Determination of lead and cadmium contents in sausages from Iran A. Abedi a, R. Ferdousi a,, S. Eskandari b, F. Seyyedahmadian a, R. Khaksar c a National Nutrition & Food Technology Research Institute, Shahid Beheshti University of Medical Sciences, P. O. Box 19395-4741, Tehran, Iran () b Food and Drug Control Laboratories (FDCLs) – Food and Drug Laboratory Research Center (FDLRC), Ministry of Health and Medical Education, P. O. Box 11136-15911, Tehran, Iran c Department of Food Technology, Faculty of Nutrition Sciences and Food Technology, Shahid Beheshti University of Medical Sciences, P. O. Box 19395-4741, Tehran, Iran
The contents of lead and cadmium in five major brands of six types of cooked beef sausages consumed in Iran were determined by graphite furnace atomic absorption spectrometer (GFAAS) after hydrogen peroxide/nitric acid digestion. The metal contents in the samples, expressed in µg kg-1 wet weight, varied from 24. 00 to 158. 66 with an average value of 53. 54 for lead and from 2. 23 to 13. 50 with an average value of 5. 7 for cadmium.
The highest lead and cadmium concentrations were obtained from German sausage (158. 66 µg kg-1; brand B) and Hot dog (13. 50 µg kg-1; brand D), respectively. The results of this study indicate that the sausages from Iran have concentrations below the permitted levels for these toxic metals. The daily dietary intakes and the percentage contribution of the two considered metals to provisional tolerable weekly intake (PTWI) were calculated for sausages. Keywords: Lead; Cadmium; Cooked beef sausage; Dietary intake; Tehran
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Industrial evolutions, the intense use of raw materials and agricultural technology have all somehow improved our lifestyle while simultaneously polluting the natural environment. Pollution of the environment with heavy metals, which is recognized in most countries of the world, is a serious problem (Abou-Arab, 2001). Some of heavy metals such as lead and cadmium are toxic, stable and not easily biodegradable that can be very harmful even at low concentration when ingested over a long time period. The ingestion of food is known as an important way of exposure to heavy metals (Ganjavi, Ezzatpanah , Givianrad, & Shams, 2010).
Metal contamination can take place during the handling and processing of foods, from the farm to the point of consumption. Thus, besides the growth of plants in contaminated soils and the feeding of animals on feeds containing toxic metals, other factors may contribute to food contamination. Contact between food and metal, such as processing equipment, storage and packaging containers, is a significant source of metal in food (Nasreddine & Parent-Massin, 2002). Because of nutritional value and economic advantage, variety and facility of preparation, meat products are popular food source in most countries of the world.
Thus, it is necessary to enhance safety and health of meat products because of increasing consumption of these products (Demirezen & Uruc, 2006). In Iran, meat products are mainly emulsion-type cooked beef sausages that are made from meat, water or ice, oil, salt, spices, gluten and other additives under a specific technology. In recent years, much attention has been focused on the concentrations of heavy metals in fish, chicken, meat and meat products in order to check for those hazards to human health (Abou-Arab, 2001; Demirbas, 1999; Demirezen & Uruc, 2006; Emami Khansari, Ghazi-Khansari, & Abdollahi, 2004; Grujic, 2000; Oymak, Tokalıog˘lu, Yılmaz, Kartal, & Aydın, 2009; Tuzen & Soylak, 2007; Uluozlu, Tuzen, Mendil, & Soylak, 2009).
According to studies, heavy metals especially lead and cadmium can enter the body of cattle and sheep from eating forage and drinking water containing these toxic metals and accumulate in the liver, muscle and kidneys (Falandysz 1991; Niemi, Venalainen, Hirve , Hirn , & Karppanen, 1991). Furthermore, additives of the emulsion-type sausage such as oil, salt, water, spices can contain significant quantities of heavy metals (Abdel-Rahman, 1984; Brunner & Stolle, 1995; Oymak, et al., 2009; Roychowdhury, Tokunaga, & Ando, 2003; Zcan & Akbulut, 2007).
The data on the levels of toxic metals in meat products produced in Iran are very limited. The aim of this study was to determine the contents of lead and cadmium in sausages consumed in Tehran (Iran) and to estimate the intake of each metal from this source. The average consumption of sausage in Tehran was reported about 27. 6 g/day by National Nutrition and Food Technology Research Institute of Iran (NNFTRI, 2001). 2. Materials and methods
2. 1. Samples
Five brands of six types of beef sausages (German, Cocktail, Hot Dog, Lyoner, Dry and Jambon) were purchased from local supermarkets from Tehran, Iran in 2009. Samples were selected to include the major manufacturers of the sausages in Tehran. All samples were put in plastic bag/containers and transported to the laboratory on the same day and stored in -18 C until analysis.
