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Alternaria mycotoxins are the secondary metabolites for which the regulations, as well as the standardization, are yet going to be established by the European Commission and the European Committee for Standardization. This paper describes the possibility to apply a "dilute-and-shoot" method for the determination of tentoxin, alternariol and alternariol monomethyl ether in wheat. The used chromatographic method was liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). The strategy involves extraction the samples with the acetonitrile and water mixture (84/16, v/v), followed by the vortexing, centrifugation and filtration before the injection into the LC-MS/MS system. The recovery was assessed by analysis of spiked samples with a mixture of standard solutions of all three mycotoxins at two spiking levels (0.02 and 0.1 mg kg-1) in six replicates. The obtained average recoveries and precisions (expressed as the RSDr, %) for "dilute-and-shoot" method were 76.3% (RSDr of 6.47%) for alternariol, 105.2% (RSDr of 2.16%) for tentoxin, and 86.0% (RSDr of 3.91%) for alternariol monomethyl ether. All the obtained validation data were in accordance with the Commission Decision 2002/657/EC and Commission Regulation (EC) No 401/2006. The main advantages of the present method are the simple and easy sample preparation, along with the high-sensitivity detection.

The performance of the QuEChERS extraction followed by the LC-MS/ MS analytical method was evaluated in terms of Alternaria mycotoxins recovery from the wheat. The alternariol (AOH), tentoxin (TEN) and alternariol monomethyl ether (AME) were analyzed using the ESI+ (electrospray positive ionization) by multiple reactions mon­itoring mode (MRM). In order to determine the recovery, the blank wheat samples were spiked at two spiking levels (0.01 and 0.1 mg/kg) in six replicates. The obtained average recoveries and precisions (expressed as the RSDr, %) were as follows: 107.6% (RSDr of 6.84%) for alternariol, 108.0% (RSDr of 6.78%) for tentoxin and 110.1% (RSDr of 6.50%) for alternariol monomethyl ether. The results of this study were in accordance with the Commission Decision 2002/657/EC and Commission Regulation (EC) No 401/2006.

The purpose of this study is to assess the repellent activity of lemongrass (Cymbopogon citratus) essential oil (EO), grown in Serbia under greenhouse conditions, against four prevalent stored product pests: Plodia interpunctella (larvae), Sitophilus oryzae, Acanthoscelides obtectus and Tribolium castaneum (adults). The lemongrass EO repellency was tested using filter paper in Petri dishes and a Y-tube olfactometer. According to the repellency index (RI), the lemongrass EO repellency was divided into 5 classes. Prior to biotesting, the chemical characterization of lemongrass EO was performed and the following main compounds were detected: myrcene (31.0%), geranial (30.0%), and neral (23.6%). The C. citratus EO considered was found to exhibit the Class III repellent activity against P. interpunctella larvae only at the highest concentration (namely 0.5%). This is the very first report on the C. citratus EO repellent activity against this pest. The lemongrass EO examined showed strong repellency (Class IV) against S. oryzae (0.2% and 0.5% of EO), A. obtectus (0.1% and 0.2%), and T. castaneum (0.05-0.1%). Moreover, higher lemongrass EO concentrations (0.5%) were found to exhibit extreme repellency (Class V) against A. obtectus and T. castaneum. The results obtained were confirmed in the bioassays performed, indicating the great potential of lemongrass EO as a bio-repellent when applied in higher concentrations to all the insects considered, regardless of the exposure period.

The interest in tropane alkaloids as food contaminants has been increasing. The tropane alkaloids are plant toxins that mainly occur in Atropa, Datura and Hyoscyamus sp belonging to the Solanaceae family. A sensitive and selective LC-MS/MS method was applied for the analysis of atropine and scopolamine in the mint tea samples from the Serbian market. Tea, which has beneficial properties thanks to the phenolic compounds, can be accidentally contaminated by many weed seeds which contain the tropane alkaloids during the harvest. Only the tropane alkaloids present in the tea bags before the tea making were analysed. Atropine and scopolamine were detected in 30% of the analysed samples in the concentration above the limit of quantification.

