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.     

Fast determination of principal volatile compounds in distilled spirits

A fast determination of principal volatile compounds (acetaldehyde, ethyl acetate, acetal, methanol, butan-2-ol, butan-1-ol and higher alcohols) by direct inject of the spirit drink has been developed. At a total analysis time of 23 min were quantified others 23 additional volatile compounds like ethyl esters, acetates higher alcohols, 1-hexanol, carbonyl compounds and others, responsible for the quality evaluation of the distillate. These compounds are very important for analysis of fermentation conditions, storage techniques and the quality control of the distillation process. The proposed method has been validated with r² values from 0.9988 to 0.9999 with limits of detection varied between 0.003 mg/L for isobutyraldehyde and 0.076 mg/L for diethyl succinate and acceptable reproducibility. The developed method was successfully applied to different samples of grape pomace protected by Specific Denomination “Orujo de Galicia”.     

Disinfecting efficacy of a plastic container covered with photocatalyst for postharvest

The simplification of the cleaning process of plastic containers used in the storage and/or distribution of fruits or vegetables is important. We coated a plastic container with an apatite-coated titanium dioxide photocatalyst (TiO₂–Ap container), and examined its disinfecting efficacy under UV irradiation from black light. The disinfecting efficacy of the TiO₂–Ap container on diluted drops evaporated from spinach (suspension) was examined. Changes in the microbial populations of the total aerobic bacteria, coliform bacteria, and moulds and yeasts in the TiO₂–Ap container were assayed at 25 °C for 24 h (UV-A intensity of 0.2 and 0.4 mW cm⁻²). The results showed that all of the microbial populations in the TiO₂–Ap container decreased with irradiation time and then reduced to uncountable levels. It was found that the increase in UV-A intensity enhanced the disinfecting efficacy.     

Inactivation of Listeria monocytogenes inoculated on disposable plastic tray,aluminum foil,and paper cup by atmospheric pressure plasma

The objective of this study was to investigate the effect of atmospheric pressure plasma (APP) on Listeria monocytogenes inoculated onto disposable food containers including disposable plastic trays, aluminum foil, and paper cups. The parameters considered in APP processing were input power (75, 100, 125, and 150 W) and exposure time (60, 90, and 120 s). The bacterial reduction in the disposable plastic trays, aluminum foil, and paper cups was associated with increased input power and exposure time of APP. The D₁₀ values were calculated as 49.3, 47.7, 36.2, and 17.9 s in disposable plastic trays, 133, 111, 76.9, and 31.6 s in aluminum foil and 526, 65.8, 51.8, and 41.7 s in paper cups at 75, 100, 125, and 150 W of input power, respectively. There were no viable cells detected after 90 and 120 s of APP treatment at 150 W in disposable plastic trays. However, only three decimal reductions of viable cells were achieved in aluminum foil and paper cups at 150 W for 120 s. These results demonstrate that APP treatment is effective for inactivation of L. monocytogenes and applicable for disposable food containers. However, the type of material is crucial and appropriate treatment conditions should be considered for achieving satisfactory inactivation level.     

Quality differences of whole ungutted sea bream (Sparus aurata) and sea bass (Dicentrarchus labrax) while stored in ice

The aim of this study is to determine the quality changes in whole ungutted sea bass and sea bream while stored in ice. Changes in chemical quality were determined by using pH, total volatile basic nitrogen (TVB-N, mg N/100 g), trimethylamine (TMA-N, mg/100 g), thiobarbituric acid (TBA, mg malonaldehyde/kg), water activity (a_w), color measurement, and sensory analysis. Changes in microbiological quality were determined by using the analysis of total viable mesophilic and psychrophilic bacterial counts. Result of this study indicated that the shelf life of sea bass and sea bream stored in ice as determined by overall acceptability sensory scores and microbiological data was 15 days.     

