In vitro control of growth and ochratoxin A production by butylated hydroxyanisole in Aspergillus section Nigri species

This study was carried out to determine the efficacy of phenolic antioxidant butylated hydroxyanisole (BHA) under different interacting water activity (a_W) and temperature regimes on the lag phase and growth rate by Aspergillus section Nigri strains. In this experiment four A. section Nigri strains were used. Peanut meal extract agar (PMEA) was prepared at 2%. The a_W of the medium was adjusted to 0.995, 0.980 and 0.930, BHA at 1, 5, 10 and 20 mmol l^?1 was added to the basic medium. The plates were inoculated and incubated for 30 days at 18 and 25 °C. Radial growth rates (mm d^?1) and lag phase (h) were calculated. In control treatments, the growth rate decreased as water activity reduced in all strains assayed. At all a_W levels tested, BHA at 20 mmol l^?1 completely inhibited growth. In general, at 10 mmol l^?1 and 0.995 and 0.980a_W level, a significant reduction respect to control was observed. This antioxidant completely inhibited OTA production, at concentrations of 20 mmol l^?1, regardless of a_W used by all the strains evaluated.     

Antifungal activity mode of Aspergillus ochraceus by bacillomycin D and its inhibition of ochratoxin A (OTA) production in food samples

The inhibition effects of bacillomycin D on the growth of Aspergillus ochraceus and the production of ochratoxin A (OTA) in food samples were investigated. The mycelia growth and sporulation were completely inhibited by 30 μg/mL of bacillomycin D. Microscopic morphological changes such as the distortion of hyphae and the disruption of spores at 20 μg/mL of bacillomycin D were significantly observed. The use of bacillomycin D resulted in cell damage, nucleic acids and proteins divulge, and more production of reactive oxygen species (ROS), and all these factors actively contributed to the promotion of apoptosis of A. ochraceus. In addition, 90 μg/g of bacillomycin D completely inhibited the growth of A. ochraceus and the production of OTA in food samples. Our results suggested that bacillomycin D showed a significant antifungal activity against A. ochraceus that could be used as a potential natural antimicrobial to control food contamination and ensure food safety.     

Effect of sulfur dioxide and ethanol concentration on fungal profile and ochratoxin a production by Aspergillus carbonarius during wine making

Fungal profiles and ochratoxin A (OTA) accumulation during wine making were investigated using five different wine grape cultivars, Cabernet Sauvignon, Pinot Noir, Merlot, Syrah and Petit Verdot and the intrinsic influences caused by sulfur dioxide, ethanol and combine effect of ethanol and reducing sugar were analyzed using Cabernet Sauvignon and inoculation of Aspergillus carbonarius. Aspergillus spp. and Penicillium spp. were found as the major fungi in all winemaking processes and were highly correlated with OTA accumulation in wine. Most fungi died and OTA production decreased after 48 h of alcoholic fermentation, being consistent with the period when ethanol accumulation increased. The addition of SO₂ significantly inhibited the growth and OTA production of A. carbonarius with complete inhibition at 500 mg/L. When the ethanol concentration in the must increased to the range of 2–4%, growth and OTA production of A. carbonarius were significantly inhibited. Reducing sugar concentration had no significant effect on the growth and OTA production of A. carbonarius within the levels changing during the winemaking. Therefore, the increase of ethanol concentration played an important role in causing the decrease of fungal contamination and OTA accumulation during winemaking.     

Aflatoxin B1 production by Aspergillus parasiticus and strains of Aspergillus section Nigri in currants of Greek origin

Aflatoxin B₁ (AFB₁) mostly produced by Aspergillus flavus and Aspergillus parasiticus, is an extremely toxic and carcinogenic metabolite. Currants are used in the Mediterranean diet as a food with antioxidant properties. Four strains of Aspergillus section Nigri have been isolated from currants originated from Crete and Corinth. In this study AFB₁ production by A. parasiticus and the four strains of Aspergillus section Nigri in Cretan and Corinthian currants (Vitis vinifera L.) is investigated. AFB₁ determination was performed by HPLC–FID. Results revealed that the four strains Aspergillus section Nigri, as well as the aflatoxigenic strain A. parasiticus produced AFB₁ (0.0052–1.31 μg AFB₁ 15 g⁻¹, corresponding to 0.0003–0.087 μg AFB₁ g⁻¹) in both type of currants (Cretan and Corinthian) on the 12th day of observation. Moreover, AFB₁ production, by A. parasiticus in the synthetic Yeast Extract Sucrose (YES) medium was also studied. The ability of AFB₁ production has been affected by the special characteristics of each isolate and the currants substrate.     