The interest in tropane alkaloids (TA) as food contaminants is increasing. A sensitive and selective LC-MS/MS method was applied for the analysis of corn puff samples from the Serbian market. Only atropine was quantified in 22% of the samples. In case of scopolamine, although not quantified, it was detected in 22% of the samples. Whether the acute reference dose (ARfD) could be exceeded was checked on a case-by-case basis for the individual products under assessment. Due to their low body weight and relatively high snack consumption, preschool children were at the highest risk of TA exposure. Assuming that the average consumption is 50 g of corn puffs per day, the sample with the highest concentration of TAs (2.05 μg/kg, 1.58 μg/kg of atropine) could contribute with 32.0% to the ARfD, of which 24.7% owing to atropine. If the same amount of corn puffs is consumed by older age classes, corresponding exposure contributions to the ARfD would progressively decline, down to 8.4% for adult population. The study revealed no health risk from TAs exposure through the consumption of the corn puffs in Serbian population.

Studies of adsorption and desorption of pesticides by soils are important for understanding and predicting their fate and transmission in the environment. Considering the agricultural and environmental relevance of clomazone, its sorption–desorption behaviour was studied in two widespread Serbian agricultural soil types named Regosol and Chernozem. Both phenomena are well-described by the Freundlich equation, which shows that clomazone is generally sorbed more to organic matter than to the mineral soil fractions. Chernozem, a soil containing more of both organic matter and clay, was found to bind more, and desorb less herbicide, than Regosol. Higher desorption hysteresis obtained for Chernozem could be attributed to its larger number of high- -energy sorption sites, compared to Regosol. In both soils, the hysteresis effect increases with the rise of initial clomazone concentration in the soil-water system, while the percentage of desorbed amount during successive desorption cycles decreases. The presented adsorption–desorption study shows that soil composition plays an important role in clomazone behaviour and fate in the environment, and a significantly reduced probability of contamination of both the deeper soil layers and groundwater may be expected when this herbicide is found in humus-rich soils

Bisphenol A is a monomer used primarily in the production of polycarbonate plastics and epoxy resins. Polycarbonate plastic is used in a wide variety of digital media products, electrical and electronic equipment, sport safety equipment, reusable food and drink containers, etc. Epoxy resins are used in engineering applications, paints and adhesives and also in a variety of protective coatings in metal cans for foods, bottle tops and water supply pipes. The content of BPA was evaluated in 16 samples (6 baby bottles and 10 drinking containers - can) collected during 2018/2019, of which three baby bottles and 8 cans were collected in 2018, while three baby bottles and 2 cans in 2019. A simple HPLC-FLD analytical method was validated for the quantitation of BPA from baby feeding bottles and cans. The separation was performed on a C18 column. Good linearity was obtained over the concentration range of 0.3-6.0 μg/mL with the regression coefficient (R2) of 0.9998. The limit of detection (LOD) and limit of quantification (LOQ) were 0.01 and 0.03 μg/mL, respectively. The repeatability of the method (%RSD) was between 4 and 6%, while the recovery ranged from 104.3 to 109.7%. The extraction of BPA was done in accordance with SRPS EN 13130-1:2008. The methods were applied to determine BPA release from baby bottles, performing repeated procedures according to EU and national regulations (SRPS CEN/TS 13130-13 (2008)). The conformity was evaluated according to National and EU requirements. The results show that Bisphenol-A was not detectable in any of the analysed samples. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. TR31038]

The undemanding LC-MS/MS method was developed for the synchronized analysis of atropine and scopolamine in maize crop. The dSPE was carried out with 1% acetic acid in acetonitrile/water and a mixture of magnesium sulphate, sodium chloride and sodium citrate. The analytes were separated on a Zorbax XDB C18 column using methanol/water as the mobile phase in gradient mode. The detection was done using a tandem masss spectrometry (MS/MS) in the positive ESI. The tropane alkaloids exhibited excellent linearity in the range of 2-20 µg/kg with the LOQ of 5 µg/kg for maize. The extraction recoveries of atropine and scopolamine were 65.7 and 85.5% with the intraday RSDr 10.25 and 4.29%, respectively. The validated method was appled to real maze samples. One sample contained 18.8 µg/kg of atropine and 6.3 µg/kg of scopolamine.

