Analysis of Organochlorine and Organophosphorus Pesticide Residues in Dairy Products and Baby Foods from Egyptian Markets

The residue levels of organochlorine (OCP) and organophosphorus (OPP) in some dairy products and baby foods samples in Assiut markets Egypt were determined. The concentrations of OCP and OPP were determined in milk powder, plain yoghurt, fruit yoghurt, breakfast cereals, wheat cereal-based baby foods, rice cereal-based baby foods and vegetables and fruit-based baby foods by gas chromatography/mass spectrometry. In dairy products, the highest values of OCP and OPP were 9.346 ± 0.950 μg/kg methoxychlor in fruit yoghurt and 2.282 ± 0.400 μg/kg disulfoton in plain yoghurt, respectively. Propachlor, dieldrin (OCP), chlorpyrifos, and parathionmethyl (OPP) were not detected in any dairy product samples. Maximum amounts of methoxychlor (12.710 ± 0.700 μg/kg) and disulfoton (5.369 ± 0.510 μg/kg) were recorded in vegetables and fruit-based baby foods, and wheat cereal-based baby foods, respectively. The analysis of dairy products and baby foods showed lower pesticides values than the permissible limit set by the European Commission in all products, except methoxychlor (OCP) in vegetables and fruit-based baby foods. The results will help in a scientific assessment of the implications of pesticide residues with regards to human risks in Egypt. *Corresponding author: Al-Zahraa M Darwish, Department of Dairy Science, Faculty of Agriculture, Assiut University, Egypt, Tel: +201068925078; Fax: +20882331384; E-mail: zahraadrwish@yahoo.com Received October 11, 2016; Accepted October 24, 2016; Published October 28, 2016 Citation: Al-Zahraa MD, Soumia MD, Fathy EE (2016) Analysis of Organochlorine and Organophosphorus Pesticide Residues in Dairy Products and Baby Foods from Egyptian Markets. J Environ Anal Toxicol 6: 412. doi: 10.4172/2161-0525.1000412 Copyright: © 2016 Al-Zahraa MD, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Citation: Al-Zahraa MD, Soumia MD, Fathy EE (2016) Analysis of Organochlorine and Organophosphorus Pesticide Residues in Dairy Products and Baby Foods from Egyptian Markets. J Environ Anal Toxicol 6: 412. doi: 10.4172/2161-0525.1000412


Introduction
Pesticides protect crops from pests and are economically beneficial. However, these substances can transfer to the food and affect consumer health, especially in the food consumed by infants and children, who are a vulnerable risk group [1,2]. Dairy foods like milk and yoghurt are important nutritive foods for infant and the children because these include vitamin A, vitamin B12, riboflavin, calcium, carbohydrate, magnesium, phosphorus, protein, potassium, and zinc [3,4]. Moreover, processed foods such as cereals are particularly used as healthy food supplements for infants and young children. Infants and children are more vulnerable to the effects of pesticides as compared to adults because of high food consumption rate per kilogram of their body weight and low immunity [5][6][7][8][9][10][11]. The European Commission Directive 2006/125/EC of 5 December 2006 [12] set a limit for pesticides in cerealbased foods and baby foods for infants and young children. According to this regulation, pesticides in cereal-based foods and baby foods must not contain residues of individual pesticides at levels exceeding 10 μg/ kg (MRL). Dichlorodiphenyltrichloroethane (DDT) and its metabolites have adverse health effects such as neurodevelopment delay [13][14][15][16][17], reproductive effects [18], preterm and small-for-gestational-age babies [19][20][21], immune toxicity [7,22,23], and reduction in the mean duration of lactation (from 7 months to 3 months) [24]. Methoxychlor decreased the activity of thyroid-hormone sensitive, microsomal protein [25][26][27][28][29]. These food contaminants have dangerous effects in the early years of life. This fact has caused concern since dairy products and baby foods are an important exposure route for persistent pollutants in general. Limited data is available on the levels of OCP and OPP residues in dairy products and baby foods which constitute an important part of meal of many infants and children in Egypt. The aim of the current study was to determine the levels of OCP and OPP residues in the highly consumed types of foods by infants and young children: powder milk, plain yoghurt, fruit yoghurt, wheat cereal-based foods, rice cereal-based foods, breakfast cereals and vegetables, and fruit-based baby foods.