Exposure to ethyl carbamate in alcohol-drinking and nondrinking adults and its reduction by simple charcoal filtration

The risk of exposure to ethyl carbamate from the consumption of kimchi, soy sauce, and alcoholic beverages was assessed in alcohol-drinking and nondrinking adults. An alcohol-drinking adult obtains 5.6–9.2 ng/kg bw/day of ethyl carbamate through the addition of kimchi and soy sauce, while a nondrinking adult receives 3.3–4.0 ng/kg bw/day via kimchi and soy sauce alone. The average excess cancer risk of an alcohol-drinking adult (3.9 × 10^?7) was also twice higher than that of an adult who does not drink (1.9 × 10^?7). We achieved a maximum of 47% and 45% removal of the ethyl carbamate present in diluted spirits and soy sauce, respectively, through a simple charcoal filtration process. This resulted in a reduction of the average daily intakes of ethyl carbamate through diluted spirits and soy sauce from 1.7 and 2.2 ng/kg bw/day to 0.9 and 1.2 ng/kg bw/day, respectively.     

Formation and diffusion mechanism of histamine in the muscle of tuna fish

This study investigates the formation and accumulation of histamine in the fresh meat of tuna fish. Under sterilized conditions, histamine was not detected in the muscles of Thunnus obesus (T. obesus) stored at 20 °C and 25 °C for 72 h (data not shown). And histamine formation and the diffusion mechanism was studied in T. obesus meat inoculated with two histamine-forming bacteria, Morganella morganii NBRC 3168 (M. morganii NBRC 3168) and Photobacterium phosphoreum NBRC 13896 (P. phosphoreum NBRC 13896) and stored at 20 °C and 25 °C for 3 days. The histamine level of the inoculated A1 point accumulated at a level above 4000 mg/kg in the T. obesus sample inoculated with M. morganii NBRC 3168 for 48 h. And the most level of the histamine in the remote B point was 2000 mg/kg at the time the sample was inoculated with M. morganii NBRC 3168 and stored at 25 °C. For the P. phosphoreum NBRC 13896 however, the level of histamine at the inoculated point A was 1800 mg/kg for 48 h when it was stored at 25 °C, while the highest level of histamine distant from the inoculum site B point was found to be approximately 1800 mg/kg. In contrast, when stored at 20 °C, histamine level was higher for the sample inoculated with P. phosphoreum NBRC 13896 than with M. morganii NBRC 3168. While histamine was diffused from the inoculation point in the M. morganii NBRC 3168 sample, it was diffused not only from the inoculated point, but also the remote area in the P. phosphoreum NBRC 13896 sample.     

Effect of orange dietary fibre,oregano essential oil and packaging conditions on shelf-life of bologna sausages

The objective of this work was to study the effect of orange dietary fibre (1%) (ODF), oregano essential oil (0.02%) (OEO) and the storage conditions (vacuum, air and modified atmosphere) on the shelf-life of bologna sausage. Samples with ODF + OEO stored in vacuum packaging showed the lowest TBA values. ODF + OEO samples stored in vacuum packaging showed the lowest aerobic and lactic acid bacteria counts. The sensory evaluation scores were similar for samples with ODF + OEO and stored either in air or vacuum packaging. Orange dietary fibre and oregano essential oil could find a use in the food industry to improve the shelf-life of meat products.     

Isolation and identification of histamine-forming bacteria in tuna sandwiches

Forty-three tuna sandwiches sold in diners and convenience store in southern Taiwan were purchased and tested to determine the occurrence of histamine and histamine-forming bacteria. The levels of pH, water content, ash content, salt content, total volatile basic nitrogen (TVBN), aerobic plate count (APC), total coliform (TC), and Escherichia coli in all samples ranged from 4.5 to 6.9, 36.8% to 62.8%, 1.11% to 6.55%, 0.10% to 3.90%, 11.2 to 78.0 mg/100 g, <1.0 to 9.7 log CFU/g, <3 to 70,000 MPN/g and <3 to 1000 MPN/g, respectively. The average content of each of the eight biogenic amines in all samples was less than 3 mg/100 g, and only one tuna sandwich sample had histamine content (5.21 mg/100 g) greater than the 5.0 mg/100 g allowable limit suggested by the U.S. Food and Drug Administration. Five histamine-producing bacterial strains, capable of producing 42.1–595.4 ppm of histamine in trypticase soy broth supplemented with 1.0% L-histidine (TSBH), were identified as Hafnia alvei (one strain), Raoultella ornithinolytica (three strains) and Raoultella planticola (one strain), by 16S rDNA sequencing with PCR amplification.     

