气相色谱法检测消毒产品中的正丙醇与乙醇

使用HP-Plot Q色谱柱与FID检测器检测消毒剂中复配的正丙醇与乙醇含量,最大方法相对偏差(RSD)为2.14%,最小方法回收率为100.0%,乙醇与正丙醇的检出浓度为0.025%,是一种快速准确的一针检测法。     

Enhanced anti-biofilm activity of facile synthesized silver oxide nanoparticles against K. pneumoniae

Journal of Inorganic and Organometallic Polymers and Materials - The silver oxide nanoparticle was successfully synthesized using floral waste by simple one pot, cost effective method. The complete...     

微生物对化妆品杀菌防腐剂的耐受性和抗药性及其治理措施

简要介绍了微生物对化妆品杀菌防腐剂的耐受性与抗药性概念、抗药性微生物种属特性、杀菌剂的抗性水平以及抗性的风险评估和治理措施，旨在为提高化妆品（日化产品）和美容美发产品的质量，保障广大消费者的身体健康，并为科学合理使用现有杀菌防腐剂和研究开发新型杀菌防腐剂提供科学依据。     

Improvement of sediment microbial fuel cell performances by design and application of power management systems

One of the ways to generate clean and non-destructive energy is to use the energy stored in the biomass resources by the microbial fuel cells (MFCs). Sediment Microbial Fuel Cells (SMFCs) are a special type of MFCs that use organic materials in aquifers sediment to generate electricity. In this research, the effects of an increase in the electrode surface are investigated. The results showed that the increase in cathode electrode surface had better efficiency than the multi-cathode mode (maximum power generated for a 3-cathode electrode (27 cm³) and 1-cathode electrode (27 cm³) was 526 mW/cm² and 800 mW/cm², respectively. Another parameter affecting the performance of these systems is temperature. In the next step, the power generation rate was measured in different step currents and at different sample times. In the final stage, a power management system (PMS) was designed to optimally utilize the output energy of the improved SMFC, leading to an increase in the output voltage to 3.3 V.     

Biohydrogen by Rhodobacter sphaeroides during photo-fermentation: Mixed vs. sole carbon sources enhance bacterial growth and H2 production

Mixed carbon sources fermentation by bacteria is a promising approach for biohydrogen (H₂) production biotechnology. In the present study, growth and Н₂ production by purple bacteria Rhodobacter sphaeroides MDC6521 during mixed carbon sources (succinate + acetate, succinate + malate, and malate + acetate) photo-fermentation was investigated. The growth rate of bacteria in mixed carbon sources containing medium was of ∼0.33 h⁻¹ which was considerably higher (1.3–1.7-fold) compared with sole carbon substrate containing one. Moreover, the H₂ production during photo-fermentation of succinate and acetate mixture was of ∼6.5 mmol H₂ g⁻¹ (dry weight of biomass) and significantly more (∼2–3-fold) than that with appropriate sole sources and higher (1.5-fold) than that with succinate and malate mixture. Probably, supplementation of the mixed carbon sources into bacterial culture alters the mode of metabolism, resulting in enhanced H₂ production, thus they can be preferable compared to the sole carbon source. The changed F_OF₁-ATPase activity of membrane vesicles suggested its important role in the increase of Н₂ production efficiency. The results showed that mixed carbon sources provide more H₂ than the sole carbon substrates and succinate with acetate mixture is better than succinate with malate.     

Several melanosis-inhibiting formulas to enhance the quality of deepwater pink shrimp (Parapenaeus longirostris)

The aim of this work was to assess the effect of several melanosis-inhibiting formulations on quality of deepwater pink shrimp (Parapenaeus longirostris) during storage. The formulations tested were as follows: one containing 4-hexylresorcinol (0.1%) in combination with organic acids (citric, ascorbic and acetic) and chelating agents (ethylenediaminetetraacetic acid [EDTA] and di-sodium di-hydrogen pyrophosphate [PPi]); a commercial formula based on sulphites (3%), and another formulation containing a mixture of chitosan (0.3%) and commercial sulphites. Non-treated shrimp were used as control. The 4-hexylresorcinol-based formulation was more effective than 3% of commercial sulphite solutions in preventing melanosis. This treatment prolonged the sensory acceptability of shrimp by up to six days in ice storage. During chilled storage, the treatment with the 4-hexylresorcinol-based formula inhibited the growth of microorganisms by 1.5–2 log cycles as compared to commercial sulphites, especially H₂S-producers and pseudomonads. At the end of the experimental period, TVB-N levels were slightly higher in the lot treated with 4-hexylresorcinol (33 mg/100 mg) and reflected greater endogenous enzymatic activity, since the counts of the spoiler microorganisms remained around log 5 cfu/g or even lower. In general, the incorporation of chitosan to sulphites did not improve or produce a marked effect on shrimps during storage. During the sensory analysis, the panellists rated all the lots very similar, although the 4-hexylresorcinol formulation was the only one with a neutral odour at the end of the period. The 4-hexylresorcinol-based formulation induced yellow-green colorations to some extent in the cephalothorax, possibly due to the effect of organic acids and chelants, while the rest of the lots presented greyish/blackish colorations. Therefore, the formulation based on 4-hexylresorcinol may safely substitute traditional sulphites to improve the quality of fresh shrimp and prolong their shelf life during storage.     

Isolation and characterization of Listeria monocytogenes in Chinese food obtained from the central area of China

The objective of this study was to investigate the prevalence and characteristics of Listeria monocytogenes isolated from Chinese food, including frozen dumplings, flavored raw meat, roasted meat, braised meat, and a cold vegetable dish with sauce. A total of 900 food samples were collected from supermarkets, open-air markets, and delicatessens in three large cities in the central area of China to examine the presence of L. monocytogenes; 21 (2.3%) of the samples were positive for this pathogen. Among the different samples, braised meat showed the highest L. monocytogenes detection rate (4.4%). Samples obtained from delicatessens showed a much higher L. monocytogenes contamination rate (8.3%) than those from open-air markets (6.7%) or supermarkets (0%). Multilocus sequence typing (MLST) analysis indicated that the 21 bacterial isolates belonged to 12 ST subgroups. ST5 was the largest and contained 7 isolates (33.3%); it was followed by ST474, ST121 and ST9 (each containing 2 isolates [10.5%]). Antibiotic susceptibility analysis showed that the 21 L. monocytogenes isolates were thoroughly resistant to cefoxitin but highly susceptible to doxycycline and ciprofloxacin. The presence of 10 virulence genes was evaluated by PCR, which showed that inlA, inlC, inlJ, prfA, hlyA, and plcB were present in all isolates and that inlB, actA, plcA and iap were present in 71.4–90.5% of the isolates. This study provides a useful reference for risk assessment and control of L. monocytogenes contamination in Chinese food and for the treatment of clinical listeriosis.