During 2018 a total of 42 sour cherry samples were collected and analysed for pesticide residues by LCMS/MS with the carbofuran–D3 and acetamiprid-D3 as internal standards. The study showed that 42.86% of the analysed samples contained pesticide residues. In percentage terms, it seems to be high, but most of the detections were below the recommended MRL values, which is encouraging. The analysis indicated that three of the analysed sour cherry samples (7.14%) contained pesticide residues above the MRLs (propiconazole, methomyl, dimethoate and prochloraz). In spite of the low concentrations, ten samples contained multiple detections, i.e. 55.56% of the analysed samples contained more than one pesticide residue.

The objective of this research was to investigate the influence of osmotic dehydration as a pre-treatment to the air drying of strawberries. Fresh, untreated strawberries were sliced and dried in a sucrose solution at a temperature of 50 oC and concentrations of 50 and 65 oBx. After osmotic dehydration, the slices were dried in a thin layer at air temperatures of 60, 70 and 80 oC, and an air velocity of 1 m/s. After osmotic dehydration, the moister content and solid gain at a sucrose solution concentration of 55 oBx were 3.44 gw/gdm and 0.062 gdm/g, respectively. However, the moister content and solid gain in at a sucrose solution concentration of 65 oBx were 4.08 gw/gdm and 0.0944 gdm/g (65 oBx), respectively. The effective moisture diffusivity of air drying varied from 1.57 x 10-9 to 4.43 x 10-10 m/s2, increasing with an increase in air temperatures and decreasing with an increase in pretreatment source concentrations. Lower air temperatures exert a positive influence on the rehydration time. A shorter air drying process positively affects the total changes in colour. The impact of pretreatment on colour changes in strawberries was not recorded after drying.

The aim of this paper is to present the influence of convective drying of organic pear pulp and adding ascorbic acid on changes in color, the difference in vitamin C content and also show the kinetics of convective drying. It was a two-factor experiment. The first factor was the air temperature needed for drying, between 45 °C and 65 °C, with a constant speed of drying air of 1.5 m/s; the second factor of the experiment was the adding of ascorbic acid to the pear pulp in the amount of 1 % and 2 % of the full mass of the prepared pulp. The lowest change in color was achieved by adding ascorbic acid in the amount of 2 % of the full mass of the pulp and drying air temperature of 45°C (ΔE= 23.981). The highest change was accomplished at the air temperature of 65 °C and by adding ascorbic acid in the amount of 1% (ΔE= 30.039). With samples where ascorbic acid was added reduction of vitamin C was over 99 % with all samples. By examining the kinetics of convective drying based on statistical indicators R, X2, RMSE, models Page and Logarithmic are the best in representing convective drying of pear pulp at air temperatures of od 65 °C and 45 °C respectively.

This study had two major objectives: 1) to investigate the influence of a seven-month storage period on maize contamination with aflatoxins (AFs) and 2) to examine the distribution of total count of fungi (TCF), A. flavus and aflatoxin B1 (AFB1) in the stored maize kernels. In the first part of this survey, 700 maize samples were collected in the period from October 2012 to April 2013. Presence of AFs was detected in 72% of maize, before entering the silos. The survey results indicated that the percentage of contaminated maize samples as well as the distribution of determined AFs concentrations changed during the storage period of seven months. By the prolongation of storage period, the percentage of non-contaminated maize samples decreased from 28% to 16%, while the percentage of contaminated samples in the concentration range 20-50 µg/kg increased from 18% to 25%. In the second part of this study, 32 maize samples from four different silos were analysed. The results showed that TCF, A. flavus and AFB1 were unevenly distributed. According to Duncan's multiple range test, in each silo, statistically significant differences (p