2. 2. Reagents and standards
All reagents used were of analytical reagent grade. Distilled-deionized water was used in all experiments. Standard solutions of heavy metals, namely lead (Pb) and cadmium (Cd) were provided by Merck (Darmstadst, Germany). The standards were prepared from the individual 1000 mg/l standard, in 0. 1 N HNO3. Working standards were prepared from the previous stock solutions.
2. 3. Apparatus
All glassware was soaked overnight in 10% (v/v) nitric acid. Glassware, for the analysis of lead and cadmium was rinsed thoroughly with deionized distilled water and dried before use. A Varian Spectra AA-20 (Melbourne, Australia) atomic absorption spectrometer equipped with a GTA-96 graphite furnace atomizer and deuterium lamp as a background corrector was used in the experiments.
A Varian programmable sample dispenser was employed for injecting of the solution into the furnace. All experiments were performed using Pyrolytic-coated partitioned graphite tubes. The signals were measured as peak area. A 20µl sample was used with a 5µl of NH4H2PO4 and Mg (NO3)2 mixed matrix modifier. The operating parameters for lead and cadmium were set as recommended by the manufacturer (Table 1).
2. 4. Sample preparation and digestion
For the determination of lead and cadmium, 5 ± 0. 01 g of each samples was weighed into a 150 ml beaker and 50 ml of freshly 1: 1 (v/v) H2O2 (30%): HNO3 (65%) was added slowly in portion. Each beaker was covered with a watch glass and stored at room temperature for 48 h. The samples were heated on hot plate until the solutions were clear. Heating was continued until the volume was reduced to about 5 ml.
The solutions were then allowed to cool and sonicated for five minutes. The clear solutions were transferred into 25 ml flasks and diluted to the mark with deionized water and transferred into lidded tubes in a water-bath of 60C for 30 min. For each run, samples, spiked samples and blanks were carried through the whole procedure. The samples were analyzed in triplicate and Statistical Package for the Social Sciences (SPSS) statistical program was used to calculate standard deviations and means.
2. 5. Determination of recovery
The recoveries of the metals were determined by adding increasing amounts of lead and cadmium to samples which were then taken through the digestion procedure. The resulting solutions were analyzed for the metal concentrations. The results are reported in Tables 2. The mean recoveries for lead and cadmium were 86. 3 and 82. 5 respectively, with coefficients of variation 5. 43 and 2. 5%, respectively.
3. Results and discussion
3. 1. Lead concentrations in sausage samples
The concentrations of lead in different types of cooked beef sausages are presented in Table 3 as means with standard deviation. Lead contents in different brands of these sausages were quite variable such as brand A (25. 56-77. 13 µg kg-1), brand B (30. 93-158. 66 µg kg-1), brand C (38. 76-75. 26 µg kg-1 ), brand D (40. 33-81. 66 µg kg-1) and brand E (24. 00-46. 33 µg kg-1). The minimum and maximum lead contents of the samples were found 24. 00 µg kg-1 in German sausage (brand B) and 158. 66 µg kg-1 in Cocktail sausage (brand E), respectively.
This may be related to treatments of the products and kind or amount of spices, meat and other fillers such as gluten, ice, starch, oil and salt. The maximum lead level permitted for cooked cured meat products is 500 µg kg-1 according to the Codex Alimentarius (1994). Lead contents in all the sausage samples analyzed were lower than permitted level. The average value for lead (53. 54 µg kg-1) in this study was nearly similar to those reported in Turkey (Oymak, et al., 2009). However, this result was lower than those detected in Chile (Mun˜oz, et al., 2005), the Republic of Croatia (Sapunar-Postruznik, Bazuli, Kubal, & Balintb, 1996) and Turkey (Demirezen & Uruc, 2006).
In the island of Tenerife (Spain), González-Weller, Karlsson, Caballero, Hernández, Gutiérrez, Gonzlez-Iglesias, et al.,(2006) reported 3. 16, 9. 12, 6. 72 and 4. 89 µg kg-1 lead in chicken, turkey, beef and pork meat product, respectively, which are lower than values reported here. The entrance of lead at levels > 0. 5–0. 8 µg/ml into blood causes various abnormalities. Lead accumulates in the skeleton, especially in bone marrow. It is a neurotoxin and causes behavioral abnormalities, retarding intelligence and mental development. It interferes in the metabolism of calcium and vitamin D and affects hemoglobin formation and causes anemia (Memon, Hasany, Bhanger, & Khuhawar, 2005).
