke minimized it. NPRO in meat products in natural casings was higher than in synthetic ones, and frying of boiled sausage and hams further enchanced NPRO formation. Like meat, smoked cheese and fish showed consistently higher NNA levels than the non-smoked products. These data indicate means of reducing NNA contents in foods by modification of processing techniques .     

N-Nitrosothiazolidine and N-Nitrosothiazolidine-4-Carboxylic Acid in Smoked Meats and Fish

Various smoked meats including raw and fried bacon and both unsmoked and smoked (uncured) fish were analyzed for NThZ and NTCA. Most meat samples, bacons, and a few smoked fish contained traces of NThZ and considerably high (up to 13,700 ppb) levels of NTCA. Preliminary results indicated that raw bacons processed by old-fashioned direct smoking methods contained the highest (> 1,000 ppb) level of NTCA. Formation of NThZ from the NTCA present in smoked bacon increased with an increase in frying temperature as well as with frying time. NTCA level in the raw bacon and the cooking conditions seemed to be the most important factors involved in the formation of NThZ in the fried bacon. The reason for finding only insignificant levels of NThZ in smoked fish could not be established conclusively.     

在线净化-液相色谱法快速测定熏烤水产品中的苯并（a）芘

建立在线净化-液相色法测定熏烤水产品中的苯并(a)芘的条件及方法。使用乙酸乙酯提取后即可直接上样分析,经C8在线净化柱净化后,C18色谱柱分离,荧光检测器检测。苯并(a)芘[benzo(a)pyrene,BaP]的方法检出限为0.035 ng/mL。利用该方法对熏烤水产品中BaP进行测定,线性相关系数为0.9999,平均回收率为89.6%~99.0%,相对标准偏差为1.3%~3.1%。     

Benz(a)pyren in Fleischerzeugnissen

Zusammenfassung Im Rahmen der Lebensmittelüberwachung wurden 386 geräucherte und 18 gegrillte Fleischerzeugnisse auf ihre Gehalte an Benz(a)pyren untersucht. Die Bestimmungen erfolgten massenfragmentographisch mit einer Capillar-GC-MS-Kombination unter Verwendung innerer Standards.Von 183 schwarzgeräucherten Schinken enthielten 82% z. T. erheblich mehr als die zulässige Höchstmenge von 1 g BaP/kg. Die Mengen an BaP erhöhten sich dabei stark mit zunehmender äußerer Berußung.Bei 95 normal geräucherten Schinken wiesen nur 15% und bei 87 normal geräucherten Würsten nur 9% überhöhte BaP-Gehalte auf. Die Überschreitungen waren dabei von wesentlich geringerer Natur.Mit Kiefern- und Fichtenzapfen sowie mit Hartholz gegrillte Rostbratwürste enthielten durchschnittlich 28 g BaP/kg. Bei mit Holzkohle gegrillten Erzeugnissen lagen die BaP-Gehalte dagegen ausnahmslos unter 1 g/kg.

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Benzo(a)pyrene contents of meat products

Summary The Benzo(a)pyrene contents of 386 smoked and 18 grilled meat products were determined by application of capillary gas-chromatography-mass fragmentography using inner standards.82 per cent of 183 black smoked hams contained appreciably more than the legal maximum amount of 1 ppb. The quantities of BaP increased very much with increase of soot accumulation on the surface.Only 15 per cent of 95 hams and only 9 per cent of 87 sausages smoked by normal methods had excessive BaP content. The amounts in excess of 1 ppb were much lower in these hams.Bratwurst grilled by use of pine-cones, spruce-cones and hard wood contained on average 28 ppb BaP. The BaP amounts of Bratwurst grilled over charcoal were without exception lower than 1 ppb.