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Given that the presence of fumonisin as a potentially carcinogenic com­pound in the aqueous medium was confirmed, it is very important to find a method for its effective removal. In this study, the degradation efficiency of fumonisins in aqueous media was investigated by direct and indirect photolysis under simulated solar irradiation (SSI). The initial pH value had a significant effect on the kinetics of fumonisin B1 (FB1) degrada­tion, with the highest efficacy observed at pH 4.0 (88%), and the lowest at pH 10.0 (21%) during the 180 min of irradiation. Under these experimental conditions, FB1 photolysis in the first degradation period follows pseudo-first-order kinetics. In comparison to direct photolysis, indirect photolysis using H2O2 had an inhibitory effect on the degradation of FB1. Namely, 24% of FB1 was degraded during 180 min of irradiation at pH 8.0, while 74% was degraded by direct photolysis for the same period of time. In the case of the application of indirect photolysis using S2O82- at pH 4.0, the degradation efficiency of FB1 (91%) was similar as in the case of direct photolysis (88%), at the same pH, as well as for the same period of time. Considering the degradation efficiency, it was concluded that in both cases only direct photolysis was performed, probably because SSI does not contain suitable wave­lengths for sulfate radical (SO4•-) formation. Based on this, we can conclude that direct photolysis at pH 4.0 is practically the most suitable treatment for FB1 removal under SSI.

The health safety of honey includes the correctness in terms of the presence of different contaminants, which also implies the antibiotic residue. The presence of antibiotics in honey is prohibited, and methods of food analysis are prescribed in order to reliably determine antibiotics in food. In this paper the application of ELISA tests for determination of selected antibiotics and sulfonamides in honey is shown. The possibility of using four ELISA tests for the analysis of tetracyclines, streptomycines, chloramphenicol and sulfonamides was examined. Each test was evaluated after application on honey samples spiked with standard solution of a particular analyte. Samples were prepared according to the instructions of the ELISA test manufacturer referring to honey. Results of investigation of all ELISA tests, except for sulphonamides, have shown satisfactory accuracy (73-111%) and precision (14-16%). Recovery for sulfametoxypyridazin was low (40%), and for low tetracycline concentration was somewhat higher than acceptable (139%). The detection limits were in accordance with the limits given by the ELISA kit manufacturer and are also satisfactory in relation to the requirements of the legislation (0.075-3 μg/kg). The test kits can be used to screen the presence of tetracycline, chloramphenicol and streptomycin in the honey, taking into account the obtained validation parameters.

Different analytical techniques for the detection of mycotoxins have been developed in order to control the levels of mycotoxins in food and feed. Conventional analytical methods for mycotoxin determination are involving techniques such as thinlayer chromatography (TLC), high-performance liquid chromatography (HPLC) and gas chromatography (GC). Also, rapid methods for mycotoxin analysis have become increasingly important. Enzyme-linked immuno-sorbent assay (ELISA) is one of the most common rapid methods for determination of these natural contaminants. The aim of this study was to provide a comparison between two different methods of analysis (HPLC and ELISA) for the detection of different mycotoxins using data that originate from commercial proficiency tests. Based on the statistical evaluation of the results for both methods, in three proficiency tests for various mycotoxins (aflatoxins, ochratoxin and zearalenone), it could be concluded that both techniques can equally be used, although ELISA is considered to be the screening one. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. III 46009]

The production of fumonisins by potentially toxigenic Fusarium verticillioides isolates originating from Serbian maize and wheat kernels was tested in vitro. A total of six F. verticillioides isolates were incubated on yeast extract sucrose medium (YESA) for 4 weeks at 25 °C in the dark. Their toxin production potential was tested by applying a modified HPLC method for determination of fumonisins in cereals, since the TLC method gave no results. Analyses were performed on a HPLC-FLD system after sample extraction from YESA and extract cleanup on a SPE column. Although the isolates were tested for fumonisin B1, B2 and B3, only fumonisin B1 was detected. The results showed that all tested isolates had toxigenic potential for fumonisin B1 production. The average fumonisin B1 production of the isolates ranged from 7 to 289 μg/kg, thus indicating a highly variable toxigenic potential among the isolates. Isolate 1282 expressed the highest toxigenic potential for fumonisin B1 production (289 μg/kg), while isolate 2533/A showed a questionable potential for fumonisin production (7 μg/kg). [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. TR 31023]