Sample collection
The most well-known seven foods that infants and children consumed (powder milk, plain yoghurt, fruit yoghurt, breakfast cereals, wheat cereal-based baby foods, rice cereal-based baby foods and vegetables and fruit-based baby foods), in large cities in Assiut Governorate (Assiut, Dirout, Manfalut, and Qusiya cities), were collected from June to October 2014 from the local pharmacies and markets of Assiut, Dirout, Manfalut, and Qusiya cities. Plain yoghurt, fruit yoghurt, vegetables and fruit baby food samples were identified, samples were kept frozen at -20°C prior to analysis.

Standards and reagents
In this study, pesticide standard of the OCP group included propachlor, trifluralin, hexachlorobenzene, lindane, heptachlor, alachlor, heptachlor-epoxide, p,p-DDE, dieldrin, and methoxychlor. The OPP compounds were disulfoton, parathion-methyl, malathion, chlorpyrifos, and ethion. Acetonitrile, anhydrous sodium sulfate, and sodium chloride were used. Analytical reagents were purchased from Sigma Chemical Co., Germany. [31]. Pesticides (5.0 g samples) were extracted from plain yoghurt, fruit yoghurt, and milk powder in a 50 mL disposal tube. Ethyl acetate (20 mL) and 3 g of MgSO 4 were added, followed by high-speed homogenization (1 min) and centrifugation (40000 rpm-10 min). Pesticides were extracted from breakfast cereals, wheat cereal-based baby foods, rice cereal-based baby foods vegetables and fruit-based baby foods using following steps. Five grams of sample was homogenized in a 50 mL disposal tube. Five milliliters of water was added and allowed to stand for 30 min. Acetonitrile (20 mL) was added and homogenized with a high-speed homogenizer (1 min). Four grams of MgSO 4 and 1 g of NaCl were added, and the mixture was shaken for 1 min [31].

Gas Chromatography (GC) analysis
Plain yoghurt, fruit yoghurt, powder milk, breakfast cereals, wheat cereal-based baby foods, rice cereal-based baby foods and vegetables and fruit-based baby foods samples were analyzed using gas chromatography/mass spectrometry (GC/MS). System 7890A series gas chromatograph coupled with model 5975B quadrupole mass spectrometer with a cross-linked 5% phenyl methyl siloxane capillary column (DB-5MS, 30 m × 0.25 mm id × 0.25 µm film thickness) was used. The GC operating conditions were as follows: initial temperature, 90°C (7 min hold), increased at 30°C /min to 180°C, increased at 4°C/ min to 270°C, and then increased at 30°C /min to 280°C (4 min hold). Helium at a purity of >99.999% was used as carrier gas at a flow rate of 1 mL/min. The injector port temperature was 260°C. The sample volume injected was 2 µL. The MS operating conditions were as follows: solvent delay 6 min, electron-impact (EI) mode ionization voltage 70 eV using selected ion monitoring (SIM), and dwell time of 100 ms for each ion. To improve sensitivity, the selected ions used in the SIM mode are divided into fourteen groups, guided by the individual pesticide retention times. All pesticides were identified by retention time and specific ions, and quantified by the external standard method.

Method validation
We determined the quality of the method, performed a recovery fortification of the pesticide mixtures of the dairy (plain yoghurt, fruit yoghurt, and powder milk) and other (breakfast cereals, wheat cereal-based baby foods, rice cereal-based baby foods and vegetables fruit-based baby foods) samples at final concentrations of 0.02 μg/kg and 0.10 μg/kg, respectively. We conducted 3 trials for each test and defined an acceptable result as the one with a recovery of 70~120% with an RSD ≤ 20% for both concentrations [31]. All samples were treated and analyzed using the GC/MS-SIM procedure described above. Pesticide residues were analysed in the analytical chemistry unit of the Laboratory at Assiut University, Egypt. Table 1 shows some parameters for determination of pesticide residues in the samples, using Agilent 7890 GC-MS.

