Aflatoxins in maize, milk and dairy products from Serbia

This study presents data on the occurrence of aflatoxins B1, B2, G1 and G2 in maize and aflatoxin M1 (AFM1) in milk and dairy products from Serbia in 2022. A total of 100 maize samples were analysed using liquid chromatography tandem mass spectrometry, while 107 cow and goat milk, besides dairy products were tested with an ELISA method. Aflatoxins contaminated 78% of the maize samples, with aflatoxin B1 as the most prevalent aflatoxin, also at the highest determined level. All milk samples tested positive for AFM1, while contamination in dairy products ranged from 14% to 100%. The hot and dry weather during the 2022 maize growing season, characterised by moderate to extreme drought conditions, significantly increased maize contamination with aflatoxins, impacting subsequent milk and dairy products contamination. The findings of this study confirm the continuous trend and persistent challenge in Serbia concerning the prevalence of aflatoxins in maize and milk, closely linked to climate change.

Comparison of the Efficiency of Selected Disinfectants against Planktonic and Biofilm Populations of Escherichia coli and Staphylococcus aureus

The aim of this study is to compare the efficacy of selected food disinfectants on planktonic populations of Staphylococcus aureus and Escherichia coli and on the same microorganisms (MOs) incorporated in a biofilm. Two disinfectants were used for treatment: peracetic acid-based disinfectant (P) and benzalkonium chloride-based disinfectant (D). Testing of their efficacy on the selected MO populations was performed using a quantitative suspension test. The standard colony counting procedure was used to determine their efficacy on bacterial suspensions in tryptone soy agar (TSA). The germicidal effect (GE) of the disinfectants was determined based on the decimal reduction ratio. For both MOs, 100% GE was achieved at the lowest concentration (0.1%) and after the shortest exposure time (5 min). Biofilm production was confirmed with a crystal violet test on microtitre plates. Both E. coli and S. aureus showed strong biofilm production at 25 °C with E. coli showing significantly higher adherence capacity. Both disinfectants show a significantly weaker GE on 48 h biofilms compared to the GE observed after application of the same concentrations on planktonic cells of the same MOs. Complete destruction of the viable cells of the biofilms was observed after 5 min of exposure to the highest concentration tested (2%) for both disinfectants and MOs tested. The anti-quorum sensing activity (anti-QS) of disinfectants P and D was determined via a qualitative disc diffusion method applied to the biosensor bacterial strain Chromobacterium violaceum CV026. The results obtained indicate that the disinfectants studied have no anti-QS effect. The inhibition zones around the disc therefore only represent their antimicrobial effect.

Sour Cherry Pomace Valorization as a Bakery Fruit Filling: Chemical Composition, Bioactivity, Quality and Sensory Properties

Sour cherry pomace filling (SCPF) and commercial sour cherry filling (CSCF) produced on a semi-industrial scale were tested and compared in terms of food safety, chemical composition, bioactivity, quality, sensory properties and thermal stability. Both samples were safe for human consumption, thermally stable and there was a lack of syneresis. SCPF had a significantly higher fiber concentration (3.79 g/100 g) due to higher skin fraction and is considered a "source of fibers". The higher skin fraction in SCPF also resulted in a higher mineral quantity (Fe-3.83 mg/kg fw) in comparison to CSCF (Fe-2.87 mg/kg fw). Anthocyanins concentration was lower in SCPF (7.58 mg CGE/100 g fw), suggesting that a significant amount of anthocyanins was removed from SC skin during juice extraction. However, there was a lack of statistical differences in antioxidant activity between the two fillings. CSCF was more spreadable, not as firm and less sticky, with lower storage and loss modulus values than SCPF. However, both fillings exhibited acceptable rheological and textural behaviour for fruit fillings. According to the consumer pastry test, 28 participants preferred each pastry; thus, there was a lack of preference toward any of the tested samples. SCP could be used as a raw material for the bakery fruit fillings industry, which leads to the valorization of food industry by-products.

UHPLC-Triple-TOF-MS Characterization, Antioxidant, Antimicrobial and Antiproliferative Activity of Raspberry (Rubus idaeus L.) Seed Extracts