Plodia interpunctella (Hübner), the Indian meal moth (IMM), is a major lepidopteran storage pest worldwide. IMM larvae can be found in high abundance in stored maize and cause huge losses in seed germination and seed viability. This work aimed to assess the susceptibility of six maize hybrids (NS 6140, NS 640, NS 1090, NS 444 - dent type, NS 620k - pop-corn type, Red-aleurone maize - maize with an altered aleuron color) to IMM attack and suitability for pest's development. Standard laboratory diet (SLD) was used as a positive control. Under laboratory conditions, the following IMM life history parameters were monitored: larval mortality, mean developmental duration (egg to adult), adult emergence, adult lifespan and female fecundity. Kernel susceptibility was determined based on the Susceptibility Index (SI). The highest mortality of IMM larvae was on NS 620k (35.25%) compared to the other maize hybrids (11.2-19.5%). The highest number of emerged adults was on Red-aleurone maize (17.5), and the lowest on NS 620k (4.0). The longest lifespan was recorded for moths reared on NS 6140 and NS 640 (8.5 and 8.7 days, respectively). The highest female fecundity was on SLD (115.8 eggs), on Red-aleurone maize (44.3 eggs), while females reared on NS 620k laid the lowest number of eggs (22.8 eggs). Moths reared on NS 620k had the shortest body sizes (0.9 cm), which indicated reduced moths fitness. SI showed that Redaleurone maize (SI=7.79) was the most susceptible to IMM attack, while NS 620k (SI=3.08) was the least susceptible.

Aflatoxins (AFs), fumonisins (FUMs), zearalenone (ZEA) and deoxynivalenol (DON) have been recognized as major contaminants of maize. Therefore, the presence of AFs, ZEA, DON and FUMs was examined in a total of 100 maize samples from the Autonomous Province of Vojvodina. Sample analyses were performed using the Enzyme Linked Immunosorbent Assay method. The results obtained indicate that 74 % of the maize samples were contaminated with FUMs (540.1-5076 μg/kg), followed by 52 % contaminated with DON (275.2-882.1 μg/kg), 15 % contaminated with ZEA (35.6-183.5 μg/kg) and 5 % contaminated with AFs (2.28-4.31 μg/kg). Although 78 % of the samples were contaminated with at least one mycotoxin, the concentration of FUMs exceed the maximum level (ML) proscribed by the Serbian regulations only in 4 % of the samples. Furthermore, the detected concentrations of AFs, ZEA and DON were in accordance with national regulations. This study is the first research of its kind on the presence of AFs, ZEA, DON and FUMs in maize harvested in the APV in 2016.

A reliable and easy method has been used for the multiple mycotoxins determination of AFs, DON, ZEA and FBs in maize samples. Liquid chromatography cou­pled mass spectrometry (LC-MS/MS) was used. Mycotoxins have been extracted from maize using a QuEChERS-based extraction procedure. All validation parameters were in accordance with Reg. (EC) No 401/2006. The analyses of eight maize seed samples showed the AFs, DON, ZEA and FBs contamination with the values below the state limit standards.

The analysis of citrinin is challenging because it needs to be detected in low concentrations in complex sample matrices. Before citrinin quantification, the data acquisition of LC-MS/MS must be performed, which includes the determination of ion monitoring reaction (SRM), finding fragmentation energies (Frag.) and collision cell energies (CE) for which the response of citrinin will be the highest for the given conditions. The best response of citrinin is obtained for Frag. of 66 V and CE of 17 and 29 V. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. TR31018]

The aim of this paper was to investigate deoxynivalenol (DON) occurrence in maize samples originating from two harvest seasons in Serbia. The key differences between harvest seasons were weather conditions, specifically the humidity. The samples were analyzed using high performance liquid chromatography with DAD detection, after clean-up on SPE columns. In samples from 2014, DON was found in 82 (100.0%) samples with the average content of 2.517 mg/kg (ranged from 0.368 to 11.343 mg/kg). Two samples exceeded maximum level permitted by EU regulations. However, analyzing larger number of samples (163) from 2015 harvest season, DON was present in 51 (31.3%) samples in significantly lower concentrations (average of 0.662 mg/kg, ranged from 0.106 to 2.628 mg/kg). None of the samples from 2015 exceeded maximum level permitted by EU regulations. The data on DON presence in Serbian maize were in relation to the different weather conditions that prevailed during the two harvest seasons. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. 172042]

