塑料包装材料存在的安全隐患及对策

随着塑料被广泛应用于食品及其他产品的包装,塑料包装材料的安全性已成为食品安全不可分割的重要组成,与我们的生活息息相关。本文以有关塑料包装材料的相关文献为基础,针对塑料基材、加工助剂、油墨等影响塑料包装材料安全性的因素进行了分析,并提出了建议和措施,解决塑料包装材料安全隐患。     

塑料包装材料的正确选择与合理使用—不同塑料包装对物品保质期的影响

本文阐述了塑料包装材料正确选择与合理使用的必要性，着重表明不同塑料对包装内容物保质期的影响，并提出加强塑料包装材料标准工作的建议。     

基于油墨附着性能的塑料软包装材料印刷适性分析

分析了油墨的附着性能及其对常用的软包装材料-塑料印刷效果的影响,提出通过对塑料材料进行预处理来改善油墨的附着性能实现高品质的塑料包装印刷.     

玄武岩纤维表面改性对生物膜附着性能的影响

采用壳聚糖对玄武岩纤维(BF)进行表面改性处理,研究改性后玄武岩纤维对生物膜附着性能的影响。利用红外光谱、X射线光电子谱仪、扫描电镜等对改性前后玄武岩纤维的表面官能团、成分和形貌进行表征分析,通过接触角测量仪对样品的亲水性进行研究,最后通过挂膜实验,讨论生物膜在改性前后玄武岩纤维上的附着性能。结果表明:采用物理涂覆法可成功制备改性玄武岩纤维(MBF),所制得的MBF表面粗糙度为209.04nm,接触角为66.62°。MBF表面形成的生物膜均匀致密,生物膜附着量明显增大,挂膜率由(129.27±1.23)%增加至(179.92±2.63)%,说明壳聚糖改性玄武岩纤维可以有效提升生物膜的附着性能。     

塑料包装对药品质量和安全性能的影响及解决措施

聚乙烯、聚氯乙烯、聚苯乙烯、聚丙烯等是药品包装常用塑料,其性能存在一些缺陷,影响着所包装药品的质量与安全性能。其影响因素主要有:塑料对药物的吸附作用,塑料添加剂向药物的迁移,聚合物单体的分解,材料的透气透湿性能等。可采取科学选择药品包装材料、大力推广使用医用环保增塑剂、推行医用塑料包装市场准入制度、严格控制药品流通环境安全等解决措施,以降低塑料包装对药品质量与安全性能造成的消极影响。     

塑料包装废弃物回收处理途径及新进展

商品的增多也带来了包装废弃物的增多,在这些包装废弃物中,塑料材料占到了首位。只有将这些塑料包装的废弃物回收处理或再生利用,才能解决这些废弃物给周围环境带来的污染问题。其实塑料的可回收利用率是很高的,再生塑料比再生纸的能耗要低30％。     

啤酒塑料包装现状和研发趋势

论述了国内外啤酒塑料包装研究开发的现状和发展趋势,其中涉及到许多高新塑料包装材料,展望了啤酒塑料包装的市场前景,提出了塑料啤酒瓶是啤酒包装的主流方向,对啤酒实施塑料化包装,具有较高的经济效益和社会效益.     

液态树脂基材料与铜基材料的界面润湿现象分析

采用静滴法观察了液态树脂基材料与铜基材料的界面润湿现象,测定了298～363 K温度范围内的接触角,计算了附着功.结果表明:接触角随时间呈下降趋势,基板表面粗糙度对接触角的影响较大,在表面粗糙度较小时,接触角随时间下降较快,平衡接触角较小;初始接触角和平衡接触角均随树脂基材料中环氧树脂含量的增加而降低;升高温度使接触角的变化速率加快,加入树脂后的液体的平衡接触角对温度更加敏感;附着功随着时间的延长逐渐增加,但随着温度的上升而减小.     

