班产3万份保鲜方便米粉车间设计初探

在对保鲜方便米粉生产实践及工艺分析的基础上，对国内外食品机械设备进行对比选型，设计了一套适于生产出口欧盟等国，班产3万份保鲜方便米粉的生产线，并对保鲜方便米粉车间设计中出现的技术问题提出了有效的解决方案。     

基于长短期记忆神经网络的重大活动中鲜(冻)肉制品铅含量风险预测

目的 针对未来时间内重大活动举办地鲜(冻)肉制品铅含量风险预测的问题,建立基于LSTM的时间序列预测模型,对当地鲜(冻)肉制品铅含量进行风险评估与预测预警。方法 通过收集2011-2020年国家市场监督管理总局日常食品监督管理抽检数据,筛选出北京的鲜(冻)肉制品的抽检数据,构建数据集并进行预处理,按照7:2:1的比例划分训练集、验证集和测试集,基于Tensorflow平台构建4层LSTM模型并进行训练,基于重大活动举办前10天的鲜(冻)制品铅含量数据,对未来1天的鲜(冻)制品铅含量风险进行预测。结果 实验表明,经过50轮模型迭代训练,训练集和测试集Loss指标收敛至0.084,经过5次训练后的模型评估参数RMSE为0.192,R2_score为0.916,模型误差较小、准确度较高。结论 基于LSTM的鲜(冻)肉制品铅含量风险预测模型整体性能较好,可应用于重大活动举办地的食品风险预测,并精准指导监督抽检。     

不同细菌胞外产物对腐败希瓦氏菌低温下生长代谢的影响

为研究荧光假单胞菌(Pseudomonas fluorescens,P.fluorescens)、嗜水气单胞菌(Aeromonas hydrophila,A.hydrophila)、温和气单胞菌(Aeromonas sobria,A.sobria)的胞外产物对腐败希瓦氏菌(Shewanella putrefaciens,S.putrefaciens)低温下生长的影响,提取这3株菌株的胞外产物与无菌脑心浸肉汤(Brain Heart Infusion,BHI)培养基混合,再将S.putrefaciens分别接种至混合培养液中,于(4±1)℃下培养12d,测定培养液中S.putrefaciens的菌落总数及胞外蛋白酶、生物膜、挥发性盐基氮(TVB-N)、总氨基酸和腐胺的变化。结果表明:P.fluorescens、A.hydrophila和A.sobria的胞外产物对S.putrefaciens的延滞期和对数期几乎没有影响,但是A.sobria的胞外产物可以抑制S.putrefaciens稳定期的生长,而且随着贮藏时间的延长,相比于P.fluorescens、A.hydrophila,A.sobria的胞外产物对S.putrefaciens的生物膜、胞外蛋白酶形成以及致腐败能力的抑制作用更强。     

油莎豆非油制品加工研究进展

油莎豆又称虎坚果,莎草科莎草属植物,原产于非洲,作为一种集粮、油、牧、饲于一体的新兴农作物已被我国引进种植。油莎豆具有较高的经济价值和开发潜力,其块茎不仅营养丰富,还具有降血压、降血脂、降低胆固醇等医学保健功能。从油莎豆主粮制品、饮品、发酵制品和其他制品几个领域,阐述了油莎豆非油制品加工的最新研究进展,并对其未来发展前景进行展望,以期为油莎豆块茎以及其提油后副产物的开发利用提供参考。     

Variation of aflatoxin M1 contamination in milk and milk products collected during winter and summer seasons

Total 221 samples of milk and milk products were collected during winter (November 2011–February 2012) and 212 samples were collected during summer (May–August 2012) from central areas of Punjab, Pakistan. The samples were analyzed for the presence of aflatoxin M₁ (AFM₁) with a validated HPLC method equipped with florescence detector. The results revealed that from winter season almost 45% samples of milk and milk products were found to be contaminated with AFM₁ i.e. 40% of raw milk, 51% of UHT milk, 37% of yogurt, 60% of butter and 43% of ice cream samples and 27, 24, 25, 34 and 17% of samples were found above the recommended limit for AFM₁, respectively. However, from summer season 32% samples of milk and milk products were found to be contaminated i.e. 36% of raw milk, 31% of UHT milk, 29% of yogurt, 40% of butter and 24% of ice cream and 23, 23, 18, 20 and 5% of samples were found above the permissible limit for AFM₁, respectively. The levels of contamination in winter milk and milk product samples were significantly higher (α ≤ 0.05) than in summer season. The occurrence of AFM₁ in milk and milk products were higher, demanding to implement strict regulations and also urged the need for continuous monitoring of milk and milk products in order to minimize the health hazards.     

NaCl-free processing,acidification, smoking and high pressure: Effects on growth of Listeria monocytogenes and Salmonella enterica in QDS processed® dry-cured ham

To evaluate the food safety effect of NaCl-free processing, acidification, smoking and high pressure in QDS processed^® dry-cured ham, 3 ham types (non-acidified smoked, acidified, and acidified smoked) were produced according to a standard (-S) and a new NaCl-free (-F) process. Slices were spiked with Listeria monocytogenes and Salmonella enterica (three strains each, <2 log CFU/g), dried by the QDS process^®, vacuum packed, high pressure treated at 600 MPa and stored under refrigeration for 112 days. Results of the challenge test showed that L. monocytogenes could only be eliminated from acidified smoked (AS) -S and -F processed ham slices at the end of storage, while S. enterica was present in all non-pressurized slices. The safest hams were those pressurized, especially AS-S hams, where L. monocytogenes was eliminated from 25 g of product immediately after HP treatment and S. enterica after 14 days. Compared with standard processing, NaCl-free processing showed lower levels of pathogens in non-pressurized slices but their elimination was delayed in pressurized ham slices.     