The paper deals with the screening analyses of apple samples with the suspicion of having been treated beyond regular protection. The extraction of pesticides was carried out by the QuEChERS method. By GC-MSD and based on DRS analyses the presence of phosalone (tR=29.73 min) and dimethoate (tR=12.78 min) was detected. According to the National Regulation MRL value for the dimethoate in apples is 0.02 mg/kg and 0.01 mg/kg for phosalone. From the above facts it can be concluded that the dimethoate value was five times higher than allowed while that of phosalone was even ten times more.

Soluble free phenolics (SP), PVPP-bound tannins (PVPP-P), flavonoids (TF) and proanthocyanidins (PA) content, as well as the DPPH-radical scavenging capability of the whole grain of 17 different Triticum spp. accessions were analyzed. The content of SP ranged from 976 to 2927 μg CE/g, while PVPP-P ranged from 335 to 1412 μg CE/g and TF from 0.16 to 1.12 μg RE/g of dry whole grain. The presence of PA in the whole grains has not been established. The values for DPPH-radical scavenging activity were rather moderate, under 40 % of neutralized radicals. A positive correlation between DPPH-activity and analyzed phenolics was recorded in twelve of seventeen genotypes (r=0.73-0.99). Trans-cinnamic acid was the major compound among phenolic acids and quercetin among flavonoids found in wheat varieties. The data obtained should enable the selection of the accessions rich in biologically active compounds that could further be processed into functional food with possible health benefits associated with higher antioxidant properties. [Projekat Ministarstva nauke Republike Srbije, br. TR-31066]

Aldrin, endrin and dieldrin are highly toxic and persistent cyclodiene-type organochlorine pesticides. Although these compounds have been banned over the last few decades in many countries, they can still be found in the environment, especially in the agricultural soil. In order to determine the residue levels of cyclodiene-type organochlorine pesticides in soils of Vojvodina Province, and to obtain detailed information on their spatial distribution, 1370 soil samples under different land uses were collected from Vojvodina Province and analyzed for the presence of aldrin, dieldrin and endrin. The residues of those pesticides were detectedin the soils of Vojvodina in measurable concentrations and dieldrin was the most dominant compound in the soil. However, the concentrations of analysed cyclodiene-type organochlorine pesticides in the most soil samples from Vojvodina province were lower than Dutch target valuesfor soil quality.Soil organic matter and clay content were found to be positively associated with aldrin content while clay content was found to be negatively associated with endrin. [Projekat Ministarstva nauke Republike Srbije, br. TR 31072: Status, trends and possibilities to increase the fertility of agricultural land in the Vojvodina Province]

A method is described for simultaneous determination of five herbicides (metribuzin, acetochlor, clomazone, oxyfluorfen and dimethenamid) belonging to different pesticides groups in soil samples. Developed headspace solid phase microextraction method (HS-SPME) in combination with liquid-solid sample preparation (LS) was optimized and applied in the analysis of some agricultural samples. Optimization of microextraction conditions, such as temperature, extraction time and sodium chloride (NaCl) content was perfor-med using 100 μm polydimethyl-siloxane (PDMS) fiber. The extraction effi-ciencies of methanol, methanol:acetone=1:1 and methanol:acetone:hexane= =2:2:1 and the optimum number of extraction steps during the sample prepa-ration, were tested, as well. Gas chromatography-mass spectrometry (GC-MS) was used for detection and quantification, obtaining relative standard deviation (RSD) below 13%, and recovery values higher than 83% for multiple analyses of soil samples fortified at 30 μg kg-1 of each herbicide. Limits of detection (LOD) were less than 1.2 μg kg-1 for all the studied herbicides. [Projekat Ministarstva nauke Republike Srbije, br. TR31043 i br. III43005]