The quality of drinking water depends on the water sources, but also on the quality of the water distribution system which supplies the water on to the final user. In addition, the possibility of contamination of water used for watering animals in the farm buildings depends on the hygienic conditions on farms. Microbiological quality of water on farms in Serbia has not been one of the main focuses of animal breeders, although according to the Food Safety Law water is considered as food. As feed safety for the animals, which includes microbiological analyses, is an important concern of breeder farmers, it is also important to control the water safety in order not to become a cause of the animal health problems. Change of the water quality is not important only from the sanitary epidemiological point of view, but the presence of different microorganisms, especially fungi, can cause changes in taste and smell, as organoleptic properties of water. According to legal regulations, there is no difference between the quality requirements for drinking water relative to the water supply intended for animals. For the aforementioned reasons, the subject of this study is microbiological control of water samples from the drinkers for animals at farms. The aim of the work is to examine which fungi are possibly present in the water and what their number is. In total, 35 samples of water from pig and poultry farms were tested. The method of direct seeding and filtration was used. The presence of different types of mold (Aspergillus sp., Penicillium sp., Alternaria sp., Mucor sp. and Rhizopus sp., and Candida sp.) was determined. The results indicate the necessity of microbiological control of water for watering of farm animals, which implies the analysis for the presence of molds. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. TR31071]

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]

Mycotoxins are structurally diverse fungal metabolites that can contaminate a variety of dietary components consumed by animals and humans. The aim of this paper was to present the field observations of clinical and pathological consequences on swine health in the cases when Fusarium mycotoxins were detected in swine feed. The material for research included the samples from swine farms located in the region of Vojvodina, where health disorders resembling intestinal problems in different swine categories were detected. The applied research methods included: epidemiological and clinical evaluation, gross pathology examination, bacteriological tissue testing originating from diseased dead animals. The presence of deoxynivalenol (DON), T-2 toxin and zearalenone (ZEA) in thirteen complete swine feed mixtures were analyzed by enzyme-linked immunosorbent assay methods, using Ridascreen®FAST DON, Ridascreen®FAST T2, and Ridascreen®FAST Zearalenon test kits (R-Biopharm, Germany). By clinical and pathological examination, the lesions predominantly located in digestive tract were observed in different swine categories. The problem of persistent enteric infections in suckling piglets and alteration of growth performance were notified in weaners and fatteners. In adult categories, reduced feed consumption, sometimes distinct feed refusal and vomiting were observed. In all examined samples of complete feed mixtures for different swine categories the concentration of DON exceeded the maximum permitted levels, but also the presence of other Fusarium mycotoxins was detected. The obtained results indicate the existence of feed mixtures contamination with low levels of Fusarium mycotoxins and their possible positive interaction with etiological agents present in swine farms. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. TR31071]

In order to develop rapid, inexpensive and, at the same time, reliable method for the analysis of molds of the genus Fusarium as an indicator of the presence of fumonisins in corn samples, possible application of Fourier transform infrared spectroscopy (FTIR) with attenuated total reflection (ATR) technique was examined. The content of fumonisins in contaminated corn samples had previously been quantified by ELISA method. At the spectrum of the sample contaminated with a high concentration of mycotoxins, there was a lack of the peak at 1,743 cm-1, but the peak was observed at 1709 cm-1. To the purpose of result classification the principal component analysis (PCA) and cluster analysis were applied. Conclusions of the two methods were similar both when applying ATR technique in the whole region of the spectrum (1,150-1,770 cm-1) and when the whole spectrum was divided into two regions: 1,150-1,450 and 1,450-1,770 cm-1. However, classification of samples was somewhat better in the ranges 1,150-1,770 and 1,450-1,770 cm-1 . Of the 16 analyzed corn samples, only very contaminated corn sample with 190 mg/kg was correctly classified as compared to the other samples with the content of less than 10 mg/kg. Also, it was found-passing recording of spectra of contaminated corn of the same genotype in order to avoid the possible impact of different hybrids on the spectrum. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. OI 172042]

A total of 14 diverse herbal teas were examined, including: yarrow, basil, St.John’s wort, peppermint, horsetail, nettle, thyme, corn silk, hibiscus, marshmallow, chamomile, rosehip, heather and wild mint. The samples were prepared using the method of microwave digestion, and measurements were performed by the use of inductively coupled plasma mass spectrometry (Cd, Hg, Pb, As, Sb); atomic absorption spectrometry (Mg); emission flame photometry (Ca, K, Na) and spectrophotometry (P). Intervals of variation (mg/kg) for macroelements were: Ca (2738-35399); P (1545-6264); Mg (1647-7816); Na (293-10629) and K (9683-33985), and for toxic elements: Cd (0.014-0.645); Hg (