Effect of packaging and storage conditions on quality of shelled walnuts

The present study investigated the effect of packaging and storage conditions on quality of raw shelled walnuts. Walnut kernels were packaged in: (a) low density polyethylene (LDPE), 55 μm in thickness in air, (b) polyethylene terephthalate||polyethylene (PET||PE), 70 μm in thickness under N₂, and (c) PET-SiO_x||PE pouches, 62 μm in thickness under N₂. Samples were stored either under fluorescent light or in the dark at 4 or 20 °C for a period of 12 months. Quality parameters monitored were peroxide value (PV), hexanal, 2-thiobarbituric acid (TBA), odor, and taste of product. PV ranged between 0.3 for fresh walnut kernels and 31.4 meq O₂/kg oil for walnuts packaged in PE pouches exposed to light after 12 months of storage. Respective values for hexanal were <28.5 μg/kg and 36.0 mg/kg and for TBA ca. 0.2 and 11 mg MDA/kg. Values for odor ranged between 0.2 for fresh walnut kernels and 5.7 for walnut kernels packaged in PE exposed to light after 12 months of storage at 20 °C. Respective values for taste were 0.7 and 6.8. Taste proved to be a more sensitive attribute than odor. Based on shelf life (taste) values and PV data it is proposed that the upper limit value for PV is close to 10.0 meq O₂/kg walnut oil. Respective limit values for hexanal are 1–2 mg hexanal/kg walnut and for TBA is 1–2 mg malondialdehyde/kg walnut. Walnuts retained acceptable quality for ca. 2 months in PE-air, 4–5 months in PET||PE-N₂ and at least 12 months in PET-SiO_x||PE-N₂ pouches at 20 °C, with samples stored in the dark retaining slightly higher quality than those exposed to light. The effect of parameters investigated followed the sequence: temperature > degree of O₂ barrier > lighting conditions.     

Microbial and quality evaluation of green peppers stored in biodegradable film packaging

The effects of polylactic acid (PLA) based biodegradable film packaging on the microbial and physicochemical quality of green peppers (Capsicum annuum L.) were compared to the effects of low-density polyethylene (LDPE) film packaging, and perforated LDPE film packaging. Each package containing green peppers was heat-sealed and stored for 7 days at 10 °C. The microbial levels (aerobic bacteria, coliform bacteria, and yeast and moulds) and physicochemical properties such as colour, weight loss, hardness, ascorbic acid concentration, O₂ and CO₂ concentrations, were monitored during storage. Results indicated that the physicochemical properties of colour, hardness, ascorbic acid concentration, and microbial levels (total aerobic bacteria, and moulds and yeasts) did not show remarkable changes during storage period. The microbial levels in coliform bacteria were increased by less than 1 log CFU/g (0.2 log CFU/g) in the biodegradable film packaging, 2.3 log CFU/g in LDPE film package, and less than 1 log CFU/g (0.9 log CFU/g) in the perforated LDPE film package, after 7 days storage period. The results suggest that the biodegradable film with higher water vapor permeability can be used to maintain the quality and sanitary conditions (protection from microbial and insect contamination) of freshly harvested green peppers in modified atmosphere packaging.     

Monitoring the contents of biogenic amines in fish and fish products consumed in Korea

