Migration studies and chemical characterization of low molecular weight cyclic polyester oligomers from food packaging lamination adhesives

Laminate structures are widely used for food packaging applications. Polyester urethane‐based adhesives are very common materials for bonding the layers of such laminates together. Unintended by‐products of polyester synthesis include low molecular weight cyclic polyester oligomers (cyclic oligoesters) that lack the required hydroxyl functionality to react with isocyanates to form the intended high molecular weight polyurethane polymer and remain as impurities with high migration potential. Our investigation conducted migration studies of 537 commercial and/or developmental food packaging laminate structures by using food simulants with gas chromatography‐mass spectrometry analyses of the extracts. A subset of the extracts were also analysed by high‐performance liquid chromatography‐mass spectrometry and gas chromatography‐mass spectrometry with chemical ionization. Migration of cyclic oligoesters of diverse chemical structure was observed in nearly all of the samples analysed. Aside from migrants originating directly from polyolefin sealant films on the food‐contact side of the laminates, cyclic oligoesters were the migrants detected at next highest concentration. This report presents electron ionization mass spectra and molecular structures of 106 cyclic oligoesters including a series of novel as well as previously identified species. Fifty‐six cyclic oligoesters migrated from the 537 laminate samples analysed were evaluated for frequency of occurrence and migration concentration range. The most commonly observed cyclic oligoester migrants were those derived from combinations of the polyhydric alcohols, diethylene glycol, and neopentyl glycol and the dibasic acids, adipic, and phthalic/isophthalic.     

Migration of di‐(2‐ethylhexyl)adipate (DEHA) and acetyl tributyl citrate (ATBC) plasticizers from PVC film into the food stimulant of isooctane

Chemical migration from food packing is influenced by several factors such as nature of chemicals, complexity of food, temperature, packing material used and properties of the migrating substances. Chemical compounds that are incorporated within polymeric packaging materials may interact with food components during processing or storage and migrate into the food by jeopardizing the food safety. This migration is higher if food remains in contact with packing material for extended time. Polyvinyl chloride (PVC) film such as di‐(2‐ethylhexyl) adipate (DEHA) and acetyl tributyl citrate (ATBC) are still widely used as a food packing material due to its flexibility, transparency and low water permeability. The present study covers the main migration phenomena of both plasticizers (di‐(2‐ethylhexyl) adipate (DEHA) and acetyl tributyl citrate (ATBC)) from PVC‐film into isooctane food stimulant using a direct gas chromatographic method. An exposure period of 48 h at 30 °C and 4 °C was used. The obtained results showed DEHA levels ranging of 7.2 mg/dm² while, no ATBC migration from PVC‐film was observed. Results are discussed in relation to EU legislation proposed upper limit for DEHA specific migration (18 mg/L or 3 mg/dm²) and overall migration limit (OM) of 10 mg/dm².     

淀粉基塑料购物袋性能表征研究

目的 通过对淀粉基塑料购物袋的理化性能表征,了解淀粉基塑料购物袋使用特性,为改善淀粉基塑料购物袋使用性能提供一些理论依据。方法 采用热重分析(TG)、热机械分析(TMA)等手段对淀粉基塑料购物袋的淀粉含量及耐热性能进行分析,借助电子万能材料试验机对淀粉基塑料购物袋的力学性能进行分析,以及利用霉菌培养、总迁移行为探究等方法对淀粉基塑料购物袋霉变程度、卫生性能进行分析。结果 样品A、B、C淀粉质量分数分别为15.72%、23.97%、30.36%,耐热性能比传统PE塑料袋要低;淀粉基塑料购物袋的拉伸强度随淀粉含量的增大而减小,断裂伸长率随淀粉含量的增加而增加,总迁移量结果随淀粉含量增加而增大,但经三氯甲烷处理后均低于限量要求;淀粉基塑料购物袋不适宜盛装酸性和低乙醇类食品。结论 通过对淀粉基塑料购物袋深入研究,发现淀粉基塑料购物袋在力学性能、总迁移量、霉变程度存在缺陷,望研究者们可以从这几个方向入手,改善淀粉基塑料购物袋的理化性能。     

Determination of Four Types of Hazardous Chemicals in Food Contact Materials by UHPLC‐MS/MS

