Occurrence of ochratoxin A before bottling in DOC and DOCG wines produced in Piedmont (Northern Italy)

Italy is one of the countries where ochratoxin A (OTA) contamination in wine poses more risks. Previous surveys on the occurrence of OTA have poorly considered north Italian wines. In this study, 1206 red and white DOC and DOCG wines produced in Piedmont (Northern Italy) from 2000 to 2007 have been analyzed for OTA level (0.116 μg l⁻¹) and incidence (68.0%). The monitoring – the widest per number of Italian wine samples considered – analyzed the OTA contamination of wines in tanks just before bottling. OTA level and incidence were significantly higher in red (0.121 μg l⁻¹, 69.4%) than in white (0.086 μg l⁻¹, 61.3%) wines. Among the white wines, the incidence was significantly lower in the Moscato wines (7.3%), due to the different wine processing. The differences in the mean OTA level in the three main grapevine varieties of red wines could be related to the harvest period. Among the Nebbiolo appellations, a reduction of the OTA level was noticed with increasing the wood aging period. A significant effect of the vintage year was also registered.     

ELISA and HPLC analysis of ochratoxin A in red wines of Croatia

Ochratoxin A (OTA) contaminates wine all round the world, and its consumption may significantly increase human exposure to this toxin. In this study, enzyme-linked immunosorbent assay (ELISA) and high-performance liquid chromatography (HPLC) for OTA analysis were tested on must and wine samples collected in Croatia. The results of ELISA and HPLC analysis of OTA in naturally contaminated red wines correlated well (r = 0.821), and the correlation was better at higher OTA concentrations. In contrast to HPLC, ELISA could not detect very low OTA concentrations. OTA concentrations in must (range 19–50 ng/l) were higher than in the wines (range 0–21 ng/l). No must samples showed the presence of Aspergillus carbonarius, which is a common OTA-producing mould affecting grapes.     

High performance liquid chromatography analysis of phenolic substances in Greek wines

Eleven samples of commercially available Greek wines were analyzed in order to determine the phenolic content. For the analysis, reversed phase-high performance liquid chromatography (RP-HPLC) coupled with diode array detection was used. The most abundant phenolic substance detected was (+)-catechin (11.8–40 mg l⁻¹). Red wines contained more phenolic substances than white ones. The effect of aging in oak wood barrels on phenolics was also investigated. Specific types of Greek white wines, “retsina”, were also analyzed. Pitch, which is added to such types of wines, contributes significantly to the increased amount of phenolic compounds present in the wine.     

Evaluation of acetaldehyde and methanol in greek traditional alcoholic beverages from varietal fermented grape pomaces (Vitis vinifera L.)

Traditional alcoholic beverages produced from fermented grape pomaces (Vitis vinifera L.) are very popular in Greece and many other Mediterranean countries and some times consumed in large amounts daily. Acetaldehyde and methanol are two important toxic volatile compounds in wine and alcoholic beverages, that formed during grape pomace fermentation. The EU regulation 1576/89 fixed common analytical composition limits for those volatiles (1000 g/hL AA for methanol and 73–500 g/hl AA for acetaldehyde.In this study the two major toxic volatile compounds, methanol and acetaldehyde, were determined in varietal grape pomace distillates. Twelve of the most popular Greek grape varieties, six white and six red, were used for the production of grape pomace distillates that were collected in ten equal volume fractions. Grape pomace distillates were analysed by gas chromatography with f1ame ionization detector (FID) using pentanol-3 as an internal standard. The concentrations of these volatiles as well as their changes during distillation were measured. It should be also pointed out that the two toxic compound, acetaldehyde and methanol was detected far below the acceptable legal limits. The results may be useful for risk assessment of acetaldehyde and methanol.     

Aflatoxin M1 contamination in dairy products marketed in Iran during winter and summer