In order to obtain the level of biogenic amines in fish and fish products, a reversed phase high performance liquid chromatographic method was used for the quantitation of 12 biogenic amines in 300 fish and 80 fish products in Korea. Biogenic amines were extracted with hydrochloric acid, derivatized with dansyl chloride, separated using gradient elution, and detected by photodiode array and all detected biogenic amines were identified by UPLC/MS/MS. The detection levels of biogenic amines in the sample ranged from ND (not detected) to 30.6 mg/kg for agmatine, from ND to 390.0 mg/kg for cadaverine, from ND to 19.8 mg/kg for dopamine, from ND to 70.1 mg/kg for histamine, from ND to 17.8 mg/kg for noradrenaline, from ND to 29.7 mg/kg for 2-phenylethylamine, from ND to 43.0 mg/kg for putrescine, from ND to 11.9 mg/kg for serotonin, from ND to 9.5 mg/kg for spermidine, from ND to 13.5 mg/kg for spermine, from ND to 12.8 mg/kg for tryptamine, and from ND to 67.7 mg/kg for tyramine. Anchovy samples showed the high levels of histamine from 15.2 to 70.1 mg/kg, putrescine from 9.1 to 43.0 mg/kg, cadaverine from 152.2 to 90.0 mg/kg, and tyramine from 27.1 to 67.7 mg/kg. Agmatine was found at 30.6 mg/kg in cuttlefish. In the others fish samples agmatine detection levels were in the range from ND to 27.2 mg/kg. Spermidine and dopamine were detected about more than 85% samples in the range from ND to 19.3 mg/kg. Most of fish product samples showed less than 20 mg/kg of each biogenic amine. The maximum histamine and tyramine detection levels were respectively less than those of the regulation and recommendation.     

Validation of the procedure for the determination of aflatoxin B1 in animal liver using immunoaffinity columns and liquid chromatography with postcolumn derivatisation and fluorescence detection

The validation of the procedure for the determination of aflatoxin B₁ in animal liver (pig, chicken, turkey, beef, calf) was performed. The limit of detection (LOD) and limit of quantification (LOQ) were 2 ng/kg and 7.8 ng/kg, respectively. The repeatability of measurements, represented by the standard deviation (RSD_r) was 7.5%, 7.1%, and 4.8% at the contamination levels of 0.025 μg/kg, 0.050 μg/kg, and 0.075 μg/kg, respectively. The relative standard deviation for the within-laboratory reproducibility (RSD_R) was 18% at the level of 0.025 μg/kg and 22% at the levels of 0.050 μg/kg and 0.075 μg/kg. The measurement uncertainties at the same contamination levels were ±0.007 μg/kg, ±0.016 μg/kg, and ±0.023 μg/kg, respectively. The mean recovery was 72.8%, the decision limit (CCα) 0.063 μg/kg and the detection capability (CCβ) 0.080 μg/kg. The results indicate that the procedure is suitable for the determination of aflatoxin B₁ in animal liver and can be implemented for the routine analysis.     

Preventive effect of tannic acid in combination with modified atmospheric packaging on the quality losses of the refrigerated ground beef

Chemical, microbiological and sensorial changes of ground beef treated without and with tannic acid (200 mg/kg) and stored in air and under modified atmosphere packaging (MAP) (80%O₂/20%CO₂ or 10%O₂/20%CO₂/70%N₂) were monitored during 15 days of storage at 4 °C. During the storage, samples treated with tannic acid and kept under all packaging conditions contained lower peroxide value (PV) and thiobarbituric acid-reactive substances (TBARS) with coincidental lower non-haem iron content, compared with non-treated counterparts (P < 0.05). The sample packed in high oxygen MAP treated without and with tannic acid had the higher oxymyoglobin and a^* values and received the higher likeness scores for colour, whereas the samples stored in air and under low oxygen MAP showed the lower values, regardless of tannic acid treatment. After 15 days of storage, myosin heavy chain (MHC) and actin of all tannic acid treated samples underwent less degradation than those without tannic acid treatment for all packaging conditions. Degradation of MHC was more pronounced in samples kept under MAP with high oxygen. Psychrophilic bacterial count (PBC) of all tannic acid treated samples was lower, compared with that of non-treated samples (P < 0.05), irrespective of packaging condition. Therefore, tannic acid treated samples stored under high oxygen MAP could maintain the red colour and retard lipid oxidation and microbial growth of ground beef during refrigerated storage.     