Extensive use of synthetic insecticides, herbicides and other pesticides has negative effects on the environment and on human and animal health. Therefore scientists are turning towards natural pesticides such as active components of plant extracts. Effect of two concentrations (0.1% and 0.2%) of Satureja montana L. aqueous extract on lipid peroxidation process, as well as the activity of the antioxidant enzymes (SOD, GPX, PPX and CAT) in leaves and roots of pepper and black nightshade seedlings were examined 24, 72 and 120h after the treatment. Our results showed that higher concentration of S. montana aqueous extract induced lipid peroxidation in black nightshade roots. Furthermore, significant increases of pyrogallol and guaiacol peroxidase were detected in black nightshade leaves treated with 0.2% S. montana aqueous extract. The second aim was to evaluate effectiveness of aqueous extract as contact toxicant against whitefly. It was observed that aqueous extract with concentration of 0.2% showed toxic effect with 68.33% mortality after 96h.

Aflatoxins (AFs), one of the most toxic and the strongest natural carcinogens can be found in a variety of food commodities, including cereals. For that purpose, the aim of this study was to investigate occurrence of AFs (AFB1, AFG1, AFB2 and AFG2) in 130 cereal samples. AFs content was determined by direct competitive Enzyme Linked Immunosorbent Assay (ELISA) method. Samples with AFs content higher than 1 μg/kg were analyzed again with confirmatory High Performance Liquid Chromatography with fluorescence detection (HPLC-FLD). Analyses showed that none of the analyzed wheat (30), barley (20), oats (20) and rye (20) samples was contaminated with AFs. On the other hand, among 40 analyzed maize samples 24 of them (60%) were contaminated in the following way: 6 (25%) samples had AFs concentration between 1 and 10 μg/kg, 14 (58%) samples between 10 and 50 μg/kg and 4 (17%) between 50 and 70.3 μg/kg. The most predominant aflatoxin was AFB1 which was detected in all contaminated maize samples. AFG1, AFB2 and AFG2 were found in 12, 5 and 1 sample, respectively. This study represents the first investigation of the occurrence of AFs in five different cereals from Serbia.

Mycotoxins are highly toxic compounds produced by molds that commonly occur in cereal grains. These toxins can have adverse effects on human and animal health. Mycotoxin decontamination procedures can be divided into three different groups: chemical, biological and physical. Procedures from the first two groups are often regarded as unacceptable for lowering the mycotoxin level. A laboratory brush was developed for the purpose of physical cleaning of corn kernel. Three samples of commercially available corn kernels were subjected to the brushing procedure in order for the experimental study to be conducted. The mass of 100g of corn kernels was placed on motionless screen of the brush. A rotating part of the experimental device, the polypropylene bristle brush was set to high­er speed (higher than 800 rpm). During the corn brushing, dust and broken kernels were brushed out through the motionless screen. Corn samples were taken before and after the brushing procedure and they were analyzed for aflatoxin concentration by HPLC-UV RED. By comparing the control and brushed samples, it can be noticed that removal of fines caused the reduction in the level of mycotoxins in all three brushed samples.

A total of 45 samples of wheat from three different locations in Vojvodina were analyzed for the presence of zearalenone. Analytical methods based on clean-up by solid-phase extraction (SPE) columns and detection by liquid chromatography were used after validation. Limit of detection for ZEA in wheat was 18.6 μg/kg and the limit of quantification was 56.5 μg/kg. Recovery values ranged between 86% and 97%. The occurrence of ZEA in wheat was rather high with 53.3% of positive samples with the average value of 330 μg/kg. Incidences were found from 68 μg/kg to 1079 μg/kg. Contamination levels were above the established maximum limit for unprocessed cereals, other than maize, in as many as seventeen samples. These results were compared to the results of investigation of deoxynivalenol and fumonisin content, established in our previous work on the same samples. The results obtained were also compared to those of the neighboring countries where the relevant data existed and to the data of previous studies in our country. [Projekat Ministarstva nauke Republike Srbije, br. TR31081]