In the present study, 298 dairy product samples consisting of pasteurized milk (91 samples), yoghurt (68 samples), white cheese (72 samples), butter (31 samples) and ice cream (36 samples) collected from popular markets in four large Iranian cities were examined for aflatoxin M₁ (AFM₁) by thin layer chromatography (TLC) technique. The toxin was detected in 66 (72.5%) pasteurized milk samples (mean: 0.052 μg/l; range: 0.013–0.250 μg/l), 45 (66.1%) yoghurt samples (mean: 0.032 μg/kg; range: 0.015–0.119 μg/kg), 59 (81.9%) white cheese samples (mean: 0.297 μg/kg; range: 0.030–1.200 μg/kg), 8 (25.8%) butter samples (mean: 0.005 μg/kg; range: 0.013–0.026 μg/kg) and 25 (69.4%) ice cream samples (mean: 0.041 μg/kg; range: 0.015–0.132 μg/kg). The concentration of AFM₁ in 36.2%, 20.6%, 30.5%, 9.6% and 27.7% of pasteurized milk, yoghurt, white cheese, butter and ice cream samples, respectively, were higher than Iranian national standard limits. Levels of AFM₁ in samples of pasteurized milk, yoghurt, butter and ice cream collected in winter were significantly higher (P < 0.05) than those collected in summer. In the case of white cheese, level of AFM₁ was higher in winter than in summer, but the difference was not statistically significant (P > 0.05). The results indicated that the contamination of the dairy products in such a level could be a serious public health problem at the moment.     

The development of an activated carbon from cherry stones and its use in the removal of ochratoxin A from red wine

The ability of activated carbon (AC) prepared from cherry stones (CS) by activation with H₃PO₄, ZnCl₂ or KOH to remove ochratoxin A (OTA) from two Italian red wines has been studied. AC was characterized in terms of texture and surface chemistry. OTA was analyzed by reversed-phase high-performance liquid chromatrography, using a fluorescence detector. The content of OTA in the starting wines is 7.38 and 2.36 μg/L. The adsorption of OTA is high only for one AC, which was prepared by KOH activation at 900 °C, using the 3:1 KOH:CS impregnation ratio. It possesses a large apparent surface area (S_BET = 1620 m²/g) and a high volume of large size macropores (1.84 cm³/g). It also contains narrow mesopores and intermediate size and wide micropores. Its content of acidic oxygen surface groups is low, whereas the content of basic groups is high (2.62 meq/g). The treatment of the wines with such an AC results in a decrease of the initial OTA content of more than 50%. However, the changes produced in the total polyphenolic index, color intensity, and hue are small (i.e. ～8%, ～5.5% and ～1.2%, respectively).     

Pesticide residues in grapes and during vinification process

Pesticide residues in vinification process of two white and two red grapevine varieties were monitored during the 2007 vintage. Crushed grapes, cake, must, lees and wine were sampled during the vinification process. Additionally, grapes were sampled during the ripening process. All samples were taken in triplicate and analyzed for the presence of 117 pesticides. The pesticide residues were determined by three validated internal analytical methods: the multi-residual GC-MS method (71 pesticides), the multi-residual LC-MS-MS method (45 pesticides) and GC-MS method for the determination of dithiocarbamates (the sum of their concentrations is given as a concentration of carbon disulfide). Boscalid and phosalone were the most persistent pesticides in grapes during ripening. The concentrations of pesticide residues in must and wine were significantly diminished through separations during the solid and liquid phases of the vinification process, particularly the pressing of crushed grapes and wine racking after alcoholic fermentation. The pesticides detected throughout the vinification process were boscalid, cyprodinil, dimethomorph, fenhexamid, metalaxyl and procymidone and their concentrations in the wines were 0.01–0.02, 0.04, 0.01–0.08, 0.12–0.13, 0.09–0.11 and 0.07–0.13 mg L⁻¹ respectively.     

Essential oils composition,antioxidant and antimicrobial activity of the leaves and flowers of Chaerophyllum macropodum Boiss

This study reports the essential oils chemical composition and in vitro antioxidant and antimicrobial potentials of the leaves and flowers of Chaerophyllum macropodum. GC and GC/MS analysis of the plant essential oils led to the identification of 49 components making 98.3–99.4% of its oils. The main constituents of the essential oils were trans-β-farnesene, trans-β-ocimene, β-pinene, limonene, spathulenol and myrcene constituting 49.6–73.1% of the oils. The extracts from the leaves and flowers showed moderate antioxidant activities in 1,1-diphenyl-2-picrylhydrazyl (DPPH) test (IC₅₀ values = 196.8 and 167.1 μg/ml respectively) and β-carotene/linoleic acid assay (inhibitions percentages = 69.9% and 62.7% respectively), but the essential oils were almost inactive in these tests. On the other hand, only the essential oils of the plant showed considerable antimicrobial activity against most of the tested microorganisms.     