Active film incorporated with sorbic acid on pastry dough conservation

Antimicrobial films, 25 and 70 μm-thick, incorporated with 0–6% of sorbic acid, were produced and layered with pastry dough without preservative to evaluate its antimicrobial action. Control pastry dough containing sorbate potassium was layered with low-density polyethylene films (LDPF). The sandwiches (films/pastry dough) were stored in LPDF bags at 8 ± 1 °C. The results of microbiological analyses obtained in the initial time for pastry dough with or without additive complied with the standards of the Brazilian current legislation. After 40 days of storage, the pastry dough layered with 70 μm-thick films, containing 3–6% of sorbic acid had significantly smaller microbial growth than, or equivalent to, the control pastry dough. Pastry dough with 25 μm-thick films, containing 6% sorbic acid, had the psychrotrophic count inferior to the control, and the aerobic mesophilic Staphylococcus spp. counts were 1 log cycle superior. The water activity and the moisture level showed no differences between the treatments throughout the storage time.     

Exposure assessment of mycotoxins in dairy milk

The objective of this study was to develop a quantitative Monte Carlo exposure assessment model for mycotoxins in dairy milk and to assess the potential human exposure levels. Mean concentrations of mycotoxins in milk were estimated using the simulation model (Aflatoxin M1 = 0.0161 μg/kg, Ochratoxin A = 0.0002 μg/kg, Deoxynivalenol = 1 μg/kg, Fumonisin B1 = 0.36 μg/kg, Zearalenone = 0.39 μg/kg, T-2 = 0.0722 μg/kg) while the simulated tolerable daily intakes (TDIs) from milk for males and females all fell below European Union guidelines. Aflatoxin M1 was the toxin of greatest concern as it had potential to exceed the EU limit of 0.05 μg/kg in milk. The sensitivity analysis identified the concentration of toxins in maize as the area which needs most attention in relation to crop management and agricultural practice. The sensitivity analysis assessed also identified the carry over rate as a factor closely related to risk and as a factor which required further research.     

Deoxynivalenol reduction during the frying process of turnover pie covers

The effect of the frying process on deoxynivalenol contamination was evaluated. Deoxynivalenol naturally contaminated flour (1200 μg/kg) and fortified flour artificially contaminated (260 μg/kg) were used to prepare turnover pie dough covers. Frying was performed at three temperatures (169 °C, 205 °C and 243 °C) for different times. The final time for cooking at every temperature was established by measuring the colour during the frying process. Deoxynivalenol reduction was greater in the artificially contaminated samples (>66% at 169 °C, 43% at 205 °C and 38% at 243 °C). For the level of 1200 μg/kg, the average percentage of deoxynivalenol reduction, based on medians, was 28% when the dough covers were fried at 169 °C, 21% at 205 °C and 20% at 243 °C.     

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).     

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.     

Inhibition of Staphylococcus aureus on beef by nisin-containing modified alginate films and beads

Nisin, a bacteriocin, was immobilized into palmitoylated alginate-based films or in activated alginate beads. Sterile beef muscle slices or ground beef were inoculated with Staphylococcus aureus at a level of 10⁴ CFU/g. Sliced beef was then coated with palmitoylated alginate-based films containing 0, 500 or 1000 IU/mL of nisin. Also, ground beef was mixed with 0, 500 or 1000 IU/mL of nisin covalently linked to activated alginate beads in order to evaluate the effect of nisin concentration on S. aureus level. The content of S. aureus in beef was determined during storage at 4 °C. Results demonstrated that after 7 days of storage, a reduction of 0.91 and 1.86 log CFU/cm² was observed on sliced beef covered with film containing 500 or 1000 IU/mL of nisin, respectively. After 14 days of storage, when nisin solution (500 or 1000 IU/g) was mixed with ground beef, 2.2 and 2.81 log CFU/g reductions of S. aureus counts were respectively observed. However, when nisin (500 or 1000 IU/g) was linked into activated alginate beads, 1.77 and 1.93 log CFU/g reductions of S. aureus counts were respectively observed (P ⩽ 0.05). These results suggest that sterile, hydrophobic and biodegradable films or beads incorporating various amounts of nisin could be used efficiently to control the growth of pathogens or microorganisms responsible of spoilage at the surface of round beef or other meat products.