A reliable and easy method has been developed for the determination of aflatoxins B1 and G2 in maize samples. High performance liquid chromatography coupled with FLD (HPLC-FLD) with photochemical derivatization was used. Mycotoxins were extracted from maize using a QuEChERS-based extraction procedure. The optimized analytical conditions were evaluated in terms of recoveries, reproducibility, LOD, LOQ and linearity for aflatoxin B1 and aflatoxin G1 in maize. Extraction, chromatographic and detection conditions were optimized in order to increase sample sensitivity. The linearity was analyzed in the range of 0.4-20 μg/kg and the correlation coefficients (R2) were higher than 0.99 for aflatoxins B1 and G1. Blank samples were spiked at 1.0, 2.0 and 4.0 μg/kg, and the average recovery for aflatoxin G1 was 96.96±1.72% and for aflatoxin B1 it was 86.80±1.24%. RSDs were lower than 25% for both mycotoxins. LOD for both aflatoxins was 0.5 μg/kg and LOQ was 1.0 μg/kg, respectively.

A simple HPLC determination method of maleic hydrazide residues in onions was introduced. The homogenized onion samples were extracted with methanol. The crude ex- tract was purified on SPE SampliQ SCX column. The maleic hydrazide was analyzed by HPLC with UV detection of 313 nm. The HPLC separation was performed on SynChropak Q column with 0.25 M phosphate buffer as the mobile phase. The recoveries of maleic hydrazide from the spiked onions with 1.5, 2.0, 3.0, 5.0, 7.0 and 10.0 mg ml-1, ranged from 89-103%. The detection limit of maleic hydrazide was 0.4 mg ml-1, and the quantification limit was 1.25 mg ml-1. The linearity coefficient was 0.9998. Such an optimized method was applied to the determination of residue content of maleic hydrazide in onions, treated with Royal MH-30 in the amount of 8.0 and 12.0 l ha-1. The samples were analysed after 8, 16 and 25 days from the moment of spraying. The obtained values of maleic hydrazide residues were below the maximum tolerable amount in the Republic of Serbia (10 mg kg-1), as well as the amount regulated by the EU (15 mg kg-1). .

This paper deals with the contamination of our environment with thousands of both natural and man-made chemicals which affect the endocrine system of humans and animals. These so-called endocrine disrupting chemicals (EDCs) are thought to mimic or block the action of hormones and therefore disrupt sexual development in utero. EDCs are organochlorine pesticides, dioxin compounds, polychlorinated biphenyls, alkylpolyethoxylates, plastic additives and phytoestrogens (occurring naturally in foods: isoflavones coumenestans and zearalenone). The structure of zearalenone is similar to the structure of estrogens and it enables binding to the estrogenic receptors. DNA laddering on gel electrophoresis was present 12 h after dosing thus indicating a conclusion that there was apoptosis. Apoptosis is the principal mechanism contributing to germ cell depletion and testicular atrophy following zearalenone exposure.

Ochratoxin A is cancerogenic, teratogenetic, immunotoxic and nephrotoxic The mentioned order stresses the importance of this toxin concerning its harm to human health. The harmful effects of ochratoxin A include the effects at molecular level, such as DNA fragmentation, protein synthesis inhibition gluconeogenesis, lipid peroxidation, disorder of oxydative phosphorization in mitochondria, inhibition of blood coagulation and apoptosis. The presence of ochratoxin A in a great number of food samples, both of plant and animal origin, is the obvious risk to human health, which is confirmed by the high incidence of this toxin in samples of human serum and milk. It could be stated, with certainty, that the above - mentioned facts are the reason for which the EU has paid great attention to this mycotoxin in recent years. This paper deals with the results of the analysis of the animal feed component samples for the period 2000-2003 concerning the ochratoxin A content. The analysed feed components were taken from the farms with significant health problems of animals (not monitoring). The samples were analysed by chromatography on a thin layer and with a limited detection method for ochratoxin A of 40 ppb. The analysis was carried out on 108 maize samples, 11 barley samples, 21 wheat samples, 42 sunflower pellets samples and 47 soybean pellets samples (Table 1). The samples of sunflower pellets were contaminated in the greatest percentage, which indicates the inadequate storage of this feed component.