Saša Krstović

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 deoxynivalenol in small-grain samples from 2009/10 harvest season.

Fusarium head blight (FHB) is present in all growing regions of small grains and causes significant losses in yield and grain quality. In our environmental conditions, dominant species is Fusarium graminearum Group 2. During 2009/10 there was a significant Fusarium infestation on wheat, barley and triticale. The aim of this study was to examine the contents of deoxynivalenol (DON) in cereal samples taken after 2009/10 harvest season. We analyzed 22 NS varieties of small grains from Rimski Sancevi, including 16 varieties of winter wheat, one facultative wheat variety, four varieties of winter barley and one variety of triticale. Analytical methods based on clean-up by solid-phase extraction (SPE) columns and detection by liquid chromatography were used. Fifteen out the 22 analyzed samples were positive for the presence of DON at a mean level of 0.537 mg/kg. The highest concentration was 1.952 mg/kg. These findings were in correlation with percentage of the Fusarium damaged kernels.

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.

Mycobiota on common wheat ( Triticum aestivum) and spelt (Triticum aestivum ssp. spelta) grains from the region of Vojvodina in 2015

The incidence of mycobiota on common wheat (Triticum aestivum) and spelt (Triticum aestivum ssp. spelta) samples, collected during the harvest in 2015, was investigated. The obtained results showed that more genera of mycobiota were isolated from the common wheat grains than from the spelt grains. The most frequently isolated species from common wheat grains belonged to genus Alternaria (41.7%), followed by Fusarium (15.2%), while the incidence of this mycobiota on the spelt grains were 32.4% and 10.4%, respectively. Aspergillus flavus was identified in 40.0% wheat samples, with the incidence of 2.0%. Additionally, this study was undertaken in respect of the occurrence and toxigenic potential of A. flavus isolates from these small grain cereals. A simple screening method was applied to determine toxigenic profiles (aflatoxins production) of A. flavus isolates from common wheat. The results revealed the importance of precise investigation of mycobiota distribution on common wheat and spelt grains, and especially the investigation of toxigenic potential of A. flavus.

The Impact of Organic Agriculture on Biodiversity Conservation and Milk Quality for Traditional Cheese Production

Summary Organic farming represents agricultural practice that could contribute to the preservation of biological diversity and breeding of cows with the most desired milk quality attributes. Milk composition could vary widely according to genetic diversity of the animals and different feeding systems. These are related to higher dry matter content, fat, protein and a more favorable ratio of the saturated/unsaturated fatty acids, which is important in traditional cheese production. Standard chemical analyzes were performed and this paper shows the differences in the chemical properties and the fatty acid profile of milk, depending on the different breeds and breeding methods of animals. Simmental milk (indoors) was most abundant in dry matter and fat (13.01 and 4.30%, respectively) while protein and casein level was the highest in the Busha milk (3.67 and 2.63%, respectively). Holstein Friesian milk (organic) possessed a more constant composition and, together with Busha appropriate hygienic quality of milk (low level of somatic cells and total bacteria count). Also, milk from Holstein Friesian cows (organic) was disposed with better nutritional quality and more desirable fatty acid profile (SFA (63.40%), MUFA (30.79%) and PUFA (5.72 %)). On the other hand, Holstein Friesian (conventional) milk contained SFA (67.45%), MUFA (29.27%) and PUFA (3.28%) while Simmental (indoors) higher values of SFA (71.21%) and less MUFA (25.39%) and PUFA (3.40%). There are various ways to preserve biodiversity and the application of organic production standards in the traditional cheese production contributes to obtaining safer, quality products which are more recognizable on the market.

Quality of Milk for Cheese Production on Registered Agricultural Holdings in Vojvodina

Summary Currently, milk producers in Vojvodina on registered agricultural holdings (RAHs) have great experience and knowledge in managing their farms, including primary production, processing and sales. However, for a smaller number of manufacturers, there is still room for organizational and technological improvement of production. Nowadays, goat breeding is a very important part of sustainable production, rural development, and represents a very important part of rural development and employment of people. The course of goat breeding in our country is milk-meat, where milk is usually a priority. For the successful production of cheese, the quality of raw milk plays a critical role. It affects the quality of cheese in terms of a chemical composition, microbiological quality, the presence of chemical residues and organoleptic properties. Cheese is mostly made from cow, goat and sheep milk. The valuable components of milk are proteins and fats. These can also be defined as parameters of utilization, since they indicate how much cheese can be obtained from milk. On average, cow milk contains 3.64% fat, 3.22% protein, and 8.52% non-fat dry matter (NFDM). Higher differences in milk fat content (minimum 3.25%, maximum 4.36%) were found in milk from RAHs. Recently, the production of milk with higher fat content has become important, since in Serbian milk there is not enough milk fat, so some processors are obliged to import it in the form of butter and cream. In addition to the chemical composition, the microbiological quality of milk is important to maintain successful cheese production. Regarding our findings, the standard plate count (SPC) and the somatic cell count (SCC) in samples from most RAHs did not exceed the values specified in Regulation (EC) 853/2004. Moreover, goat and sheep milk was in agreement with the technological quality of milk for cheese production, in terms of chemical composition.

Preliminary Results on Deoxynivalenol Degradation in Maize by UVA and UVC Irradiation

Summary The aim of this work was to investigate the possibility of using UV irradiation for degradation of deoxynivalenol (DON) in naturally contaminated maize samples. The study was carried out by varying the distance of the contaminated maize from the UVA (368 nm) and UVC (254 nm) light source and duration of exposure of contaminated maize to UV irradiation. Two control samples of maize were used for the irradiation procedure, at DON levels of 1.902 mg/kg and 5.334 mg/kg. The samples were exposed to both UVA and UVC light at two different distances from UV lamp (15 and 30 cm) during three exposure intervals (30, 60 and 120 minutes). After irradiation DON content was determinated so the reduction levels could be quantified. Generally, the results showed reduced DON content in treated samples, but they were not consistent. The most probable reason for this was a very uneven DON distribution in naturally contaminated samples. For this reason, further research must be performed and should include irradiation of artificially inoculated samples with consistent DON distribution, the amount of irradiated sample needs to be enlarged and the higher number of replicates should be analyzed. As an additional improvement, an increase in frequency of sample mixing during the irradiation procedure needs to be done.

Quality of Hard Cheese Made from Value Aded Organic Goat Milk

Summary Products with added value are all those products which, in addition to requirements set by laws of food safety and quality, meet the additional requirements. The added value of products resulting from its higher nutritional and commercial value and very often involve products originating from organic production or products with geographical indications. Consumer knowledge of production values has increased exponentially and has fuelled a demand for healthy, quality products such as goats’ milk and cheeses. The single most important factor affecting cheese quality and yield is the composition of the milk, particularly the concentrations of fat and casein. Nutritional value of goat cheese derives from its energy value, content of essential fatty and amino acids, the content of vitamins, minerals and its digestibility. In this paper, organic goat milk and hard goat cheese were analyzed for fatty and amino acids profile. In addition, cheese was assayed for fat, protein, moisture, total solids, Ca, P, Mg and pH. The evaluation of the cheeses was performed to establish the relationship between quality and composition of milk and cheese. Obtained values for saturated, monounsaturated and polyunsaturated fatty acid content in cheese were on average 42.0, 54.4, and 3.60 %, respectively. Levels of glutamic, aspartic acid, lysine and leucine significantly increased in cheese comparing with milk samples. Mean values for fat in dry matter in cheese was 47.1 %, while for pH this value amounted 5:55.