Fungicides in red wines produced in South America

Occurrence and impact of carbendazim and hymexazol residues on yeast growth and ochratoxin A contamination during wine production

BACKGROUND

Grapes are highly vulnerable to infection by carbon black aspergilli, which produce ochratoxin A (OTA), a mycotoxin. Carbendazim and hymexazol are widely applied to control grape diseases. Howerver, fungicides, toxigenic fungi, and OTA can be transferred from grapes to wine causing potential safety issues. The impact of these residues on fungal populations and OTA during vinification are currently unclear. Here we investigated the effects of carbendazim and hymexazol on the viability of Aspergillus carbonarius and OTA contamination during an indoor wine-processing experiment.

RESULTS

The population size of A. carbonarius substantially increased at 24 h followed by a significantly decreased at 72 h after destemming and crushing. However, carbendazim and hymexazol notably inhibited the growth of A. carbonarius in must samples. In addition, yeast growth was substantially deleyed by carbendazim, hymexazol, and OTA during the first 3 days in compared with the control. Carbendazim, hymexazol, and OTA residues declined over time, and the processing factors (PFs) for carbendazim and hymexazol throughout vinification were 0.164, 0.074, and 0.185-0.476, respectively. Carbendazim and hymexazol each reduced OTA concentrations. However, there was no significant difference after 48 h. Addition of carbendazim or hymexazol significantly reduced the level of A. carbonarius but had no significant effect on the final concentration of OTA in mature wine.

CONCLUSION

The wine-making process can reduce the residues of OTA, carbendazim, and hymexazol in grapes, but it is recommended that grapes chosen to make wine should be free of A. carbonarius contamination. © 2023 Society of Chemical Industry.

Commercial yerba mate (Ilex paraguariensis) produced in South America: Determination of dithiocarbamate residues by gas chromatography-mass spectrometry

This work presents an easy and quick miniaturized procedure for the analysis of dithiocarbamates fungicides (DTC), by GC-MS, in yerba mate, an important product in South America. The sample amount, the volume of extracting solvent and acid solution, and the time of hot bath shaking were minimized. A clean-up procedure based on PSA, GCB and MgSO4 was studied in order to improve analytical signal and reduce GC-MS system damage. Blank yerba mate samples were spiked with thiram at equivalent CS₂ concentrations of 0.1, 0.3, 0.5 and 1 mg kg^-1. The validated method at least 2 times faster than the traditional method and was according to the latest European guidelines for pesticide residue analysis. Linearity, limits of detection and quantification, matrix effects, trueness and precision were assessed. Sixty-five commercialized samples from southern Brazil and Argentina were analyzed; 14% of samples presented CS₂ concentration greater than LOQ (0.1 mg kg^-1).

Impact of chiral tebuconazole on the flavor components and color attributes of Merlot and Cabernet Sauvignon wines at the enantiomeric level

The impact of chiral tebuconazole on the flavor and appearance of Merlot and Cabernet Sauvignon wines were systematically studied. Gas chromatography-ion mobility spectrometry and headspace-solid phase microextraction coupled with gas chromatography mass spectrometry qualitatively and quantitatively identified the flavor components, and a photographic colorimeter was used for color attribute analysis. Tebuconazole enantiomers had different effects on the flavor and appearance of young wines, especially R-tebuconazole. The flavor differences were mainly manifested in fruity and floral characteristics of the wine due to changes in the concentrations of acids, alcohols, and esters; R-tebuconazole alters the concentrations of key flavor compounds to the greatest extent. Tebuconazole treatment changes the color of young wines, with the final red shade of wine being control group > rac-tebuconazole ≥ S-tebuconazole > R-tebuconazole. Since chiral tebuconazole negatively alters wine, grapes treated with chiral pesticides should be subject to stricter quality control during processing.