The past couple of decades have provided considerable details on fungi and the toxins that they produce, as well on the mechanism of toxin action, toxicity and effects on animal and human health. But, since they are natural contaminants, their presence is often inevitable. Fusaria are widespread in all cereal-growing territories of the world, but they are especially common in our geographic area. Therefore, special attention is paid to the prevention and control, and also to the improvement of methods for their detection. Although all collected data were critical for understanding this worldwide problem, managing the impact of these toxins on the feed and food safety is still great practical challenge. There are a number of approaches that can be taken to minimize mycotoxin contamination in this chain: prevention of fungal growth and thus mycotoxin formation, strategies to reduce or eliminate mycotoxins from contaminated feedstuffs or diverting the contaminated products to low risk uses. A control program for mycotoxins from field to table should in­volve the criteria of an HACCP (Hazard Analysis Critical Control Points) approach. It requires an understanding of the important aspects of the interactions of the toxigenic fungi with crop plants, the on-farm production and harvest methods for crops, the production of livestock using grains and processed feeds, including diagnostic capabilities for mycotoxicoses, and all the way to the development of processed foods for human consumption, as well as understanding the marketing and trade channels including storage and delivery of foods to the consumer’s table. A good testing protocol for mycotoxins is necessary to manage all of the control points and in order to be able to ensure a food supply free of toxic levels of mycotoxins for the consumer. [Projekat Ministarstva nauke Republike Srbije, br. III 46009]

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]

Participation in interlaboratory comparison and proficiency testing schemes is important for laboratories to control the work quality. In this study, a sample of naturally contaminated maize was analyzed for the content of ochratoxin A (OTA) in three laboratories in Serbia. Participating laboratories used enzymatic immunoaffinity method (ELISA) for the determination of OTA and selection of the ELISA kit was free. Between-laboratory precision was acceptable as evidenced by Cochran’s C test. Moreover, z-scores for all three laboratories were z < ± 2, which is considered acceptable. Used OTA confirmation methods were thin-layer chromatography (TLC) and high-pressure liquid chromatography (HPLC), with fluorescence detector. The results of different methods were comparable. [Projekat Ministarstva nauke Republike Srbije, br. TR 031071 i br. OI 172042]

The most relevant mycotoxin from the trychotecene group, T-2, causes prominent citotoxic effects. The toxin is a secondary product of fungi from the genus Fusarium that contaminates feed. Oraly intaken, T-2 is absorbed fast in the upper digestive system and within only 3 to 4 hours later reaches liver, kidneys and muscle tissue. Clinical and pathological changes are sometimes not obvious. The case of mycotoxicosis in a breeder flock of chickens, here presented, is aimed to underline the significance of clinical and pathological diagnosis supported with laboratory analysis that gave an objective causative diagnosis. On the farm, the disease occurred suddenly and with total cessation of feed consumption. First cases were recorded in the flock at the age of 42 weeks. Grouping, intensive breathing and lying with overstretched legs and extended neck were symptoms observed in birds. Evident necrosis of beak tips and painful multi-focal necrosis in oral cavity were recorded during the clinical examination. On section, dark unclothed blood was first observed. Other postmortem findings included: filled gizzard with mucosal erosions and easy-removable cuticle, enlarged congested liver with multi-focal necrosis and subcapsulary bleeding. The mortality rate increased by 4%, and the drop of laying rate was by about 18%. The fertility rate decreased by 22%. There was the increased number of rejected hatching eggs, 12%. Culture of the complete diet resulted in approximately 150000 colonies per 1g of Fusarium. T-2 was detected by using ELISA in concentration of 480 μg/kg, which corresponded to the upper limit of maximum permitted concentrations for chickens, according to national legislations. This bylaw interpretation of “tolerable” concentrations of mycotoxins provokes controversy among experts and public. [Projekat Ministarstva nauke Republike Srbije, br. TR 31071]

