Cadmium and lead in fresh vegetables and vegetable products sold on the local market in the Republic of Serbia, 2018-2021.

Cadmium (Cd) and lead (Pb) concentrations were determined in samples of 31 species of vegetables (n = 719) and in vegetable products (n = 17), collected during the period January 2018 to September 2021. These originated from 33 countries, including Serbia. The samples were analysed by inductively coupled plasma - optical emission spectrometry (ICP-OES). Overall, Cd and Pb were found above the limit of detection in 123 (16.7%, n = 736) and 90 (12.2%; n = 736) samples, respectively. According to the former legislation, valid until the end of August 2021, the maximum levels (MLs) of Cd and Pb were exceeded in 1 and 2 samples of vegetables, respectively. Regarding the EU and Serbian legislation which is valid since September 2021 the MLs of Cd and Pb for vegetables were exceeded in 7 samples: Cd in 5 and Pb in 2 samples. In addition, 3 vegetable product samples exceeded the MLs for both cadmium and lead according to both former and current regulations.

Cadmium and lead in fresh fruits and fruit products sold on the local market in the Republic of Serbia, 2018-2021.

Cadmium (Cd) and lead (Pb) concentrations were determined in 737 samples of 39 species of fruits and of processed fruits (n = 13), collected during the period January 2018 to September 2021. Fruits and fruit products originated from 47 countries, including Serbia. Samples were analysed by inductively coupled plasma - optical emission spectrometry (ICP-OES). Overall, Cd and Pb were found above the limit of detection (LOD) in 97 samples (13.9%). Cd and Pb concentrations were below the LOD in all samples of fruit products. According to the valid regulations before September 2021, the maximum level (ML) of Cd for analysed fruits was exceeded in only 1 sample (0.14%; n = 737), while concentrations of Pb in each analysed fruit sample was below the ML. According to the legislative regulations as set after September 2021, the maximum levels of Cd and Pb for fruits were exceeded in 5, respectively 1, of the samples, so 6 in total (0.81%; n = 737).

Screening of Native Trichoderma Species for Nickel and Copper Bioremediation Potential Determined by FTIR and XRF.

Soil pollution with heavy metals is a serious threat to the environment. However, soils polluted with heavy metals are considered good sources of native metal-resistant Trichoderma strains. Trichoderma spp. are free-living fungi commonly isolated from different ecosystems, establishing endophytic associations with plants. They have important ecological and biotechnological roles due to their production of a wide range of secondary metabolites, thus regulating plant growth and development or inducing resistance to plant pathogens. In this work we used indigenous Trichoderma strains that were previously isolated from different soil types to determine their tolerance to increased copper and nickel concentrations as well as mechanisms of metal removal. The concentrations of bioavailable metal concentrations were determined after extraction with diethylene-triamine pentaacetate (DTPA)-extractable metals (Cd, Cr, Co, Cu, Pb, Mn, Ni, and Zn) from the soil samples by inductively coupled plasma-optical emission spectrometry (ICP-OES). Two indigenous T. harzianum strains were selected for copper tolerance, and three indigenous T. longibrachiatum strains were selected for nickel tolerance tests. Strains were isolated from the soils with the highest and among the lowest DTPA-extractable metal concentrations to determine whether the adaptation to different concentrations of metals affects the mechanisms of remediation. Mechanisms of metal removal were determined using Fourier-transform infrared spectroscopy (FTIR) and X-ray fluorescence spectroscopy (XRF), non-destructive methods characterized by high measurement speed with little or no need for sample preparation and very low costs. Increased DTPA-extractable metal content for nickel and copper was detected in the soil samples above the target value (TV), and for nickel above the soil remediation intervention values (SRIVs), for total metal concentrations which were previously determined. The SRIV is a threshold of metal concentrations indicating a serious soil contamination, thus confirming the need for soil remediation. The use of FTIR and XRF methods revealed that the presence of both biosorption and accumulation of metals in the Trichoderma cells, providing good bioremediation potential for Ni and Cu.

Cadmium, lead, mercury and arsenic in fresh vegetables and vegetable products intended for human consumption in the Republic of Serbia, 2015-2017.