Combined Developmental Toxicity of the Pesticides Difenoconazole and Dimethomorph on Embryonic Zebrafish

Difenoconazole (DIF) and dimethomorph (DIM) are widely used pesticides frequently detected together in environmental samples, so the deleterious effects of combined exposure warrant detailed examination. In this study, the individual and combined effects of DIM and DIF on conventional developmental parameters (hatching rate, deformity rate, lethality) and gene expression were measured in embryonic zebrafish. Both DIF and DIM interfered with normal zebrafish embryo development, and the most sensitive toxicity index for both was 96 h post-fertilization (hpf) deformity rate (BMDL₁₀ values of 0.30 and 1.10 mg/L, respectively). The combination of DIF and DIM had mainly synergistic deleterious effects on 96 hpf deformity and mortality rates. Transcriptome analysis showed that these compounds markedly downregulated expression of mcm family genes, cdk1, and cdc20, thereby potentially disrupting DNA replication and cell cycle progression. Enhanced surveillance for this pesticide combination is recommended as simultaneous environmental exposure may be substantially more harmful than exposure to either compound alone.

Clean-up Strategy for Dithiocarbamate Fungicide Determination in Soybean by GC-ITD-MS and GC-PFPD: Method Development and Validation

Food matrices consist of many components with different physical and chemical properties that may influence instrumental robustness. The soybean contains fatty coextractives which may have a deleterious effect on the gas chromatography (GC) system. In this study, the efficiencies of PSA, C18OH, C18, silica, aluminum oxide, and Florisil, as dSPE clean-up sorbents, were evaluated by the high-performance liquid chromatography (HPLC) diode-array detector and evaporative light-scattering detector analysis. The dithiocarbamates in soybean samples are determined as CS2 using acidic hydrolysis and isooctane partitioning, followed by GC-PFPD and GC-ITD-MS analyses. The linearity of the analytical curves, the instrument limit of detection matrix effects, the trueness and precision, and the method limit of quantification (LOQ) were assessed in the validation study. Milled soybean was spiked with thiram solution at three concentration levels (corresponding to 0.05, 0.1, and 0.5 mg CS2 kg-1) for recovery determination. Silica appeared to be an effective and cheap sorbent to remove coextracted matrix components without causing any CS2 losses. Recoveries were in the range of 68-91%, with relative standard deviations ≤ 8.7%. The method LOQ was 0.05 mg CS2 kg-1, and both GC-ITD-MS and GC-PFPD systems appeared to be appropriate and complementary to determine dithiocarbamate residues in soybean extracts.

Plant Fibers in Comparison with Other Fining Agents for the Reduction of Pesticide Residues and the Effect on the Volatile Profile of Austrian White and Red Wines

Pesticide residues in Austrian wines have so far been poorly documented. In 250 wines, 33 grape musts and 45 musts in fermentation, no limit values were exceeded, but in some cases high levels (>0.100 mg/L) of single residues were found, meaning that a reduction of these levels before bottling could make sense. In the course of this study, a white and a red wine were spiked with a mix of 23 pesticide residues from the group of fungicides (including botryticides), herbicides and insecticides. The influence of the following treatments on residue concentrations and volatile profiles were investigated: two activated charcoal products, a bentonite clay, two commercial mixed fining agents made of bentonite and charcoal, two yeast cell wall products, and a plant fiber-based novel filter additive. The results of this study show that all the agents tested reduced both residues and volatile compounds in wine, with activated charcoal having the strongest effect and bentonite the weakest. The mixed agents and yeast wall products showed less aroma losses than charcoal products, but also lower residue reduction. Plant fibers showed good reduction of pesticides with moderate aroma damage, but these results need to be confirmed under practical conditions.

Colonization of Aspergillus carbonarius and accumulation of ochratoxin A in Vitis vinifera, Vitis labrusca, and hybrid grapes - research on the most promising alternatives for organic viticulture

BACKGROUND

Aspergillus carbonarius has been identified as one of the main fungi that produce ochratoxin A (OTA) in grapes. This nephrotoxic mycotoxin has been legislated against in several countries and is a major concern for viticulture. Knowledge of resistance to, or susceptibility to, colonization by A. carbonarius may be useful in selecting the most promising cultivars for organic agriculture and could help in preventing fungal contamination in vineyards. This study aimed to evaluate the colonization potential and the capacity to produce OTA by A. carbonarius in Vitis vinifera, V. labrusca, and hybrid grapes. The correlation between OTA levels and grape berry characteristics was also analyzed.