塑料包装材料与食品安全

二十世纪合成树脂材料的不断开发和工业化,使得塑料包装材料获得了空前的发展,塑料食品包装应用极其广泛。从生鲜食品到即拜熟食,从单体包装到运输包装,从固体到液态,覆盖了食品生产加工销售的整个产业链;包装形式有托盘、容器、软管、编织袋、单层、多层薄膜等等;使用塑料包装时的条件各异,有冷藏,也有微波加热、高温蒸煮等;包装的内容物种类成分繁多;塑料品种多,制品化学成分极其复杂。     

21世纪初世界塑料包装材料发展展望

本文扼要介绍了世界塑料包装材料的发展概况,重点对21世纪初世界塑料包装材料的发展趋向进行展望,并分析评述了塑料包装和环保的关系。一、世界塑料包装材料发展概况及预测90年代以来,尽管塑料包装材料一直经受环境问题的严重挑战,但从近年来发表的数据来看,塑料包装在包装工业中仍成为需求增长最快材料之一。据美国Freedonia集团的统计分析和预测,美国包装领域中纸和塑料1987－1996年间合计年平均增长率为1．5％,其中纸和纸板为-0．4％,塑料为4．4％;1996－2001年间合计年平均增长率为2．4％,其中纸和纸板为1．6％,塑料为3．4…     

基于g–C3N4光催化型抗菌包装纸的制备及其抗菌性研究

目的 解决g–C3N4存在的比表面积小，电子–空穴复合速率快从而导致光催化性能不佳等问题。方法 以尿素和硫脲为前驱体材料，通过热解聚辅助水蒸气活化合成S掺杂石墨相氮化碳(g–C3N4)，并用界面聚合制备出光催化型抗菌包装纸。利用扫描电镜(SEM)、红外光谱(FTIR)、水接触角(WCA)、热重分析(TGA)、光催化抗菌实验等对抗菌包装纸的形态结构、表面官能团、纸张性质、光催化抗菌性进行详细研究。结果 致密的g–C3N4层有效提高了抗菌包装纸的疏水性和热稳定性。可见光照射下，光催化型抗菌包装纸对大肠杆菌和金黄色葡萄球菌的杀灭率达100%。未经可见光照射的原纸比光催化型包装纸的抗菌性差。结论 g–C3N4光催化型抗菌包装纸具有良好的广谱抗菌性，为绿色抗菌包装材料的制备提供了新思路。     

Recyclable mono materials for packaging of fresh chicken fillets: New design for recycling in circular economy

The focus on sustainability and circular economy is leading to a need for development of new food packaging concepts, including recyclable materials that ideally consist of a single material in a monolayer system. This research was focused on the possibility of replacing complex multilayered material [amorphous polyethylene terephthalate/polyethylene (APET/PE)] with simple recyclable mono material [high-density polyethylene (HDPE)] for packaging of chicken fillets in modified atmosphere packaging (CO₂/N₂: 60%/40%). Bacterial growth measured as total viable count (TVC), lactic acid bacteria and Enterobacteriaceae, Brochothrix thermosphacta and Escherichia coli for chicken fillets packed in HDPE mono materials was compared with chicken fillets packed in APET/PE. TVC increased during the storage period (24 days) with high level of TVC count (7 log₁₀ CFU/g) recorded at Days 19–20 of storage in both HDPE and APET/PE material. No significant differences were recorded in off-odour between chicken stored in APET/PE compared with HDPE in CO₂/N₂ atmosphere during the storage period (samples were regarded as acceptable on the 24th day of storage). The drip loss increased in all samples during storage, and no significant differences between samples stored in different materials were recorded. Significant differences in bacterial growth were recorded between samples with different gas volume to product volume (G/P) ratio (Day 17), implying that higher G/P ratio is resulting in lower TVC count. The lowest G/P ratio caused the highest drip loss, whereas addition of CO₂ emitter reduced the drip loss to some extent. This research is very encouraging as it provides new insight into the use of monolayer materials as well as the importance of design for recycling in circular economy.     

Novel pineapple leaf fibre composites coating with antimicrobial compound as a potential food packaging

Biodegradable packaging coated with antimicrobial compounds has emerged as a new type of food packaging with potential to enhance food safety, extend shelf life and minimize plastic pollution. We have developed a polylactic acid (PLA) composite pineapple leaf fibre (PALF) biopolymer to fulfil the high demand of biodegradable materials for a potential use in food packaging. Our formulation with 10% pineapple fibre PLA/PALF composites exhibited enhanced melting temperatures and heat resistance, with a 44% reduction in the tensile strength and 2.7-fold reduction on the strain at the break when compared with neat PLA. To impart antimicrobial activity, the PLA/PALF was coated with crude supernatants isolated from Pediococcus pentosaceus PP04 containing 1.3% w/v of nisin. This material coated with the crude extract was shown to inhibit the growth of Bacillus cereus ATCC 11778, Salmonella enterica subsp. enterica serovar Typhimurium ATCC 13311, and Escherichia coli ATCC 8739 in culture conditions, as well as minimizing the number of the tested pathogens on coated material surfaces.     