Detection of potentially mycotoxigenic Aspergillus species in Capsicum powder by a highly sensitive PCR-based detection method

The objective of this study was to gain information about the toxigenic Aspergillus species present in a wide survey of retail samples of paprika and chilli collected in Spain. Detection of these mycotoxigenic species was performed with an optimized protocol for paprika and chilli which includes a set of species-specific PCR assays. Occurrence of toxigenic Aspergillus species was higher in paprika than in chilli samples (83.9% and 64.5%, respectively). Paprika showed also the highest percentage of co-occurrence of two or more different species (43.6%) in comparison with chilli (35.5%). The most common aspergilli were Aspergillus niger aggregate (67.7%), followed by Aspergillus flavus (49.5%). Aspergillus carbonarius, Aspergillus parasiticus and Aspergillus steynii were detected at lower frequency (1.1%). The high co-occurrence of Aspergillus species able to produce ochratoxin A and aflatoxins, particularly in paprika, suggested the need of a more efficient control during processing and storage to reduce fungal contamination, and additional legislation to consider the simultaneous presence of both toxins in these matrices.     

Study of Saccharomyces cerevisiae W13 as a functional starter for the removal of ochratoxin A

In this paper, a wild strain of Saccharomyces cerevisiae (W13) was studied for its OTA-removal ability, growth pattern and alcoholic fermentation profile at two different temperatures (25 and 30 °C) and two different sugar levels (200 and 250 g l⁻¹), with or without supplementation of medium with diammonium phosphate (DAP). A commercial strain (Lallemand EC1118) and a collection isolate (DBVPG 6500) of S. cerevisiae were also studied. All the strains were able to conclude fermentation, with S. cerevisiae W13 producing higher ethanol and glycerol contents; moreover, the wild strain was able to remove OTA (reduction of 6–57.21%), with the highest removing effect observed at 30 °C with 250 g l⁻¹ sugar and after 3 days.In addition, S. cerevisiae W13 was studied for its technological and qualitative traits, as it showed a high tolerance to single and combined stress conditions, β-d-glucosidase, pectolytic and xylanase activities, a low level of hydrogen sulphide production, a low-to-medium parietal interaction with phenolic compounds and no biogenic amines formation.The findings of this work have an applicative value for the potentiality of using S. cerevisiae W13 as functional starter for the production of wines with improved qualitative and food safety characteristics.     

应用地震资料建立压性盆地平衡剖面

由地震资料分析认为,造成压性盆地地层缩短的原因主要有两方面:①断裂作用;②褶皱作用。由断层作用造成的地层缩短量等于水平断距;由褶皱造成的地层缩短量等于褶皱弯曲部分的长度减去弯曲剖分的水平距离。应用地层缩短量可建立压性盆地平衡后的古地质构造发育史剖面图、平面图,并可间接地研究盆地不同位置、不同地质时期的构造运动强度。     

Reassessment of the acrylamide risk: Belgium as a case-study

Acrylamide is a food process contaminant with carcinogenic and genotoxic properties. As a result of intensive research, numerous mitigation initiatives to prevent its formation were suggested and various of them were implemented in the food chain. To evaluate if the mitigation strategies applied were significant, a comparison was made between two time periods (2002–2007 versus 2008–2013) in terms of acrylamide food levels and dietary exposure in Belgian.The most important changes observed are a significant decrease of the acrylamide content in potato crisps and gingerbread, and a significant increase in (instant) coffee. Additionally, the acrylamide content of breakfast cereals, bread and rolls, chocolate and baby biscuits showed a downward trend, whereas for coffee substitute and ready-to-eat French fries (mainly obtained from catering facilities), an upward, although not significant, trend was observed. These changes resulted in only a slight, but insignificant decline of the overall dietary exposure of adults, adolescents and children.The mean and P95 intake estimated in the 2008–2013 period for these consumer groups corresponded to margins of exposure (MOE) ranging between 515 and 236 and between 155 and 71, respectively, when based on the endpoint for neoplastic effects (BMDL₁₀ = 0.17 mg/kg bw per day). Such low MOE values indicate that acrylamide remains an issue for public concern, requiring renewed attention.     

Biogas production as affected by heavy metals in the anaerobic digestion of sludge

Biogas production can be generated by sludge digestion process in the form of methane which in some plants is collected and used as a source of energy. Sewage which is collected from mixed industrial and domestic population may be contaminated with metals and industrial chemicals. The aim of the present study is to investigate the effect of heavy metals on the biogas production in the anaerobic digestion process for the treatment of sewage sludge. The selected metals are Hg, Cd and Cr III. The toxic effect and the inhibitory impact of the digestion process are among the objective of the study. The fate and toxic effects of heavy metals on the biogas production was determined.The sewage sludge samples were separated from the sewage water of the pilot plant at the National Research Centre, TDC site. The effect of heavy metals on the biogas production of the anaerobic digester was studied. The inhibitory effect on the biogas production and toxic level of metals was determined in this study. The general ranking of heavy metal toxicity appears to be Hg > Cd > Cr (III). The present investigation reveals that heavy metals in addition to the anaerobic digester decreased the biogas production as an indication of efficiency of the process. A significant decrease in gas production and volatile organic matter removal was obtained. It was also noted that an accumulation of organic acid intermediates was obtained as a result of methanogenic bacterial inhibition. This accumulation was limited during the pulse feed of metals. This is due to the rapid poisoning of the active bacterial forms in the digester.     