HPLC determination for prostaglandins from seaweed Gracilaria gigas

Seaweed (Gracilaria gigas) is an edible red alga and occasionally induces food poisoning cases. Prostaglandin E₂ (PGE₂) has been reported to be possible causative agent. In this study, a simple, sensitive, rapid and accurate HPLC method was developed for quantifying prostaglandins in seaweed. The mobile phase was gradient acetonitrile (35–60%) and 0.017 M phosphoric acid at flow rate of 1 mL/min within 30 min. The standard curves of prostaglandins were extremely linear (R² > 0.999) with low correlation coefficients (less than 4.7) in the range of 5–50 μg/mL. To obtain maximum prostaglandins amount, the optimal ratio of seaweed (wet weight) to arachidonic acid was 10 g:2 mg and oxygen was needed in reaction.     

Effect of post-harvest practices on flavonoid content of red and white onion cultivars

Onions are major sources of flavonoids in the human diet. However, little information is available regarding the effects of long-storage or exposure to specific stress conditions on flavonoids content of onions. The aim of this work was to assess the effect of different post-harvest treatments on the flavonoid composition of two Portuguese landrace varieties of onions (‘Branca da Póvoa’ and ‘Vermelha da Póvoa’). The evolution of the content of some major flavonols and anthocyanins was measured in red and white onion bulbs (from 2005 and 2006 harvests) during 7 months of storage, under refrigerated and under traditional bulk storage in the field. Total flavonols increased up to 64% after 6 or 7 months of storage. This increase was especially important during the first 3 months of storage (58% increase). In red onions, with the largest concentrations in flavonols, bulbs stored in the field reached higher levels of flavonoids (64% maximum) than refrigerated onions (40% maximum). For red onions, the increase after 6-months storage usually has place when the flavonol post-harvest levels are low (40–64% increase), whereas for white onions the increase after 6-months storage is important for onions with higher levels after harvest (44–60% increase). These results suggest that storage at fluctuating ambient temperatures can positively affect flavonol metabolism, while keeping the flavonols profile. There were no significant modifications of the total levels of anthocyanin pigments after 6 months of storage of red bulbs, but after 7 months total anthocyanin content was reduced between 40% and 60%. Post-harvest UV (40 kJ/m², 1 week storage) and ethylene (100 μL/L for 24 h, 2 months storage) treatments did only affect the flavonol content of the edible portion of onions with a profitable increase.     

Biogenic amines content,histamine-forming bacteria and adulteration of bonito in tuna candy products

Thirty-four tuna candy products sold in retail markets and supermarkets in Taiwan were purchased and tested to determine the biogenic amine, histamine-forming bacteria, and adulteration of bonito meat. The levels of pH value, water activity (Aw), water content, total volatile basic nitrogen (TVBN), aerobic plate count (APC) and total coliform (TC) in all samples ranged from 5.3 to 6.1, 0.47 to 0.65, 7.37% to 17.32%, 12.1 to 54.6 mg/100 g, <1 to 6.2 log CFU/g and <3 to 1700 MPN/g, respectively. None of these sample contained Escherichia coli. The average content of various biogenic amines in all tested samples was less than 1.0 mg/100 g. Four histamine-producing bacterial strains isolated from tested samples produced 1.02–1.74 ppm of histamine in trypticase soy broth supplemented with 1.0% l-histidine (TSBH) after incubation at 35 °C for 24 h. Assay of multiplex polymerase chain reaction (PCR) revealed that adulteration rate of bonito meat was 26.5% (9/34) in tuna candy samples. Tuna species in tuna candy samples was identified as Thunnus albacares for 29 samples (85.3%), Thunnus alalunga for four samples (11.8%) and Thunnus obesus for one sample (2.9%) by polymerase chain reaction–restriction fragment length polymorphism (PCR–RFLP).     

Aflatoxin M1 in raw milk in Croatia

In this study the levels of aflatoxin M₁ (AFM₁) of 61 milk samples delivered from small milking farms were determined in January, February, March and April (winter–spring season), and June, July and September (summer–autumn season) of 2009. The AFM₁ concentration was determined by competitive enzyme-immunoassay method. The maximum mean concentrations of AFM₁ recorded in winter–spring season were in the range of 35.8–58.6 ng/l and in summer–autumn season in the range of 11.6–14.9 ng/l. The AFM₁ levels determined in January, February, March and April were significantly higher in accordance with concentration of AFM₁ in June, July and September (P < 0.05 to P < 0.0001, respectively). Also, there was significant difference (P < 0.0001) between the mean concentrations of AFM₁ in samples taken all together in winter–spring and summer–autumn season. Only in one sample delivered in February the level of AFM₁ was higher than the maximum tolerance limit (50 ng/l). Therefore, it was concluded that in 98.4% of milk samples in Croatia the levels of AFM₁ were below maximum tolerance level accepted by the European Union.     