基于神经网络的塑料打包带高光谱模式识别

目的 建立一种快速、准确、无损的塑料打包带的检验及分类方法。方法 利用高光谱在波长为350～990 nm的条件下采集52个不同来源的塑料打包带样品的高光谱数据,并对样品进行Savitzky-Golay平滑处理,同时结合主成分分析对样品进行降维。将提取到的主成分进行K-Means聚类,以聚类结果为依据建立径向基函数神经网络（RBFNN）与BP神经网络模型（BPNN）。结果 打包带样品的高光谱谱图在400～500 nm、600～700 nm处有较大区别。实验共提取了5个初始特征值大于1的主成分,可以解释96.633%的原始数据。通过K-means聚类将塑料打包带样品分为6类,Calinski-Harabasz指数为28.76,RBFNN分类准确率为86.7%;BPNN分类准确率为98.1%,BPNN的分类效果更好。结论 研究表明神经网络在高光谱谱图分类处理上具有较高的准确度,同时也验证了高光谱在区分检验塑料打包带类物证的可行性与科学性,为公安机关提供了一种新的检验方法。     

Preservation of sliced ham through triclosan active film

Active packaging is an alternative to preserve perishable food. In this work, polyethylene antimicrobial active films containing different levels of triclosan (0, 2000 and 4000 mg kg^?1) were developed by extrusion. The films' efficacies were evaluated against Escherichia coli, Staphylococcus aureus, Listeria innocua, Salmonella choleraesuis and Pseudomonas aeruginosa growth using agar diffusion test and by monitoring the inhibition of E. coli and S. aureus inoculated on sliced cooked ham. The mechanical characteristics of the films were also evaluated with Universal Test Machine (Instron). The incorporation of triclosan did not affect the mechanical properties of antimicrobial films compared to the control film. The average film thickness was 82.0 µm and the tensile strength and elongation to break were 30.3 N and 46.2%, respectively. Films containing triclosan showed an antimicrobial effect in vitro against E. coli and S. aureus, with formation of an inhibition halo for both. However, this result was not observed for L. innocua, S. choleraesuis and P. aeruginosa, although, a decrease in colony density occurred around the film for both incubation temperatures (7 ± 2°C and 35 ± 2°C). Sliced ham packed with the antimicrobial films showed a reduction of 1.5 logarithmic cycles in comparison to ham in contact with a control film after 12 days of storage at 7 ± 2°C, for E. coli and S. aureus. Antimicrobial films present potential for application as active packaging materials, as they showed effective against some pathogenic microorganisms that can be transmitted by foods. Copyright © 2009 John Wiley & Sons, Ltd.     

薄膜包装对娃娃菜采后贮藏品质的影响

目的探究适用于娃娃菜采后贮藏保鲜的包装材料。方法采用4种不同厚度的聚乙烯薄膜(10,20,30,40μm)包装娃娃菜,以市场销售的原包装薄膜为对照,测定在常温(23±2)℃下贮藏28 d的品质变化,之后以筛选出的薄膜材料为研究对象,进一步分析其对娃娃菜采后贮藏品质的影响。结果与其他薄膜包装相比,厚度为30μm的聚乙烯薄膜包装材料对娃娃菜的保鲜效果最好,其可溶性糖、蛋白含量分别为13.49 mg/g,3.79 mg/g,MDA的质量摩尔浓度为1.51μmol/g。与对照组相比,厚度为30μm的薄膜包装能够有效抑制娃娃菜表面菌落总数的生长,延迟腐烂现象的发生,维持其组织较高的抗坏血酸、总酚、可溶性糖、总硫苷和萝卜硫素含量。主成分法综合评价的结果也显示,厚度为30μm的薄膜包装对减缓娃娃菜品质劣变的效果更理想。结论厚度为30μm的聚乙烯薄膜包装能更好地维持采后娃娃菜的贮藏品质,适宜用作采后娃娃菜的包装贮运材料。     

