Jovana Kos

Alternaria toxins in wheat from the Autonomous Province of Vojvodina, Serbia: a preliminary survey

Although Fusarium species remain a main source of mycotoxin contamination of wheat, in recent years, due to the evident climatic changes, other mycotoxigenic fungi have been recognised as important wheat contaminants. Alternaria species, especially A. alternata, have been found as contaminants of wheat as well as wheat-based products. Under favourable conditions A. alternata very often produce alternariol (AOH), alternariol monomethyl ether (AME), tenuazonic acid (TeA) and others Alternaria toxins. The aim of the present study was to examine the presence of three Alternaria toxins (AOH, AME and TeA) in wheat samples harvested during three years (2011–13). To this end, 92 samples were collected during wheat harvesting from different growing regions of the Autonomous Province of Vojvodina, which represents the most important wheat-growing area in Serbia. The presence of Alternaria toxins was analysed by HPLC with electrospray ionisation triple quadrupole mass spectrometry (LC-ESI-MS/MS). Among all the analysed wheat samples, 63 (68.5%) were contaminated with TeA, 11 (12.0%) with AOH and 6 (6.5%) with AME. Furthermore, the maximum and mean toxin concentrations were 2676 and 92.4 µg kg−1, 48.9 and 18.6 µg kg−1, and 70.2 and 39.0 µg kg−1 for TeA, AOH and AME, respectively. Co-occurrence of three Alternaria toxins in wheat samples was detected in six samples; a combination of two toxins was found in two samples; and 64 samples contained one toxin. The results showed that among 92 analysed wheat samples, only 20 (21.7%) samples were without Alternaria toxins. The presence of Alternaria toxins was also investigated in terms of weather conditions recorded during the period of investigation, as well as with the sampling region. This study represents the first preliminary report of the natural occurrence of Alternaria toxins in wheat (Triticum aestivum) from Serbia.

Aflatoxins contamination of maize in Serbia: The impact of weather conditions in 2015

ABSTRACT In recent years climate changes recorded in temperate regions of Europe have led to aflatoxin (AF) contamination of maize. Thus, the aim of this study was to investigate the influence of weather conditions on levels of aflatoxin B1 (AFB1), aflatoxin B2 (AFB2), aflatoxin G1 (AFG1) and aflatoxin G2 (AFG2) in 180 maize samples collected from the main maize-growing regions (Western Bačka, North Banat, South Banat and Central Serbia) in Serbia after harvest in 2015. The concentrations of AFs were determined by a validated HPLC method with post-column derivatisation and fluorescence detection (HPLC-FLD). The presence of AFB1, AFB2, AFG1 and AFG2 was detected in 57.2%, 13.9%, 5.6% and 2.8% of maize samples in the concentration ranges of 1.3–88.8 µg kg–1, 0.60–2.8 µg kg–1, 1.8–28.5 µg kg–1 and 2.1–7.5 µg kg–1 respectively. The recorded smaller amount of precipitation and especially higher air temperatures during the summer of 2015 were favourable for AF production, which resulted in 32.2% and 21.1% of samples being unsuitable for human consumption, since AFB1 and the sum of AFs concentrations were above 5.0 and 10.0 µg kg–1 respectively. Furthermore, the findings in this study indicate that the microclimate conditions in the investigated regions had a great influence on the contamination frequency of maize with AFs. The highest percentage of samples unsuitable for human consumption, considering both AFB1 and total AFs content were 72.5% and 51.5% respectively from Central Serbia, whilst the lowest percentages of 15.6% and 6.2% respectively were found in Western Bačka. These findings confirmed that maize should be continuously monitored in order to protect human and animal health from the harmful effects caused by AFs contamination.

Presence of aflatoxins in cereals from Serbia

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.

Incidence of deoxynivalenol in Serbian wheat and barley.

One hundred thirty-nine small-grain cereal (wheat and barley) samples collected during the 2010 harvest in Serbia were tested for deoxynivalenol (DON) contamination. Samples were classified into four different groups and then analyzed by analytical methods based on cleanup by solid-phase extraction and detection by liquid chromatography after the validation. Limits of detection of DON were 18 and 22 μg/kg for wheat and barley, respectively, and limits of quantification were 60 and 73 μg/kg for wheat and barley, respectively. Obtained recovery values for wheat and barley samples ranged from 93.7 to 105.8% and from 84.7 to 89.2%, respectively. Analysis of 128 wheat samples showed that 100 (78.1%) of them were contaminated with DON at the levels ranging from 64 to 4,808 μg/kg. The contamination level of even 16 (12.5%) samples was above the established maximum tolerable limits adopted by the European Commission (EC) and Serbian regulation. In the 11 examined barley samples, DON was found in 3 (27.3%), with the levels ranging from 118 to 355 μg/kg, although none of the samples were contaminated above the limit for this cereal. The results obtained were analyzed as a function of climatic conditions and compared with the previous data on the presence of DON in Serbia.

Aflatoxins in maize harvested in the Republic of Serbia over the period 2012–2016

ABSTRACT Aflatoxins (AFs) are one of the most frequent contaminants in maize. The Republic of Serbia represents a leader in terms of maize production and exports in Europe. In recent years, Serbia faced climate changes. Therefore, the main objective of this study was to examine AF occurrence in 3000 maize samples collected during 2012–2016. In maize samples from 2012, 2013, 2015, and 2016, AFs were detected in 72.3%, 24.7%, 36.7%, and 5.0% of the samples, in concentration ranges of 1.0–111.2, 1.2–65.2, 1.1–76.2, and 1.3–6.9 µg kg−1, respectively. Contrary to this, in maize samples from 2014, no AFs were detected. Analysis of weather conditions indicates that 2012 was characterised by extreme drought conditions, 2013 and 2015 by lack of precipitation and high air temperatures, 2014 as the rainiest year in these years, while 2016 had moderate weather conditions.

Aflatoxin, zearalenone, deoxynivalenol and fumonisin contamination of maize from the Autonomous Province of Vojvodina

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 Immunisorbent 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.

The choice of preparation method for the determination of Alternaria toxins from wheat samples by LC-MS/MS

Cereals are the primary source of human diet, wheat being the third most produced grain worldwide, and in Serbia second most produced grain, just behind corn. As a result of climate change and global warming, frequent occurrences of mycobiota on steep grains can produce a negative impact on the safety of food products and their quality, which inevitably leads to large economic losses. Although Fusarium spp. remains a main source of mycotoxins contamination of wheat, in recent years, due to the evident climatic changes affecting agricultural production, other mycotoxigenic fungi have been pointed out as important wheat contaminants. Among them are the fungi of the genus Alternaria, especially A. alternata, which under favourable conditions, produces mycotoxins such as alternariol, alternariol monomethyl ether, tenuazonic acid, and other Alternaria toxins. Taking into account the toxicity of metabolites produced by certain species of fungi of the genus Alternaria in the system from farm to table, it is necessary to develop specific and sensitive analytical methods in order to implement systematic controls of occurrence of Alternaria toxins. Liquid chromatography coupled to (tandem) mass spectrometry (LC-MS/MS) has become the technique of choice for the detection and quantification of Alternaria toxins in food and feed. There are several limiting factors such as the efficiency of sample cleanup and the lack of reference materials for food and feed. The aim of this study was to choose the most suitable preparation method for the determination of Alternaria toxins from wheat samples by LC-MS/MS technique based on published sample preparation methods, with possible modifications, which are used in analysis of mycotoxins. Modified method of wheat samples preparation by extraction with ethyl acetate was selected as acceptable based on extraction efficiency of analytes of interest.