吸取"非典"教训改进玄关设计

“玄关”是由户外入户的过渡专用空间。针对今年我国部分地区“非典”流行期间的卫生措施，指出了“玄关”对室内环境卫生安全的重要性，并对“玄关”面积、设施、装修等提出了一些设想。     

A new UVC-LED system for disinfection of pathogens generated by toilet flushing

A new disinfection system utilizing UVC-LED irradiation was developed. The system was affixed to the toilet seat, and it was challenged by three bacteria strains. Different configurations were tested: 3-LEDs, 5-LEDs (two variants), and 8-LEDs. To determine the arrangement designs of LEDs with the optimum efficacy, two variants of 5-LEDs configurations were additionally considered—uniform and concentrated (2-sided) distributions. It was noticed that disinfection efficacy initially increased with the number of LEDs, but with 8-LEDs, the trend became almost non-obvious for surface disinfection and just marginally increased for airborne disinfection. The mean efficiencies for the surface disinfection ranged from 55.17 ± 23.89% to 72.80 ± 4.13% for E. coli; 36.65 ± 2.99% to 50.05 ± 13.38% for S. typhimurium; and 8.81 ± 3.23% to 39.43 ± 9.33% for S. epidermidis. Likewise, the mean efficiencies for airborne disinfection ranged from 42.17 ± 8.18% to 70.70 ± 4.80%; 40.40 ± 17.90% to 58.31 ± 13.87%; and 24.16 ± 3.81% to 42.79 ± 10.20% for E. coli; S. typhimurium; and S. epidermidis, respectively. Furthermore, the efficacy of the uniform irradiation was nearly twice that of the concentrated irradiation for surface disinfection and 17.70% higher for airborne disinfection, when tested against E coli. Collectively, these very promising results showcased that this compact, sustainable, and localized disinfection system has a high potential for the next generation of disinfection devices.     

甜菜糖品卫生细菌学检测实验体系的建立与应用 食糖菌落总数的测定与分析

本文建立了甜菜糖品卫生细菌学检测实验体系中菌落总数测定技术，用以评估甜菜糖细菌污染程度，为精品卫生微生物学检验奠定了技术基础。菌落测定为食糖卫生评价提供了依据，为制糖工艺流程微生物污染和食糖贮存环境评估提供技术选择。5个糖期食糖检测表明，技术稳定可靠。不同糖厂、同一糖厂不同批次产品存在着不同的细菌污染情况，菌落测定技术为制糖工艺确定杀菌剂的类型和数量提供了直接依据。     

生物传感器在食品工业中的应用

就生物传感器在食品工业中的应用及其前景进行了综述，主要包括食品鲜度、成熟度、滋味测定；食品细菌及原病菌测定；食品毒素及残留农药测定；食品添加剂的测定。     

Efficacy of heat treatment in the reduction of salmonellae and Escherichia coli O157:H– on alfalfa, mung bean and radish seeds used for sprout production

We studied the effect of hot-water treatment at various time/temperature regimes to design a decontamination process which is consistent with the recommendation of the National Advisory Committee on Microbiological Criteria for Foods (NACMCF) to reduce pathogens on seeds by 5log cfu/g. Alfalfa, mung bean and radish seeds were inoculated by immersion with more than 10⁷ cfu/g of enterobacteria (Salmonella Senftenberg W775, S. Bovismorbificans and Escherichia coli O157:H^–), dried and stored at 2 °C. The numbers of salmonellae and E. coli O157:H^– on these seeds remained unchanged during storage for 8 weeks. To achieve sprouting rates of more than 95%, time-temperature regimes were defined. The thermal treatment of contaminated mung bean (2–20 min for 55–80 °C), radish and alfalfa seeds 0.5–8 min (53–64 °C) reduced all pathogens by more than 5log cfu/g. For S. Senftenberg W775 on radish seeds, D values of 3.2, 1.9 and 0.6 min were determined for exposure at 53, 55 and 58 °C and a z value of 6.2 °C was calculated. For alfalfa seeds, the respective D values were 3.0, 1.6, and 0.4 min and the z value was the same as that determined for radish seeds.     

Pathogen-specific incidence rate of clinical mastitis in Flemish dairy herds,severity, and association with herd hygiene