RESULTS

The OTA content was only strongly correlated with the thickness and hardness of the grape skins. The correlation between OTA levels and these parameters was negative (grapes with the least thickness and hardness had the highest OTA levels). Vitis vinifera grapes were more susceptible to A. carbonarius than V. labrusca and hybrid grapes at both 25 and 4 °C. Chardonnay (V. vinifera) grapes showed the highest levels of OTA, followed by Merlot, Cabernet Sauvignon, Tannat, and Moscato Branco. Italia grapes were the exceptions among V. vinifera cultivars, since they showed similar thickness, hardness, and fungal resistance as the V. labrusca and hybrid grapes.

CONCLUSION

The highest resistance to A. carbonarius was observed in the following grapes: hybrids (BRS Lorena and BRS Violeta), V. labrusca (Isabel and Bordo), and V. vinifera (Italia). These cultivars can be prioritized in the implementation of organic viticulture. © 2020 Society of Chemical Industry.

Occurrence and impact of fungicides residues on fermentation during wine production- A review

Continuous fungicide spraying is required to eliminate fungal pathogens on grapes. However, this practice is associated with several risks, including contamination and environmental imbalance, as well as toxicity to operators and the induction of resistance in pathogens. In addition, a strong correlation has been reported between the presence of fungicides and the occurrence of issues during alcoholic fermentation, resulting in negative impacts on the sensory quality of the final products. Numerous studies have evaluated residue concentrations of phytosanitary products in grapes, juices, and wines, and a significant number of studies have assessed the impact of different agrochemicals on bioprocesses. However, a review compiling the key results of these studies is currently lacking. This review incorporates results obtained in the last decade from research on the presence of fungicide residues, including azoxystrobin, boscalid, captan, copper, fenhexamid, folpet, pyraclostrobin, pyrimethanil and tebuconazole, and their effects on fermentation kinetics. Practical solutions to mitigate these problems, both in vineyards and industry, are also presented and discussed. This review highlights the constant high fungicidal agent concentrations (greater than 1 or 2 mg L^-1) used throughout the winemaking process, with the impact of residues being of particular concern, especially with regard to their effect on yeast activity and the fermentation process. Thus, the adoption of methodologies that allow winemakers to control and trace these residues is an important step in avoiding or reducing fermentation problems throughout the winemaking process.[Figure: see text].

Sperm quality of rats exposed to difenoconazole using classical parameters and surface-enhanced Raman scattering: classification performance by machine learning methods

Difenoconazole is a fungicide extensively used in agriculture. The aim of this study was to evaluate the effects of difenoconazole fungicide on the sperm quality of rats. Wistar rats were divided into four groups: control and exposed to 5 (D5), 10 (D10), or 50 mg^-1 kg bw^-1day (D50) of difenoconazole for 30 days, by gavage. Classical sperm parameters and surface-enhanced Raman scattering (SERS) were performed. Progressive motility, acrosomal integrity, and percentage of morphologically normal spermatozoa were reduced in the D10 and D50 groups in comparison with the control group. Sperm viability was reduced only in the D50 group. Sperm number in the testis and caput/corpus epididymis and daily sperm production were reduced in the three exposed groups. SERS measurements showed changes in the spectra of spermatozoa from D50 group, suggesting DNA damage. In addition, machine learning (ML) methods were used to evaluate the performance of three classification algorithms (artificial neural network-ANN, K-nearest neighbors-K-NN, and support vector machine-SVM) in the identification task of the groups exposed to difenoconazole. The results obtained by ML algorithms were very promising with accuracy ≥ 90% and validated the hypothesis of the exposure to difenoconazole reduces sperm quality. In conclusion, exposure of rats to different doses of the fungicide difenoconazole may impair sperm quality, with a recognizable classification pattern of exposure groups.