Statistical analyses
Means and standard deviations (SD) of data were calculated with SPSS 9.0 for Windows (SPSS, Chicago, USA). Statistical software SPSS was used to perform one-way analysis of variance (ANOVA), and the least significant difference (LSD) test at a 95% confidence level (p<0.05).

Results and Discussion
Organochlorine pesticide residues in powder milk, plain, and fruit yoghurt Pesticide residues in dairy products have major effects on public health. Dairy products play a central role in nutrition of infants, children, and adults globally [32]. The concentration of persistent organochlorine compound residues in milk powder and yoghurt samples are presented in Table 2. Trifluralin, hexachlorobenzene (HCB), and lindane were detected in the analyzed milk powder samples. Concentrations range of trifluralin, HCB, and lindane varied from 0.254-0.354 µg/kg, 0.378-0.496 µg/kg, and 0.078-0.198 µg/kg, respectively. The average concentration of HCB (0.440 ± 0.0340 µg/kg) was higher than those of trifluralin (0.314 ± 0.030 µg/kg) and lindane (0.123 ± 0.030 µg/kg) in milk powder. Only p,p-DDE detected in plain yoghurt concentrations range was 0.259-0.309 µg/kg. These results are in agreement with those recorded by Ref. [33]. Trifluralin, lindane, heptachlor, alachlor, heptachlor-epoxide, and methoxychlor were detected in fruit yoghurt ( Table 2). Average concentration of trifluralin and Lindane were 0.157 ± 0.017 µg/kg and 2.505 ± 0.043 µg/kg in fruit yoghurt, respectively. Lindane concentrations range were higher than those reported in plain yoghurt in Ghana (0.03 µg/kg) [33]. Propachlor and dieldrin were not detected in dairy food samples. Alachlor, heptachlor-epoxide, and methoxychlor were detected only in fruit yoghurt with average values of 0.242 ± 0.043 µg/kg, 1.616 ± 0.64 µg/kg, and 9.346 ± 0.950 µg/kg, respectively. In the present study, the values of OCP in milk powder, and plain and fruit yoghurt did not exceed the permissible limit set by the European Commission, 2006 [12]. The decrease in the residue levels of these pesticides may be due to the heat-treated milk and dairy products [34]. Organochlorine pesticides can contaminate milk-producing animals through grass feeding and inhaled air and accumulate in fatrich dairy products [35].

Organophorous pesticide residues in milk powder, plain yoghurt, and fruit yoghurt
The residues of OPP pesticides in milk powder, plain yoghurt, and fruit yoghurt samples are shown in Table 3. The OPP detection includes disulfoton, malathion, and ethion, while the parathion-methyl and chlorpyrifos are not detected in all dairy products samples. Only disulfoton (0.263-0.523 µg/kg) was detected in the analyzed milk powder samples. Disulfoton and malathion were detected in plain yoghurt at concentrations range of 1.576-2.966 µg/kg and 0.279-0.489 µg/kg, respectively. OPP pesticides in fruit yoghurt were in the malathion and ethion 1.308-3.974 µg/kg and 0.644-0.801 µg/kg concentration range, respectively. Malathion was detected only in yoghurt samples, with concentration range of 0.279-0.489 µg/kg and 1.308-3.974 µg/kg in plain yogurt and fruit yogurt samples, respectively. Ethion was detected only in fruit yoghurt samples at a concentration range of 0.644-0.801 µg/kg. These results were in agreement with Ref. [36], who reported that malathion was enhanced during yoghurt processing or heat treatment [37]. Analyzed OPP contamination in 135 raw milk samples residues ranging from 5 μg/kg to 18 μg/kg. These concentrations were higher than those recorded from treated dairy products (milk powder and yoghurt), because of a decrease in OPP in milk during heat treatment or yoghurt processing. In the present study, disulfoton, malathion, and ethion levels did not exceed the permissible limit (10 μg/kg) proposed by European Commission (2006) [12] (Table 3).