Analysis of feed for the presence of fungi and mycotoxins is a request necessary to meet in order to ensure a healthy and economical production in livestock. These tests are related to legal regulation which prescribes the maximum legislated content (MLC), both for the presence of mycotoxins and the total number of fungi in certain feeds. Health problems that can occur during the production of animals are sometimes caused by the presence of mycotoxins in the feed. Laboratory testing is a good practice to confirm a suspicion, and allows timely treatment of contaminated feed. Potential problems arise under circumstances when there is a clinical outcome of mycotoxicosis and animal and laboratory findings suggest that the obtained values are below the level that is within the MLC. For these reasons, the subject of our research was to investigate the occurrence of mycotoxins and mold in feed, as well as the clinical presentation for animals that were fed with the feed with allowed values of these agents according to the recommended levels. The aim of this paper was to highlight the problems associated with clinical correlation of sick animals and laboratory findings, and suggest their overcoming. In the period of one year, a total of 176 samples of feed (complete mixture for broilers, corn and soy products) were examined for the presence of fungi, 106 samples were examined for the presence of mycotoxins and 26 flocks of broilers and turkeys were clinically observed. Standard methods were used for isolation of molds and the ELISA test was used for the detection of mycotoxins. Clinical and pathomorphological observation of the flocks was done to determine the natural indicators of production. Studies indicated a problem because clinical and pathomorphological findings in some cases were not correlated with laboratory findings of molds and mycotoxins in the feed, and in some cases it did not necessarily mean that the animals were healthy. Synergism and cumulative effects of mycotoxins, on the one hand, and the characteristics of each species and product category on the other hand, can create specific circumstances that can lead to disease and can increase even though the values prescribed by legislation have been met. [Projekat Ministarstva nauke Republike Srbije, br. TR 031071]

The presence of fumonisin has not been regulated in the legislation of the Republic of Serbia. Therefore, the data on contamination of cereals, especially corn, which is highly susceptible to contamination by this toxin, are not sufficient. This paper presents the results of testing the corn samples collected in the autumn 2009 on the territory of Bačka. Samples were analyzed for the contents of fumonisins and it was determined whether there is a correlation between the moisture content, total number and class of fungi, as well as the content of aflatoxin, ochratoxin and zearalenone. Using enzymatic immunoaffinity method it was discovered that the highest percentage of samples were contaminated with fumonisins, which was probably due to the presence of Fusarium molds as the most abundant ones. The positive samples contained fumonisin in the concentrations from 0.030 to 1.52 mg kg−1. The influence of the climate and moisture content of grain on fungal contamination and mycotoxin production was analyzed in order to investigate the predictability of the presence of mycotoxins.

Mycotoxins, as secondary metabolic products of molds, are common contaminants of raw feed materials and compound feeds. Depending on the agro-meteorological and storage conditions, molds can contaminate grains and produce mycotoxins in the field, before and after harvest and during storage. Way of preventing animal mycotoxicoses and transfer of mycotoxins to humans through food chain is regular inspection on mycotoxicological feed safety. This paper presents the results of examination of aflatoxin, ochratoxin and zearalenone in 89 samples tested under laboratory conditions during a one year period. The analyses of types of samples, contamination, and their origin demonstrated the need for preventive control of mycotoxin content, primarily in grains. The results of testing the content of aflatoxin in milk indicate the existence of risks to human health. In order to protect humans and animals from mycotoxicological contamination, we propose the use of the system hazard analysis and critical control point (HACCP), which has been proved to be an effective strategy in food safety control. The basic principles of HACCP approach in the production of feed and foodstuffs, as well as the compliance and harmonization of legislations with those in the European Union, in the field of mycotoxicological tests, are the best prevention against mycotoxin effects on health and economy. Implementation of HACCP system currently presents one of the basic preconditions for the export of our products and their placement on the European market.

Dogs are animals that are most often kept as pets in the cities. Their health problem may be the cause of infections of humans and animals. Skin changes and etiology factors present important segment of the diseases that disturb health of the pets. The objective of this work was mycology examination of scarifications and skin swabs from dogs with clinical symptoms. The aim was to find out which fungi species can be isolated from the changed parts of the skin, and whether is possible that, besides dermatophyte, saprophyte fungi from the environment may also be the cause of the changes, and to reveal their effect on the host. During a one year period, 67 swabs and scarifications from dogs were examined to detect the presence of fungi. The samples were streaked on Sabourdaud's dextrose agar and incubated for 10-21 days at 25°C. In microscopis examination according to their shape, and color, the colonies were identified as conidia, macroconidia and conidiaophora. From 59, of total 67 samples, the following saprophyte fungi were isolated: Aspergillus sp., Penicillium sp., Alternaria sp., Mucor sp. and Fusarium sp. Occurrence of these fungi means that a considerable increase of this microbiological flora may be expected in homes of the owners. This may be the cause of systemic mycosis and allergies in animals and humans, as well as a possibility of contaminated food and incidence of mycotoxicosis.