The primary aim of this experiment was to investigate the bioactivity potential and polyphenolic profile of defatted raspberry seeds (DRS) extracts from three varieties (Willamette, Meeker, and Polka) using the in vitro tests HPLC-DAD and UHPLC-Triple-TOF-MS. Extracts were obtained using ultrasound-assisted extraction (UAE) or hydrolysis. The antioxidant activity of the extracts was tested using 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic) cation (ABTS), and ferric reducing antioxidant power (FRAP) assays. Furthermore, the extracts were tested for antimicrobial activity using the disk diffusion method for four bacterial cultures (Staphylococcus aureus, Escherichia coli, Listeria monocytogenes, and Salmonella enterica subsp. enterica Enteritidis). In vitro antiproliferative activity was tested using cervical carcinoma (HeLa), breast adenocarcinoma (MCF7), and fetal lung (MRC-5) human cell lines. In total, 32 phenolic compounds were detected in DRS extracts. A small quantity of ellagic acid (EA) was in free form, while EA content increased after the hydrolysis process. The extracts from the Meeker variety exhibited the highest antioxidant activity, analyzed with DPPH and FRAP assays, while extracts from the Polka variety had the highest activity towards ABTS•⁺ radical scavenging activity. The UAE samples expressed higher antiproliferative activity in comparison to hydrolysis extracts. The results indicate that DRS extracts have certain bioactivity, and their use in the food, cosmetic, and pharmaceutical industries is recommended.

Chemical Composition, Antimicrobial Activity, and Withdrawal Period of Essential Oil-Based Pharmaceutical Formulation in Bovine Mastitis Treatment

Due to the emergence of antibiotic-resistant bacteria, the risk it represents to public health, and the possible consequences for animal health and welfare, there is an increasing focus on reducing antimicrobial usage (AMU) in animal husbandry. Therefore, a great interest in developing alternatives to AMU in livestock production is present worldwide. Recently, essential oils (EOs) have gained great attention as promising possibilities for the replacement of antibiotics. The current study aimed to test the potential of using a novel EO-based pharmaceutical formulation (Phyto-Bomat) in bovine mastitis treatment. The antibacterial activity was performed using the microdilution technique. Lactating dairy cows were treated with 15 mL of Phyto-Bomat in the inflamed quarter for 5 consecutive days in order to analyze blood and milk samples for thymol and carvacrol residues using gas chromatography and mass spectrometry (GC-MS). Antimicrobial activity expressed as the minimum inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) indicates that this formulation has the highest activity against Gram-positive strains. The dominant compounds in Phyto-Bomat were thymol and carvacrol, at 12.58 ± 1.23 mg/mL and 23.11 ± 2.31 mg/mL, respectively. The quantification of these two compounds in evaluated biological samples showed that 24 h after administration the concentration of thymol and carvacrol in milk samples was at the same level as before application. On the other hand, thymol and carvacrol were detectable in plasma samples even after 24 h post-treatment, with values ranging from 0.15-0.38 and 0.21-0.66 µg/mL, respectively. The tested formulation showed encouraging results of antibacterial activity against bovine mastitis pathogens, as well as the withdrawal period of dominant compounds, which implies that further testing regarding the bacteriological and clinical cure rates in clinical settings is needed.

Risk factors and the overall characterization of Yersinia enterocolitica as an initial model of pathogen surveillance in the pig production system in Serbia

A survey was undertaken to determine the overall prevalence of Yersinia enterocolitica in pigs of slaughter age and to characterize the isolates in relation to bio-serotype, the presence of virulence genes, genetic diversity, and antimicrobial resistance. Moreover, possible risk factors associated with Y. enterocolitica infection during the pre-harvested and harvested phase of pig production were studied. The overall Y. enterocolitica prevalence in the pigs was 10.4% (95% confidence interval, CI = 8.5-12.3%). The most common Y. enterocolitica bio-serotype was 4/O:3, accounting for 81.6% of investigated isolates. The pathogenicity of 63 Y. enterocolitica 4/O:3 isolates, originating from all infected farms, was confirmed by the presence of both the ail and ystA virulence-associated genes and the absence of ystB gene (100%). Characterization with PFGE of 63 confirmed Y. enterocolitica 4/O:3 isolates identified five different genotypes with shared identical genetic profiles (100% similarity) within each genotype. Isolates originating from farrow-to-finish farms were only resistant to ampicillin, while resistance to nalidixic acid, tetracycline, and chloramphenicol at fattening farms was also observed. Risk factors related to Y. enterocolitica pig infection include fattening farms (odds ratio, OR = 2.3, 95% CI = 1.4-3.8, P < 0.001), a 3-6 h lairage period (OR = 1.6, 95% CI = 1.0-2.6, P = 0.035) and winter season (OR = 3.8, 95% CI = 2.0-7.4, P < 0.001). In addition to the overall characterization of Y. enterocolitica isolates, identification of the main risks associated with infection allows better application of preventive measures to reduce the occurrence and distribution of Y. enterocolitica infection.