The concentrations of cadmium (Cd), lead (Pb), mercury (Hg) and arsenic (As) were determined in 455 samples of 27 species of vegetables and 28 different processed vegetables collected during the period from January 2015 to December 2017. Vegetables (n = 387) and vegetable products (n = 68) originated from 31 countries, including Serbia. The samples were analysed by inductively coupled plasma - optical emission spectrometry (ICP-OES). The concentrations of Cd, Pb, Hg and As in the vegetables and vegetable products were compared to the maximum levels set by the European Union and the Serbian legislation. The concentration of mercury was less than the limit of detection in each analysed sample. One or multiple measurable toxic metals (Cd, Pb and/or As) were found in 250 samples (54.9%; n = 455). According to the Regulations which were valid until the end of August 2021, the maximum levels of Cd, Pb and As were exceeded in 19 samples (4.2% of the samples of vegetable and vegetable products; n = 455), i.e. in 13 samples of vegetables: Cd in three, Pb in nine and As in one sample and in 6 samples of vegetables products: Cd in three, Pb in one and As in two samples. Regarding the new EU and Serbian legislation which is valid since September 2021 the maximum levels of Cd and Pb for vegetables and vegetable products were exceeded in 118 samples (25.9% of the samples of vegetable and vegetable products; n = 455), i.e. in 95 samples of vegetables: Cd in 67 and Pb in 28 samples and in 23 samples of vegetable products: Cd in 20 and Pb in 3 samples.

Cadmium, lead, mercury, and arsenic in fresh fruits and fruit products intended for human consumption in the Republic of Serbia, 2015-2017.

The European Commission has established legislation for toxic metals in certain foodstuffs in order to protect public health already in 1993. After several amendments, new maximum levels for cadmium and lead in certain foods were set as per 30 and 31 August 2021 for lead and cadmium, respectively. The new Serbian Regulation on "maximum levels of certain contaminants in food" is fully harmonised with this European legislation. The concentrations of cadmium (Cd), lead (Pb), mercury (Hg), and arsenic (As) were determined in 832 samples of 39 species of fruits and processed fruits, collected during the period January 2015 to December 2017. Fruits and fruit products originated from 45 countries, including Serbia. Samples were analysed by inductively coupled plasma - optical emission spectrometry (ICP-OES). Concentrations of cadmium, lead, mercury, and arsenic in fruits and fruit products were compared to these maximum levels (MLs). Overall, measurable Cd, Pb, Hg, and As were found in 377 samples (45.3%). According to the former regulations, the maximum levels of Cd and Pb for analysed fruits and fruit products were exceeded in only 10 samples (1.20%; n = 832): Cd in 6 and Pb in 4 samples, but according to the latest regulations, the maximum levels of Cd and Pb for fruits were exceeded in 196 of the samples (23.9%; n = 820): Cd in 191 and Pb in 5 samples. The increase of ML exceedances shows that attention needs to be paid for compliance of food to the recent MLs for these metals.

Influence of selenium yeast on the growth, selenium uptake and mineral composition of Coriolus versicolor mushroom.

The ability of Coriolus versicolor medicinal mushroom to grow and accumulate selenium during submerged cultivation in a selenium-fortified medium is examined in this paper. For selenium supplementation, commercial selenium yeast was used. Control, nonenriched sample and reference cultures cultivated in the medium enriched with commercial yeast Saccharomyces cerevisiae were also prepared. The mushroom demonstrated a high ability to accumulate selenium from the added source (around 970 and 1,300 µg/g of dry mycelium weight for samples enriched with selenium in a concentration of 10 and 20 mg Se/L, respectively). The addition of selenium significantly (p ≤ .05) increased the biomass yield, whereas the addition of nonenriched yeast had no significant (p ≤ .05) impact. Furthermore, regression analysis showed statistically significant (p ≤ .05) and positive correlations between the content of Se and Fe (r = .92), Se and Cu (r = .92), Se and Mn (r = .98), and Se and Sr (r = .96), suggesting that selenium incorporation was followed by incorporation of these elements, and led to mineral enrichment of the obtained mycelium. Methanol extracts prepared from mycelium biomass demonstrated a better inhibitory effect on Gram-positive bacterial strains with minimal inhibitory concentrations between <0.3125 and 40 mg/ml. The obtained results showed that selenium yeast could be used for obtaining a potential novel food supplement: mushroom biomass with high selenium content and enhanced mineral composition.

Toward identification of the risk group of food products: Chemometric assessment of heavy metals content in confectionery products.

