Use of a commercial mixture of volatile compounds from the fungus Muscodor to inhibit Salmonella in ground turkey and beef

Additional interventions to reduce the risk of Salmonella in ground meat products are needed in the industry. Fungi in the genus Muscodor produce an array of volatile compounds with antimicrobial activity. A commercial mixture of these volatile compounds (all considered to be GRAS), in proportions similar to that produced by the fungus, was assessed for its inhibitory activity against Salmonella in vitro. The minimal inhibitory concentration of the volatiles mixture for growth of Salmonella enterica in Mueller-Hinton broth was 0.5% (v/v). Exposure to the vapor phase of the volatile compounds similarly inhibited visible growth of Salmonella on agar (up to 6 cm zone of inhibition). Addition of the volatiles mixture (0.25%–1.0% v/w) inhibited Salmonella by 1.5 and 2.8 log₁₀ CFU in ground turkey (85% or 93% lean, respectively) and 2.2 and 1.7 log₁₀ CFU in ground beef (73% or 93% lean, respectively) during a 5 day period at 8 °C. Addition of the volatiles also inhibited growth of normal microflora on ground turkey at 8 °C by approximately 5.3 log₁₀ CFU. These findings indicate this mixture of volatile compounds retards growth of spoilage organisms and Salmonella in ground meat.     

Occurrence of volatile organic compounds in foods from the Belgian market and dietary exposure assessment

Because volatile organic compounds (VOCs) are ubiquitous in the environment and may represent health risks, it is important to know whether they are present in our diet and to identify possible sources in order to reduce daily intake. In the present study, 377 food samples from the Belgian market were screened for the presence of 21 VOCs. The most prevalent of these compounds and respective percentages of occurrence were: chloroform (97%), toluene (95%), ethyl benzene (80%), o-xylene (79%) and benzene (58%). Dietary intake by the Belgian adult population was calculated for these five most prevalent VOCs. The maximum probabilistic dietary intake was with 0.151, 0.645, 0.138, 0.066 and 0.118 μg kg bw⁻¹ day⁻¹ for chloroform, toluene, ethyl benzene, o-xylene and benzene respectively below the minimal risk level (MRL) set for each of the VOCs for oral chronic/acute exposure and below the Reference Dose for Chronic Oral Exposure (RfD). The Margin of Exposure (MOE) for benzene was significantly larger than 100,000. Therefore, it was concluded that the dietary exposure to VOCs for the Belgian adult population does not impose health risks.     

鄂尔多斯盆地西峰油田原油含氮化合物分布特征与油气运移

为了给鄂尔多斯盆地西峰油田进一步勘探决策提供油气运移方面的依据，根据对该油田延长组原油的中性含氮化合物研究探讨油气运移问题。结果表明，原油的中性含氮化合物在平面和剖面方向均存在着明显的运移分馏效应．但是长。油层组原油中咔唑类化合物的绝对丰度和异构体参数值变化较小，说明该油层组油气经历了短距离运移。根据含氮化合物的运移分馏特征认为，平面上长s油层组油气主要从北东方向注入并向南西运移，部分原油从南部西33井地区注入并向北部运移；纵向上长s油层组油气由上向下运移，研究区西部长8、长3和延8油层组油气则自下而上从长。油层组向延s油层组方向运移。这种油气运移方向与研究区流体压力的指向一致。依据油气运移途径推断，该区油气主要来自长7段油源层。图5表2参10     

Composition and distribution of NSO compounds in two different shales at the early maturity stage characterized by negative ion electrospray ionization coupled with Fourier transform ion cyclotron resonance mass spectrometry

Gas chromatography/mass spectrometry (GC/MS) can only analyze volatile molecular compounds, and it has limitations when applied to determine the complex components of crude oils and hydrocarbon source rocks. Based on Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) and GC/MS analyses, the molecular compositions of NSO compounds in extracts from the Permian Dalong Formation, Sichuan Basin and the Permian Lucaogou Formation, Junggar Basin in China were compared. Analyses of types of heteroatoms present (S₁, S₂, S₃, OS, OS₂, O₂S, NS, and NOS compounds) suggest that marine shales from the Dalong Formation are mainly composed of carboxylic acids (O₂ compounds) with a high abundance of fatty acids, indicating a marine phytoplankton organic source. However, lacustrine shales from the Lucaogou Formation are dominated by pyrrolic compounds (N₁ compounds) with abundant dibenzocarbazole. It suggests that the organic source materials may be derived from lower aquatic organisms and lacustrine algae. Overall, FT-ICR-MS has potential for applications in analyses and determination of depositional environments and organic sources in petroleum geology.