Methanol contents of Turkish varietal wines and effect of processing

Methanol levels of Turkish varietal wines obtained from different representative viticultural regions were determined and the effect of maceration time and pectolytic enzyme treatments on the methanol levels of the red wines were investigated. 164 wine samples (60 white, 4 rosé, 100 red) were analysed by gas chromatography–flame ionisation detector (GC–FID). Methanol levels ranged from 30.5 to 121.4 mg/l in white wines, 62.5 to 84.6 mg/l in rosé, and 61.0 to 207.0 mg/l in red wines. The highest level was found in Sultaniye among the white wines, and in Öküzgözü among the red wines. Methanol content of red wines increased with maceration time. Pectolytic enzyme treatments produced significantly higher methanol levels than the control wine. All the results show that methanol levels of Turkish wines are under the maximum acceptable limits of International Office of Vine and Wine (OIV) and do not represent a risk to consumer health.     

Histamine level and histamine-forming bacteria in dried fish products sold in Penghu Island of Taiwan

Forty-six dried fish products sold in retail markets in Penghu Islands, Taiwan were purchased and tested to determine the occurrence of histamine and histamine-forming bacteria. The levels of pH, salt content, water content, water activity (Aw), total volatile basic nitrogen (TVBN), aerobic plate count (APC), Escherichia coli and total coliform (TC) in all samples ranged from 5.60 to 7.57, 1.8% to 27.1%, 19.32% to 61.90%, 0.63 to 0.92, 10.41 to 168.56 mg/100 g, 3.18 to 9.28 log CFU/g, <3 to 210 MPN/g and <3 to >1100 MPN/g, respectively. There had 30.4% of the tested dried fish products to contain histamine level more than 5 mg/100 g of FDA guideline for scombroid fish and/or product. Among them, all of the nine samples of Selariodes leptolepis had the highest histamine content of 6.31–47.90 mg/100 g. Thirteen histamine-producing bacterial strains isolated from tested samples produced 8.7–531.2 ppm of histamine in trypticase soy broth supplemented with 1.0% l-histidine (TSBH). Among these histamine-producing bacteria, Enterobacter aerogenes (one strain) isolated from S. leptolepis sample was proven to be a prolific histamine-former.     

Antimicrobial activity of phenolic compounds of wine against Campylobacter jejuni

Campylobacter jejuni is a food pathogen which causes gastrointestinal conditions with an ever-increasing incidence at a global level. The antimicrobial power of wine and its components has been studied. Wines having 11.5% ethanol significantly reduced the viability of C. jejuni when they were diluted to 25% in water. The microbicidal power of red wine was higher than that of white wine. While pH does not seem to affect the viability of this pathogen, different phenolic compounds have an effect on it when tested at concentrations from 0 to 1000 mg/L. Gallic acid and p-hydroxybenzoic acid reduced the viability of C. jejuni at concentrations as low as 1 mg/L, but quercetin and catechin did not even affect it at concentrations of 1000 mg/L. Methyl gallate, epicatechin, synaptic acid, vanillic acid, and caffeic acid were microbicidal at concentrations starting at 10 mg/L. Tryptophol, ferulic acid, and cumaric acid were effective starting at 100 mg/L. According to this, wine constitutes an adverse environment for the survival of this pathogen. Furthermore, it would be interesting to study the possible use of phenolic compounds in wine as an alternative to the use of antimicrobial growth promoters against these bacteria in broilers.     

Effect of catechin and ferulic acid on melanosis and quality of Pacific white shrimp subjected to prior freeze–thawing during refrigerated storage

Melanosis of Pacific white shrimp (Litopenaeus vannamei) subjected to freeze–thawing with different thawing methods and various cycles were monitored during subsequent refrigerated storage (4 °C) up to 4 days. Melanosis score was lower in Pacific white shrimp thawed at 4 °C, compared with that found in samples thawed at room temperature or using tap water. Polyphenol oxidase (PPO) activity increased as freeze–thaw cycles increased (P < 0.05). Enhanced PPO activity was most likely associated with increased melanosis. Pacific white shrimp treated with catechin (0.05%, 0.1% and 0.2% (w/v)) or ferulic acid (1%, 2% and 3% (w/v)) and subjected to freeze–thawing with various cycles showed the retarded melanosis during the subsequent refrigerated storage of 4 days, compared with the control (P < 0.05). Treatment of shrimp with both phenolic compounds could impede the growth of psychrophilic bacteria and the spoilage as evidenced by the lowered psychrophilic bacteria count and total volatile base content (TVB). Sample treated with 0.2% catechin or 3% ferulic acid also exhibited the retarded lipid oxidation during the subsequent refrigerated storage, compared with the control (P < 0.05). Thus, either catechin or ferulic acid could be used as the potential additive to lower melanosis of shrimp with prior freeze–thawing.     