Corona Discharge Plasma Jet Inactivates Food‐borne Pathogens Adsorbed onto Packaging Material Surfaces

The potentiality of corona discharge plasma jet (CDPJ) for disinfection of food packaging materials, including glass, polyethylene, polypropylene, nylon and paper foil, was evaluated. CDPJ was generated using a high voltage (20 kV) pulsed DC power source, at 1.5 A current and 58 kHz frequency. The separation distance between plasma electrode and sample plate during the treatment was 25 mm. Upon treating food pathogens‐loaded packaging materials by the plasma, 4.5–5.0 log/cm² reductions (99.999%) in viable cell counts of Escherichia coli O157:H7 and Staphylococcus aureus were observed in 120 s. Another tested pathogen Salmonella Typhimurium was inactivated by 3.0 log/cm² units. The patterns of inactivation of pathogens are fitted well to Weibull tail model. Compared to untreated controls, the CDPJ‐treated packaging materials exhibited insignificant (p > 0.05) changes in the optical characteristics, tensile strengths, surface temperatures and strain‐induced deformation. Therefore, the most common food packaging materials harboring bacterial pathogens could be disinfected by the CDPJ without compromising physicomechanical properties of materials. Copyright © 2017 John Wiley & Sons, Ltd.     

Chitosan‐based nanofibers as bioactive meat packaging materials

Shelf life and safety of minimally processed food are crucial for both consumers and the food industry. This study investigates the in vitro and in situ efficiency of electrospun chitosan‐based nanofibers (CNFs) as inner part of a multilayer packaging in maintaining the quality of unprocessed red meat. Activated CNF‐based packaging (CNFP) were obtained by direct electrospinning of chitosan/poly(ethylene oxide) solutions on top of a conventional multilayer food packaging. The electrospinning solutions were firstly characterized at the molecular level, mainly in terms of zeta potential and viscoelastic properties, and the evolution of the conformational structure was correlated to the nanofiber formation process. The oxygen and water vapor barrier properties of CNF‐based (CNFP) meat packaging were also investigated. The in vitro antibacterial activity of CNFs was determined against Escherichia coli, Salmonella enterica serovar Typhimurium, Staphylococcus aureus, and Listeria innocua, bacteria commonly incriminated in the alteration of food products. The efficiency of the CNFP materials against meat spoilage by E. coli was also assessed. Our results indicate that the electrospinning of CS is a multifactorial process and fiber formation requires the choice of a good solvent, high electrical conductivity, moderate surface tension, optimum viscoelastic properties, and sufficient chain flexibility and entanglement. The results also indicate that all the tested bacterial strains were significantly sensitive to the action of CNFs. The in situ bioactivity against E. coli showed the potential of CNFP as bioactive nanomaterial barriers to meat contamination by extending the shelf life of fresh meat up to 1 week.     

Effect of packaging materials and storage conditions on bacterial growth,off‐odour,pH and colour in chicken breast fillets

A comparison was made of the effect of different packaging materials on bacterial growth, off‐odour, pH and colour of chicken breast fillets stored at 4°C. For one of the packaging materials, the effects of temperature (4°C and 8°C) and initial oxygen present (0%, 2% and 4%) on bacterial growth, off‐odour, pH and colour in chicken breast fillets were also evaluated. Chicken breast fillets stored in the packaging material with the highest oxygen transmission rate (OTR) measured at actual storage conditions had the highest bacterial growth and the highest degree of off‐odour. Chicken breast fillets stored in packaging material mainly consisting of expanded PET had similar bacterial growth and off‐odour as in the barrier display film (BDF) packages, despite a smaller headspace volume and lower initial concentration of CO₂. No differences in discoloration and pH of the chicken breast fillets, due to storage temperature and amount of initial oxygen present, were found when one of the packaging materials was studied. In the early phase of the storage period, Pseudomonas spp. constituted the majority of the total viable counts, while after about 12 days, lactic acid bacteria dominated. At the end of the storage period, both Pseudomonas spp. and Enterobacteriaceae were present in high numbers. Significant differences in counts of Brochothrix thermosphacta were only obtained with initial presence of oxygen. The storage temperature had greater impact on microbial growth and off‐odour than the initial presence of oxygen in the packages. Copyright © 2004 John Wiley & Sons, Ltd.