The possibility of the liquid chromatographic determination of fumonisins B1 (FB1) and B2 (FB2) in corn samples with a reused immunoaffinity column (IMA) for the clean-up of the samples was investigated. After optimization of the chromatographic determination of FB1 and FB2 derivatized with o-phthaldialdehyde- 2-mercaptoethanol, the efficiency of the clean-up of spiked corn extracts with reuse of the IMA columns was studied, both with and without column regeneration. It was found that the IMA column, designated for single-use only, can be used at least five times without regeneration and additional five times after regeneration. Regeneration consists of leaving the phosphate buffer saline solution on the column for one day at 4 ºC. The efficiency of the columns was tested by determining the recovery of FB1 and FB2, as well as the reproducibility of the determinations. The mean recoveries of FB1 and FB2 from corn spiked with FB1 at 1.0 μg/g and with FB2 at 0.5 μg/g (on the basis of 10 measurements) were 88.7%(RSD 10.2%) and 90.5%(RSD 6.1 %), respectively.

The efficiencies of different clean-up procedures for crude corn extract from corn samples naturally contaminated by fumonisins B1 and B2 were compared. These procedures precede liquid chromatography determination with fluorescence detection. The efficiencies of immunoaffinity columns (IMA) strong anion exchange columns (SAX), as well as columns with reversed-phase C18 (RP C18) were investigated. No significant differences in the obtained results were found, regardless of the crude extract clea-nup procedure. However, the use of IMA columns for clean-up provided better chromatographic resolution, with the clean-up procedure being the simplest and the fastest. Also, because of the possibility of IMA column regeneration, it is possible to prepare ten samples on one column, so all in all, the lower price of SAX and RP C18 columns is of no great significance.

An expert system (ES) to solve the problem of choosing an optimal procedure for the determination of fumonisins in corn samples was developed, having in mind that these toxins most frequently contaminate this particular cereal. In constructing the ES use was made of the deterministic approach starting from the assumption that the experts in the field have a profound knowledge about the problem in question. The ES knowledge base contains the solutions that have been published in the pertinent literature, as well as some solutions and recommendations, which we have developed and introduced. On the basis of this information, as well as on the basis of the demanded method detection limit, available equipment, chemicals, as well as the time the experimenter has at his disposal for the determination, the ES proposes a procedure for solving the given analytical problem, starting from sampling, preparation of all the necessary solutions, the appropriate apparatus, probe preparation, the mode of determining results, calculation of the results, and provides a survey of all the relevant literature references. The base of ES is a shell, which can work under a variety of Microsoft Windows operating systems. In the development of ES and its adaptation for users who are not familiar with computer techniques, different tools, which operate with Microsoft Windows operating systems, as well as the tools within Microsoft Office are used.

Copyright of Matica Srpska Journal for Natural Sciences is the property of Matica Srpska, Department of Natural Studies and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Fast, simple high-performance liquid chromatography (HPLC) method with refractive index detection (RID) was optimized and validated for the quantification of lactose in milk and dairy products. The method showed good linearity with determination coefficient 0.9975. The limit of detection was 0.04 mg/mL, and the limit of quantification 0.12 mg/mL. The relative standard deviations for repeatability were 4.00 and for reproducibility 4.98 in reference material, while in different tested matrix the relative standard deviations for repeatability were in range 2.58‒6.51. Average efficiency value was 97%. The applicability of the method was confirmed by its application in different samples. The presence of this sugar was not detected (lower than 0.1%) in the samples of milk and yogurt labelled as lactose-free, as well as in parmesan, cheddar, gouda and trappist cheese samples. In various dairy products the measured lactose content had values from 0.493±0.026% in home-made rolled cheese to 4.42±0.180% in cooking sour cream. [ABSTRACT FROM AUTHOR]

Five physicochemical parameters (water content, electrical conductivity, total acidity (pH), ash mass fraction and concentration of free acids) were analyzed in 15 sunflower honeys collected from several localities in Vojvodina, Serbia. The mean values of analyzed honeys were: water content 16.87%; concentration of free acids 27.43 mEq/kg; electrical conductivity 0.34 mS/cm; pH 3.64 and ash mass fraction 0.13%. The selected physicochemical characteristics of all honey samples from Serbia analyzed in this research can be considered to be within the parameters expected for sunflower honey in general. The values for ash mass fraction, electrical conductivity and concentration of free acids in all sunflower honey samples showed similar trends. High correlation was established between electrical conductivity and ash mass fraction. Statistically significant difference (p=0.05) was established only for average values of free acids concentration between honey samples originating from the localities Kanjiža and Čelarevo. All of the analyzed honey samples were found to meet national and European legislation for investigated parameters. [ABSTRACT FROM AUTHOR]

Copyright of Matica Srpska Journal for Natural Sciences is the property of Matica Srpska, Department of Natural Studies and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Chemical Industry / Hemijska Industrija is the property of Association of Chemical Engineers and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)