A one-year survey on clinical mastitis was conducted on 50 randomly selected commercial Flemish dairy herds to estimate the pathogen-specific incidence rate of clinical mastitis (IRCM). The severity of the cases and the potential associations with herd hygiene were studied. Participating producers sampled 845 cases and 692 dairy cows. The mean and median IRCM was estimated at 7.4 and 5.3 quarter cases per 10,000 cow-days at risk, respectively. A large between-herd variation was observed (range of 0–21.3). In general, the IRCM was lower in heifers compared with multiparous cows (2.9 vs. 11.0 quarter cases per 10,000 cow-days at risk). However, the overall IRCM in the first week after calving was higher in heifers compared with cows (43.4 vs. 31.6 quarter cases per 10,000 cow-days at risk). Streptococcus uberis (18.2% of the cases) and Escherichia coli (15.5%) were the most frequently isolated pathogens and no growth was observed in 19.9% of the cases. The majority of the cases (63.1%) were mild (only clots in milk). Moderate (hard quarter without general signs) and severe symptoms (systemic illness) were observed in 29.9 and 7.0% of the cases, respectively. Isolation of E. coli (vs. any other culture result) was more likely in moderate and severe cases compared with mild cases. Overall IRCM and E. coli IRCM were higher in dirty compared with clean herds based on udder hygiene scores (9.0 and 1.7 vs. 6.0 and 0.6 quarter cases per 10,000 cow-days at risk, respectively). This study broadens the knowledge on clinical mastitis in Flemish dairy herds and underlines the high risk of CM in early-lactation heifers, the role of the so-called environmental pathogens, and herd hygiene.     

Microwave-assisted low-cost synthesis of sucrose-soya ester from vegetable oil refinery by-product and its application in toothpaste formulation for oral hygiene

The major drawbacks of the sucrose ester (SE), in spite of being a green nonionic surfactant, are the difficulty of synthesis and higher cost. Distilled soya acid oil (DSAO) obtained as by-product from a vegetable oil refinery was used for the synthesis of fatty acid methyl ester (SAFAME). Microwave-assisted method (680 watts system), which is greener and more efficient was used for the synthesis of SAFAME at 99.3% conversion using 2 wt% sulfuric acid catalyst within 30 min as well as for the synthesis of SE at 82.5% conversion using 5 wt% K₂CO₃ catalyst within 45 min. Both synthesis steps were monitored and characterized by using thin-layer chromatography, gas chromatography, ¹H NMR, and FT-IR. The surface tension of 1% aq. solution of SE was 29.58 mN m⁻¹, while the interfacial tension of n-heptane-1% aq. solution was observed to be 3.29 mN m⁻¹. The critical micelle concentration was 74.24 mg L⁻¹. Foaming properties, emulsion stability, and wetting power were determined by using standard techniques. The SE was used for the development of desensitizing anticavity toothpaste formulation and the various properties were evaluated in comparison with the commercial toothpaste formulation available in the market. The results show that the partially renewable surfactants like sodium dodecyl sulfate (SDS) and sodium lauryl ether sulfate (SLES) can be replaced partially or fully with the biobased renewable SE surfactants in the various personal care formulations including toothpaste.     

快速检测技术在食品安全监督管理工作中的应用

本文主要介绍了将快速、灵敏、方便、准确的食品安全快速检测技术应用在食品安全监督管理工作中的意义和作用,以及时控制、减轻、消除食品突发事故及有毒有害物质对人体潜在的危害、降低食物中毒发生率,提高工作效率,探索新的食品卫生监管模式,为促进我市食品安全监督保障工作的进一步顺利开展起到重要的技术支撑作用。     

薄层色谱-表面增强拉曼光谱法快速检测改善睡眠类保健食品的主要成分及其光谱表征

目的建立薄层色谱(TLC)与表面增强拉曼光谱(SERS)联用技术对改善睡眠类保健食品的主要成分(褪黑素、维生素B_6)的快速检测新方法。方法以环己烷-乙酸乙酯-乙醇(5∶3.5∶2,V/V)为展开剂,利用TLC将改善睡眠类保健食品中主要成分与保健食品基质初步分离,在UV_(254nm)下检测定位;以780 nm激光为激发波长,水相银胶溶液为表面增强剂,采用SERS法对TLC上的微量成分进行原位定性检测。通过模拟阳性样品试验,考察保健食品基质对褪黑素、维生素B_6的TLC-SERS的影响,并考察褪黑素及维生素B_6的检出限,并随机对市售4种改善睡眠类保健食品进行检测。结果褪黑素、维生素B_6的TLC-SERS与相应对照品的拉曼光谱特征峰存在明显相关性;保健食品的基质对褪黑素和维生素B_6的检测不存在干扰;褪黑素和维生素B_6的检出限为10、5μg。市售改善睡眠类保健食品主要成分的TLC-SERS与褪黑素或维生素B_6基本相同。结论本法准确、灵敏、快速、简单,为检测混合样品等复杂体系主要成分的定性鉴别检测提供一种有效方法。     

一步法快速检测食品中大肠菌群

目的 建立一步法快速检测食品中大肠菌群的方法。方法 食品参照GB 4789.3-2016进行前处理后, 放入到大肠菌群检测试剂盒的样品制备瓶内, 振摇制成样品匀液。将样品匀液1 mL加入到检测瓶中, 配套使用在食源性致病菌同步检测仪中培养检测。结果 在市场上购买3份样品用该方法检测, 并同GB 4789.3-2016检测结果对比, 2种方法吻合率高, 且本方法大肠菌群检测限能够达到10 CFU/g或mL, 70~480 min内可获得检测结果。结论 该方法可以实现对大肠菌群的快速检测, 且操作简便, 结果准确, 为食品卫生质量监管提供参考。