涡轮钻具支承节中载荷分流碟簧公差的合理确定

针对带独立支承节涡轮钻具中载荷分流碟形弹簧载荷偏差的严格要求,推导出在各尺寸偏差同时出现时载荷偏差的微分公式。用该公式校验初始方案,并确定了合理的碟形弹簧的公差值。     

Gaseous allyl isothiocyanate to inhibit the production of aflatoxins,beauvericin and enniatins by Aspergillus parasiticus and Fusarium poae in wheat flour

There is a growing concern about the presence of mycotoxins in foods, since up to 25% of cereals and cereal foods are contaminated with these compounds. Moreover, the general public is against the use of synthetic preservatives in foods and the use of natural antimicrobials in foods is a current trend. Allyl isothiocyanate (AITC) is a volatile antimicrobial derived from oriental and black mustard. The objective of this work was to evaluate the capacity of gaseous AITC in inhibiting the production of mycotoxins by Aspergillus parasiticus (aflatoxin producer) and Fusarium poae (beauvercin and enniatin producer) in wheat flour. Petri dish lids filled with 2 g of wheat flour were inoculated with 10⁴ conidia/g of A. parasiticus or F. poae and placed in a 1 L mason jar. AITC was added at 0.1, 1 or 10 µL/L in the gaseous phase. Jars were hermetically closed and kept at 23 °C for 30 d. Mycotoxins were identified and quantified by LC-MS/MS. Even 0.1 µL/L of AITC was able to produce 6.9–23% reduction of mycotoxin production. In general, synthesis of aflatoxins and beauvericin was more affected than enniatins. The use of AITC at 10 µL/L completely inhibited the production of all mycotoxins for 30 d. AITC at low doses could be added to flour packages in order to inhibit the production of potentially dangerous mycotoxins.     

Diene fraction from pyrolysis as a feedstock for the production of light-colored petroleum-polymer resins

Translated from Khimiya i Tekhnologiya Topliv i Masel, No. 2, pp. 5–6, February, 1993.     

陆相沉积油层水平井水平段轨迹对产能及采收率影响的研究

我国油田多属陆相沉积,油层内或多或少地存在着薄厚不等的夹层或隔层,而且分布不均。对于无气顶底水的这类油层,研究了有隔层水平井产能下降的幅度,研究了与油层相交贯穿油层上下的大斜度水平井和平行油层水平井的产能和采收率。计算分析结果表明：①存在夹层、隔层的油层不适合打平行油层的水平井;②对含有夹层、隔层的油层,选择与油层相交贯穿油层上下的大斜度水平井,可有效地降低夹层、隔层对产能和采收率的负面影响;③当相交油层的水平井长度为平行油层水平井长度的１．１５倍时,无论油层有无夹层、隔层,其产能要大于或等于相应平行油层水平井的产能,而且采收率不会受夹层、隔层的影响;④对无气顶底水的陆相沉积油层,选择与油层相交的长度略长的水平井是稳妥的。图３参６（陈志宏摘）     

Effect of UV-C treatment on the microbial population of white and red wines,as revealed by conventional plating and PMA-qPCR methods

Ultraviolet C (UV-C) irradiation is one of the emerging techniques for the inactivation of microorganisms in liquid food products, and it holds considerable promise also for treatment of wine. This application can be of particular interest to reduce or even eliminate the use of sulphur dioxide as a preservative in winemaking, given its potential health risks.In this study, UV-C light treatment was applied to ten different white and red wines during winemaking, for the first time at industrial scale, using a commercial turbulent flow system. The effect of 1.0 kJ/l dosage treatment on the viability of the natural microbial population, i.e., total yeasts, lactic acid bacteria and acetic acid bacteria, was investigated both with conventional plating and optimized specific propidium monoazide (PMA)-qPCR. Results of the two methods were mainly concordant for control and UV-C treated samples, and, in some cases, PMA-qPCR was able to detect small amounts of viable cells, probably in the VBNC state. Remarkably, PMA-qPCR allowed to obtain reliable results much faster than conventional plating methods.Data indicated that the UV-C irradiation was effective in reducing microbial counts for up to five log CFU/ml, depending on the wine (white or red) and on the microbial load of the sample. The treatment was much more effective in white wines: a statistically significant decrease was observed for putative spoilage-related bacteria, besides the most pronounced effect on yeast cells.Outcomes strongly support the applicability of UV-C treatment for white wine production, thanks to its efficacy towards all the microbial groups considered.     

利用反射波的相关特性拟合零炮检距剖面——剔除追踪拟合方法

基于射线原理的ＣＤＰ道集,经过动校正以后,相邻道的地震反射波具有波形相似,时间近似相等的特性,如果不具有这种特性,则认为是干扰波或受到了干扰的反射波。根据这一原理,我们可以选择一个有限小的时窗进行剔除追踪拟合,剔除干扰波,得到剔除追踪拟合剖面。从试验结果来看,剔除追踪拟合剖成比水平叠加剖面,多项式拟合剖面,剔除拟合剖面的分辨率、信噪比,同相轴的连续性等都有明显的改善。