The economic growth enigma revisited: The EU-15 since the 1970s

Current macro-econometric models mostly incorporate just two factors of production, labour and capital (with a time-dependent multiplier representing technological change or total factor productivity). These models assume that energy is an intermediate product of some combination of human labour and capital. These models also assume that the supply of energy is driven by economic demand. We assume the contrary, i.e. that useful energy is a primary input, derived (mostly) from natural capital. This failure to capture the impact of primary resources (as useful energy) on economic growth leads to inappropriate formulation of economic growth theories. To understand that impact better we need explicit evidence of marginal products of capital, labour and useful energy or useful work. As applied to the explanation of the past half century of economic growth of the EU-15 countries, the new results demonstrate the use of non-parametric relationships between capital, labour and useful energy to explain economic growth. They also indicate that marginal products of capital, labour and useful energy are variable – the marginal product depends on the levels of capital stock, labour input and useful energy flows. The proposed semi-parametric production function suggests country-specific policy implications for the EU (and other countries).     

Simplified speciation and atmospheric volatile organic compound emission rates from non-aerosol personal care products

Volatile organic compounds (VOCs) emitted from personal care products (PCPs) can affect indoor air quality and outdoor air quality when ventilated. In this paper, we determine a set of simplified VOC species profiles and emission rates for a range of non-aerosol PCPs. These have been constructed from individual vapor analysis from 36 products available in the UK, using equilibrium headspace analysis with selected-ion flow-tube mass spectrometry (SIFT-MS). A simplified speciation profile is created based on the observations, comprising four alcohols, two cyclic volatile siloxanes, and monoterpenes (grouped as limonene). Estimates are made for individual unit-of-activity VOC emissions for dose-usage of shampoos, shower gel, conditioner, liquid foundation, and moisturizer. We use these values as inputs to the INdoor air Detailed Chemical Model (INDCM) and compare results against real-world case-study experimental data. Activity-based emissions are then scaled based on plausible usage patterns to estimate the potential scale of annual per-person emissions for each product type (eg, 2 g limonene person⁻¹ yr⁻¹ from shower gels). Annual emissions from non-aerosol PCPs for the UK are then calculated (decamethylcyclopentasiloxane 0.25 ktonne yr⁻¹ and limonene 0.15 ktonne yr⁻¹) and these compared with the UK National Atmospheric Emissions Inventory estimates for non-aerosol cosmetics and toiletries.     

中国与“一带一路”沿线国家农产品贸易的虚拟水流动研究

随着商品贸易,商品中所隐含的虚拟水也随之发生了转移。基于中国与“一带一路”沿线国家农产品贸易数据,测算2001、2007、2013、及2019年农产品贸易虚拟水量,分析中国与“一带一路”沿线地区虚拟水流动格局,通过位序-规模法及分形理论对各伙伴国贸易规模及空间分布发展进行研究以此来探究其垄断性及依赖性。结果表明：2001—2019年期间中国净进口“一带一路”沿线国家虚拟水量由83亿m3增至875亿m3,净出口国家数量由7个增加至27个,空间分布向均衡发展,位居前列的国家对中国的垄断性有所减弱;净出口量由33亿m3增至45亿m3,净进口国家数量由58个减少到47个,空间分布向集中发展,位居前列的国家对中国的依赖性增强;中国净进口的虚拟水类型以绿水为主,平均每年占比85.93%,主要来自于东南亚、南亚和东欧等地区;中国净出口的虚拟水类型以绿水和灰水为主,平均每年占比65.03%和24.07%,主要出口至非洲、西亚等地区;南亚、东欧、中亚、非洲及南欧由净进口区转变为净出口区;东亚仍为净进口地区。     

某金矿氟石膏基新型膏体充填材料配比试验研究

基于目前水泥胶凝材料价格大幅上调导致膏体充填成本高昂的实际境况,为降低充填成本,以工业废弃氟石膏为主要研究对象进行相关研究。利用氟石膏代替水泥,结合废石、粉煤灰、生石灰等掺加料,并辅以一定量的添加剂,开展氟石膏基新型膏体充填材料配比试验研究。通过坍落度、扩展度等试验确定材料的最优配比,并对膏体进行单、三轴及SEM试验,分析其宏微观结构。研究结果表明：质量浓度增大0min至120min,坍落度、扩展度损失率随之增大,泌水率却逐渐减小;最优配比所制成氟石膏基膏体的单轴压缩应力—应变曲线属于弹塑性曲线,最高可达6~7MPa;单轴与三轴压缩试验后,膏体表面未出现大的破裂面,且随围压的增加,应力—应变曲线不再出现峰值应力;所制充填材料的水化物主要包括钙矾石（AFt）、水化硅酸钙凝胶（C-S-H凝胶）和二水硫酸钙（CaSO4?2H2O）。氟石膏基新型膏体充填材料的配制具有深远的影响,为实现高效安全、绿色可持续的矿山开采提供了保障。