3. 2. Cadmium concentrations in sausage samples
Cadmium contents in the sausage samples studied are given in Table 4. The concentrations of cadmium in the sausages with different brands were found to be in the range of 3. 23-5. 76 µg kg-1 for brand A, 2. 90-11. 23 µg kg-1 for brand B, 2. 33-8. 96 µg kg-1 for brand C, 5. 00-13. 50 µg kg-1 for brand D and 2. 23-7. 63 µg kg-1 for brand E (mean: 5. 70 µg kg-1) . The highest average cadmium was obtained from Hot dog (13. 50 µg kg-1; brand D) while the lowest values was observed in German sausage (2. 23 µg kg-1; brand E). Cadmium concentrations obtained from the analyses of all the sausage samples were lower than the limits established by European Communities, 50 µg kg-1 (Commission of the European Communities, 2001).
The mean concentration of cadmium (5. 70 µg kg-1 ) in present study was approximately similar to those detected in Chile (Mun˜oz, et al., 2005), Tenerife, Spain (González-Weller, et al., 2006) and Turkey (Oymak, et al., 2009) and higher than in Greece (Karavoltsos, Sakellari, Dimopoulos, Dasenakis, & Scoullos, 2002) and lower than in the Canary Islands, Spain (Rubio, et al., 2006), the Republic of Croatia (Sapunar-Postruznik, et al., 1996), Turkey (Demirezen & Uruc, 2006) and the Banja Luka, Bosnia (Grujic, 2000). Cadmium may accumulate in the human body and may induce kidney dysfunction, skeletal damage and reproductive deficiencies (Commission of the European Communities, 2001).
The maximum tolerable level of Cd in the kidney, in order to avoid abnormal kidney function, is 50 mg/g wet weight (Satarug, Haswell-Elkins, & Moore, 2000). Hecht (1983) declared that cadmium concentrations in meat increase with the age of the animal and depends on the concentrations of Cd in the feed. Generally, the level of trace elements in meat and meat products depends on factors such as environmental conditions, type of pasture and genetic characteristics of organisms. Furthermore, technological treatments are important for levels of trace elements in meat products (Demirezen & Uruc, 2006).
3. 3. Estimation of lead and cadmium intakes from sausages
The dietary intake of each toxic metal is calculated by multiplying the concentration of the metal in a particular food category by the mean weight of that group consumed in the daily diet of an average person (Urieta, Jalo´n, & Eguileor, 1996). Considering the amount of sausage consumption in Tehran (27. 6 g/day) and the mean concentrations of lead (53. 54 µg kg-1) and cadmium (5. 70 µg kg-1) in these products, the dietary intakes of lead and cadmium were calculated as 1. 47 and 0. 16 µg/day (10. 29 and 1. 12 µg/week), respectively. The average consumption of the sausages was assessed on the basis of data obtained through monitoring of the per capita consumption of foodstuffs in Tehran, Iran (NNFTRI, 2001).
The dietary exposures of lead and cadmium through meat products in literature have been reported as 3. 6 and 0. 14 µg/day, in Santiago, Chile (Mun˜oz, et al., 2005) and 3. 85 and 0. 28 µg/day, in the Republic of Croatia (Sapunar-Postruznik, et al., 1996), respectively. Also, Rubio et al., (2006) reported 0. 21 µg/day cadmium intake via cold meat and sausages in the Canary Islands.
To evaluate the health risk of the estimated dietary exposure, it is compared with the provisional tolerable weekly intake (PTWI) recommended by the Joint FAO/WHO Expert Committee for Food Additives (JECFA) for each of the toxins: 25 µg Pb/kg body weight; 7 µg Cd/kg body weight (equivalent to 243 µg Pb/day and 68 µg Cd/day for an adult of 68 kg) (WHO, 1993). If we express the dietary intake of lead and cadmium in a percentage of PTWI, the intake of lead and cadmium through sausages results in 0. 6% and 0. 23% of PTWI, respectively.
The levels of lead and cadmium in different types of sausages with several major brands marketed in Iran were determined by a suitable and sensitive method (GFAAS). The results obtained in the present study showed that lead and cadmium levels in all the sausages analyzed were acceptable for human consumption at toxic levels. The level may be reduced by more careful handling practices and processing of raw materials.
Also, a better selection of the raw material, including an analysis for toxic trace elements prior to processing, could surely improve the situation. The estimated intakes of lead and cadmium from weekly consumption of the samples indicated no risk since they are lower than the permissible tolerable weekly intakes for these elements. However, lead and cadmium may enter the human body through other foods containing these toxic metals. It is recommended to carry out a regular control of lead and cadmium concentrations in meat products and other foods in Iranian supermarkets.
All authors acknowledge the National Nutrition and Food Technology Research Institute of Iran (NNFTRI) for its financial support.