The main raw material for cookies production is wheat flour (white or wholemeal/integral) as a nutritionally highly valuable component. In addition to the benefits it brings, this raw material is also a potential source of contamination with residues of heavy metals originating from soil and plant protection agents. Therefore, it is necessary to analyze their concentrations in both wheat flour and final products, since the wheat flour is often present in cookies and related confectionery products in a proportion >60 or 70%. The aim of this paper was to determine the content of heavy metals, including highly toxic ones (As, Cd, Hg and Pb) and essential metals with potential toxic effects (Fe, Cu, Cr, Co, Mn, Ni, Zn) in cookies, waffles and crackers available in local markets in the Autonomous Province of Vojvodina, Republic of Serbia. The present study is focused on chemometric estimation of the risk group of confectionery products containing wheat flour in an easy and efficient way. Hierarchical cluster analysis, principal component analysis, linear discriminant analysis and the sum of ranking differences analysis were applied for this purpose as chemometric tools with substantially different theoretical bases. The obtained results indicated that there is a specific group of cookies with a relatively high content of heavy metals. The group of crackers contained lower concentrations of heavy metals than the other groups of studied products. The results of the sum of ranking differences analysis indicate that there is no strict separation between the samples regarding the ratio among heavy metals contents.

Copper-tolerant yeasts: Raman spectroscopy in determination of bioaccumulation mechanism.

Modern, efficient, and cost-effective approach to remediation of heavy metal-contaminated soil is based on the application of microorganisms. In this paper, four isolates from agricultural and urban contaminated soil showed abundant growth in the presence of copper(II) sulfate pentahydrate (CuSO4·5H2O) up to 2 mM. Selected yeasts were identified by molecular methods as Candida tropicalis (three isolates) and Schwanniomyces occidentalis (one isolate). C. tropicalis (4TD1101S) showed the highest percentage of bioaccumulation capabilities (94.37%), determined by the inductively coupled plasma optical emission spectrometry (ICP-OES). The Raman spectra of C. tropicalis (4TD1101S) analyzed in a medium with the addition of 2 mM CuSO4·5H2O showed certain increase in metallothionein production, which represents a specific response of the yeast species to the stress conditions. These results indicate that soil yeasts represent a potential for practical application in the bioremediation of contaminated environments.

Cadmium in liver and kidneys of domestic Balkan and Alpine dairy goat breeds from Montenegro and Serbia.

Concentrations of cadmium (Cd) were determined in the samples of 144 animals around 1 and of 144 animals around 4 years old. Cd was analysed by inductively coupled plasma-optical emission spectrometry (ICP-OES), after microwave digestion. Cd concentrations were higher (p < 0.05) in kidney than in liver and higher (p < 0.05) in older animals than in young ones. In domestic Balkan goat which was raised in a free-ranged system Cd accumulation was lower (p < 0.05) than in Alpine goat raised in an intensive production system. Geographic region did influence Cd accumulation only in older animals. Higher Cd levels (p < 0.05) were determined in goats from Serbia. The highest obtained Cd concentrations in both tissues were lower than maximum levels set by European and national legislation for ruminants (cattle and sheep).

Cadmium and lead in female cattle livers and kidneys from Vojvodina, northern Serbia.

Concentrations of cadmium (Cd) and lead (Pb) were determined in livers (n = 52) and kidneys (n = 52) of female cattle (345-2717 days old) from dairy farms in the region Vojvodina. Cd and Pb were analysed by inductively coupled plasma-optical emission spectrometry, after microwave digestion. Cd and Pb concentrations did not exceed the Serbian and European maximum set limits in any sample. The Cd concentrations in the livers and kidneys ranged from 0.033 to 0.151 mg kg-1 wet weight and from 0.055 to 0.510 mg kg-1 wet weight, respectively. The corresponding Pb concentrations were 0.015-0.159 mg kg-1 wet weight and 0.021-0.196 mg kg-1 wet weight, respectively. Mean Cd and Pb concentrations were significantly lower (p < 0.001) in the liver (0.072 and 0.053 mg kg-1 wet weight) than in the kidney (0.190 and 0.075 mg kg-1 wet weight). There were good correlations between Cd in liver and Cd in kidney, Pb in liver and Pb in kidney, Cd level and age and Pb level and age in both tissues.