Organochlorine pesticide residues in breakfast cereals, wheat cereal-based baby foods, rice cereal-based baby foods and vegetable, and fruit-based baby foods
The OCP pesticides in breakfast cereals samples were lindane 0.452 ± 0.052 µg/kg and dieldrin 1.892 ± 0.810 µg/kg. Propachlor, lindane, and heptachlor were detected at concentrations of 0.43 ± 0.042 µg/kg, 1.068 ± 0.340 µg/kg, and 2.061 ± 0.69 µg/kg, respectively, in wheat cerealbased baby foods. Lindane is used against a wide range of insects as an   Table 3: Organophorous pesticides (µg/kg)) detected in milk powder and plain and fruit yoghurts.
insecticide and fumigant, and is thus found in food products, including fruits, vegetables and milk products. HCB 0.586 ± 0.043 µg/kg was only detected in rice cereal-based baby foods. Lindane, heptachlor, and methoxychlor were found in vegetables and fruit-based baby foods with average values of 2.464 ± 0.600 µg/kg, 1.717 ± 0.780 µg/kg, and 12.710 ± 0.700 µg/kg, respectively ( Table 4). The European Commission 2003 [38] has reported maximum residue levels (MRLs) for pesticides in processed cereal-based baby foods at 10 μg/kg. In the current study, all analyzed baby foods samples showed lower pesticide residues than the permissible limit set by the European Commission [38], except methoxychlor in vegetables and fruit-based baby foods.

Organophorous pesticide residues in breakfast cereals, wheat cereal-based baby foods, rice cereal-based baby foods and vegetables and fruit-based baby foods
OPP residues were detected in baby foods, including disulfoton, malathion, and ethion with average concentration of 3.758 ± 0.780 µg/kg, 0.353 ± 0.086 µg/kg, and 2.274 ± 0.880 µg/kg, respectively, in breakfast cereals. These values were lower than the permissible limit set by the European Commission [38]. Disulfoton at mean values of 5.369 ± 0.510 µg/kg was detected in wheat cereal-based baby food. Parathionmethyl, chlorpyrifos, and ethion with mean values of 3.191 ± 0.52 µg/   kg, 0.649 ± 0.079 µg/kg, and 0.758 ± 0.072 µg/kg, respectively were found in rice cereal-based baby foods (Table 5).

Conclusions
The overall results show that OCP and OPP residues in dairy products (milk powder and plain and fruit yoghurts, baby foods (breakfast cereals, wheat and rice cereal-based baby foods and vegetables and fruit-based baby foods) in Assiut markets Egypt. The highest mean values of OCP and OPP were methoxychlor at mean concentrations of 9.346 ± 0.950 μg/kg and 2.282 ± 0.400 μg/kg in fruit yoghurt and plain yoghurt, respectively. Propachlor and dieldrin (OCP), chlorpyrifos, and parathion-methyl were absent in all analyzed dairy products. Methoxychlor (OCP) and disulfoton (OPP) showed the highest mean values of 12.710 ± 0.700 μg/kg and 5.369 ± 0.510 μg/kg in vegetables and fruit-based baby foods, and wheat cereal-based baby food, respectively. The order for the contamination in the analyzed dairy products and baby food were milk powder>fruit yoghurt>plain yoghurt and wheat cereal-based baby foods breakfast cereals>fruit yoghurt>rice cereal-based baby foods>vegetables and fruit baby foods, respectively. The results from these studies show that residues of OCP and OPP pesticides are present in dairy products, breakfast cereals, cereal-based baby food and vegetables and fruit-based baby foods. Their concentrations were lower than the acceptable maximum residue levels, except methoxychlor in vegetables and fruit-based baby foods. Although these pesticides residues occurred at very low concentrations in the samples, they may accumulate to higher levels in infant and young children upon consumption. The results of this survey demonstrate the need to establish pesticide residue monitoring programs in consumables to improve food safety and decrease health risks in consumers.