Changes in the concentration of aflatoxin M1 during manufacture and storage of White Pickled cheese

In this study White Pickled cheese was produced from cow’s milk contaminated artificially with aflatoxin M₁ (AFM1) at two different levels, 1.5 and 3.5 μg/kg (ppb), and the effects of process stages on the AFM1 contents were investigated. Pasteurization at 72 °C for 2 min caused losses of AFM1 about 12% and 9%, respectively, in milk contaminated with 1.5 μg/kg AFM1, and 3.5 μg/l AFM1. These losses were found to be statistically significant (P < 0.01). After the cheese production, about 56% and 59% of total AFM1 remained in cheese–curd while about 32% of total AFM1 transferred to the whey for both 1.5 μg/kg and 3.5 μg/kg AFM1 contaminated milk. After 3-month storage in brine, AFM1 content of cheeses produced from 1.5 and 3.5 μg/kg AFM1 contaminated milks decreased by 2.9% and 2.8%, respectively. Changes in AFM1 content of cheese samples were found statistically insignificant (P > 0.05 and P > 0.01) for 3-month storage periods.     

Histamine contents and histamine-forming bacteria in sufu products in Taiwan

Twelve white and ten brown sufu products sold in the supermarkets in southern Taiwan were purchased and tested to determine the occurrence of histamine and histamine-forming bacteria. The levels of pH, salt content, and aerobic plate count (APC) in all samples ranged from 4.6 to 6.6, 6.2% to 12.0%, and 3.0 to 7.9 log CFU/g, respectively. None of these samples contained total coliform and Escherichia coli. Although the average content for each of the nine biogenic amines in all samples was less than 5 mg/100 g, only one brown sufu sample had histamine content (15.8 mg/100 g) greater than the 5.0 mg/100 g allowable limit suggested by the US Food and Drug Administration. Two histamine-producing bacterial strains capable of producing 1.33 mg/100 ml and 1.34 mg/100 ml of histamine in trypticase soy broth (TSB) supplemented with 1.0% l-histidine (TSBH) were identified as Bacillus subtilis by 16S rDNA sequencing with PCR amplification.     

Prediction of total antioxidant capacity of red wine by Fourier transform infrared spectroscopy

Fourier transform infrared (FTIR) spectroscopy provides rapid and nondestructive analysis of wine, with almost no sample preparation. Aim of this study was to use FTIR measurement for the prediction of red wine total antioxidant capacity (TAC). Partial-least squares (PLS) regression was chosen for the evaluation of FTIR spectra. Plot of the full cross-validated PLS predicted TAC values showed a good correlation (r = 0.85), the slope of 0.74 and the prediction error provided by the PLS model was consistent with the uncertainty derived from the reference method. In conclusion, FTIR spectroscopy is a promising technique to rapidly provide information on TAC of red wines and has a high potential to be implemented for the rapid screening of several TAC methods concurrently.     

Pesticide residues and microbiological quality of bottled wines

In the study we determined the pesticide residues and microbiological quality of bottled wines. Pesticide residues in wine were analysed using the multiresidual method with GC–MS, the multiresidual method with LC–MS–MS and the method for determination of dithiocarbamate residues with GC–MS. Furthermore, the effect of bentonite and the combined fining agent on the concentration of boscalid in wine was tested. The microbiological analysis was performed using membrane filtration. Nine pesticide residues were determined in the samples. More than 50% of wines belonged to the category of wines with only up to two pesticide residues. The most frequently determined pesticide in wines was boscalid (76% of samples) followed by fenhexamid (44%). The highest concentrations of pesticide residues in wines were determined for cyprodinil (0.44 mg/L) and fludioxonil (0.21 mg/L). The combined fining agent was more efficient in lowering the concentration of boscalid in wine if compared with bentonite. The results of microbiological quality indicate that no less than one quarter of bottled wines on our store shelves is microbiologically unstable.