Antibacterial Potential of Allium ursinum Extract Prepared by the Green Extraction Method

The antimicrobial activity of Allium ursinum aqueous extract prepared using high pressure extraction was evaluated. Minimal inhibitory concentrations (MIC) and minimal bactericidal concentrations (MBC) of A. ursinum extract for six bacterial pathogens were determined using the broth macrodilution method. Although the A. ursinum extract was shown to be effective toward all investigated foodborne bacteria, its antimicrobial activity depended on its concentration and bacterial strain. Listeria monocytogenes was the most sensitive to antimicrobial activity of A. ursinum extract among all tested pathogens. Accordingly, the lowest MIC and MBC of A. ursinum extract were determined for L. monocytogenes (28 and 29 mg/mL). The tested extract showed a similar antimicrobial potential to other examined bacterial strains (Salmonella Enteritidis, Proteus hauseri, Enterococcus faecalis and two strains of Escherichia coli) with MIC and MBC values at concentrations of 29 and 30 mg/mL, respectively. The dependence of the antimicrobial activity of the A. ursinum extract on the level of contamination of tested pathogens was also observed. The increase in the contamination level caused an intense reduction in antibacterial potential of the A. ursinum extract. The composition of the A. ursinum extract was analyzed and found to be a good source of polyphenols and sulfur compounds. However, considering the applied extraction method and the HPLC analysis of bioactive compounds, the antimicrobial potential may be attributed more to polyphenol content. The obtained results that the extracts have shown toward food pathogens open the possibility of using the tested extracts as natural additives in a variety of food products.

Evaluation of the physicochemical, biochemical and microbiological characteristics of three Serbian traditional dry-fermented sausages

Three Serbian traditional dry-fermented sausages, Sremski kulen (S), Lemeški kulen (L) and Petrovačka kobasica (P), were compared for physicochemical, biochemical and microbiological properties, in order to provide complex overview of their quality and safety. The sausages were produced and analyzed within two production seasons in traditional practice. Water activity, color, texture and proximate composition varied significantly (P < 0.05), particularly due to moisture, protein and fat content, what indicated differences in basic formulation of raw sausage mixture, type of casing and some technological procedures. Based on the fatty acid profile the most favorable PUFA/SFA ratio was obtained in sausage P (0.68), while the obtained results for acid value (15.2-22.4 mg KOH/g lipid) and TBARS value (0.27-0.55 mg malondialdyde/kg) indicated low level of lipid degradation and oxidation in all samples. Regarding the microbial and biogenic amines (BA) analysis, positive outcome of this research is the total absence of all pathogenic microorganisms examined, while the registered levels of BA showed a great variability among the sausages. In particular, total BA content in L attained level that is approx. 50% higher than the recommended one. Hence, special care should be implemented regarding the future production and consumption of this type of sausage. Overall results of this study may be useful to define complete distinctive features of these sausages, to determine relations among them, as well as to improve some phases of traditional manufacturing process.

Preliminary Survey of Alternaria Toxins Reduction during Fermentation of Whole Wheat Dough

The aim of this study was to investigate the fate of the most common Alternaria toxins found in wheat-tenuazonic acid (TeA), alternariol (AOH), and alternariol monomethyl ether (AME) during sourdough processing. For this purpose, spiked whole wheat flour, 3% sourdough starter, 0.5% of baker's yeast, and 105% of water calculated on flour weight as a base were used as raw materials. Spiked whole wheat dough was fermented for 4 h, 8 h, 12 h, 24 h, and 48 h at 25 °C, and at each point the fermented dough samples were taken, frozen, lyophilized, grounded, and stored until further analysis. To study the effect of sourdough processing on TeA, AOH and AME content, the validated method of high-performance liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) for these mycotoxins was used. Mathematical models of Alternaria toxins reduction were developed in the form of Four Parameter Logistic Regression function. The maximum reduction of TeA, AOH, and AME levels was archived at 48 h of dough fermentation at 25 °C compared with dough after kneading (0 h). Under these conditions, a reduction of the toxin levels of 60.3 %, 41.5%, and 24.1% was observed for TeA, AOH, and AME, respectively.

Encapsulations of wild garlic (Allium ursinum L.) extract using spray congealing technology

The objective of this study was to incorporate wild garlic (A. ursinum) extract into microparticles (MPs) in order to protect its valuable active compounds and improve its oral bioavailability. For this purpose, spray congealing technology was applied and Gelucire 50/13 (Stearoyl polyoxyl-32 glycerides) was selected as MPs carrier. MPs were characterized in terms of yield, encapsulation efficiency and particle size. Differential scanning calorimetry (DSC) and Fourier-transform infrared spectroscopy (FT-IR) analysis of MPs showed the absence of chemical interactions between carrier and extract and suggested that spray congealing process did not modify nor degrade the encapsulated extract. The encapsulation into MPs led to an improvement of the extract dissolution performance as well as an enhancement in solubility of >18 fold compared to the pure extract. Additionally, MPs were stable over three months showing only a minor decrease in the content of active compounds (allicin and S-methyl methanethiosulfonate) and maintaining a good antimicrobial activity. Therefore, obtained results suggested that the encapsulation of A. ursinum extract in MPs by spray congealing is a promising approach to improve the biopharmaceutical properties of the extract, without affecting its antibacterial activity.