A simple ultrahigh‐performance liquid chromatography (UHPLC) tandem mass spectrometric method for the identification and quantification of two photoinitiators 4‐methylbenzophenone and 2‐ethylhexyl‐4‐dimethylaminobenzoate; nine plasticizers including di(2‐ethylhexyl) adipate and diisobutyl adipate; three primary aromatic amines 4‐aminobiphenyl, 4‐amino‐2′,3‐dimethylazobenzene and bis‐(4‐aminophenyl) methane and six bisphenols bisphenol F diglycidyl ether, bisphenol A diglycidyl ether, bisphenol A (BPA), bisphenol B (BPB), bisphenol E (BPE) and bisphenol F (BPF) in food contact materials has been developed. The chromatographic conditions, pre‐treatment methods and matrix effects were studied and optimized. For the determination of the four bisphenols, BPA, BPB, BPE and BPF, the UHPLC method employed a mobile phase of aqueous ammonia and methanol in binary gradient mode, and measurement was based on a triple quadrupole mass spectrometer equipped with an electrospray ionization (ESI) source operating in negative ion mode. The remaining chemicals were determined using the ESI source in positive ion mode and using the [M + NH₄]⁺ or [M + H]⁺ adducts as precursor ions for tandem mass spectrometry. The calibration graphs were linear with correlation coefficients of above 0.995. Detection limits for the method were in the range of 1–16 µg/kg. Analyte recovery values were in the range of 70–114%, and relative standard deviations were 1–14%. Under optimized conditions, the chromatographic separation was performed in 12 min. The validation data indicated that the method was effective for the determination of the four classes of hazardous chemicals in plastic packaging materials or in can lacquers. The optimized method was successfully applied to trace analysis of commercially available food contact materials. Copyright © 2014 John Wiley & Sons, Ltd.     

HPLC-MS/MS法测定食品接触材料中6种邻苯二甲酸酯的含量

建立了测定食品接触材料中6种邻苯二甲酸酯的含量的高效液相色谱-串联质谱法(HPLC-MS/MS)。实验以Agilent ZORBAX SB-C18色谱柱为分析柱,以甲醇-0.1%的甲酸水为流动相,采用梯度模式洗脱。质谱离子源的工作模式为正离子电离模式(ESI+),流速为0.35 mL/min,采用多反应监测离子模式(MRM)进行检测定量。实验样品前处理采用了加速溶剂萃取法,明显提高了食品接触材料中邻苯二甲酸酯的提取效率。结果表明:6种邻苯二甲酸酯在其线性范围内线性关系良好(R2>0.999),DPRP和BBP的定量限为1.0 ng/mL,DCHP,DNHP,DHP,DBEP的定量限为0.2 ng/mL,DPRP和BBP的检测限为0.2 ng/mL,DCHP,DNHP,DHP,DBEP的检测限为0.05 ng/mL。该方法的加标回收率为89.2%～107.5%,相对标准偏差均小于5.0%。实验表明,所建立的方法简单、灵敏度高,适用于食品接触材料中的6种邻苯二甲酸酯类增塑剂的分析检测。     

Comparison of three coupled gas chromatographic detectors (MS, MIP-AES, ICP-TOFMS) for organolead speciation analysis

An automatic unit for the screening of rainwater is used for the determination of organolead compounds using different detectors coupled to a gas chromatograph. A systematic overview is given of the advantages and disadvantages of several detectors (electron ionization mass spectrometry, EI-MS; microwave induced plasma atomic emission spectrometry, MIP-AES; and inductively coupled plasma time-of-flight mass spectrometry, ICP-TOFMS, for the speciation of organolead compounds on the basis of sensitivity, selectivity and reliability. C60 fullerene and RP-C18 were used as sorbent materials for these compounds. The primary assets of the fullerene sorbent, as compared to C18 sorbent, are high sensitivity and selectivity resulting from efficient adsorption due to large surface area and interstitial volume. Among the detection systems, GC/ ICP-TOFMS is the most sensitive, with absolute detection limits of approximately 15 fg of organolead compounds (as lead) using 5-mL sample volumes. Except for diethyllead, similar sensitivities were obtained by MIP-AES. GC/MS is intrinsically the most specific option, because the species are detected directly from molecular information. The precision is similar for all detectors. The screening of rainwater from different locations showed that samples collected in countries in which leaded gasolines are now banned contain organolead species at concentrations below 2 pg/ mL, levels that can be detected only for sample volumes of 25 mL and using MIP-AES or ICP-TOFMS as detectors, their determination being impossible by GC/MS.     

Boron Embedded in Metal Iron Matrix as a Novel Anode Material of Excellent Performance

Boron, the most ideal lithium‐ion battery anode material, demonstrates highest theoretical capacity up to 12 395 mA h g^?1 when forming Li₅B. Furthermore, it also exhibits promising features such as light weight, considerable reserves, low cost, and nontoxicity. However, boron‐based materials are not in the hotspot list because Li₅B may only exist when B is in atomically isolated/dispersed form, while the aggregate material can barely be activated to store/release Li. At this time, an ingenious design is demonstrated to activate the inert B to a high specific capacity anode material by dispersing it in a Fe matrix. The above material can be obtained after an electrochemical activation of the precursors Fe₂B/Fe and B₂O₃/Fe. The latter harvests the admirable capacity, ultrahigh tap density of 2.12 g cm^?3, excellent cycling stability of 3180 mA h cm^?3 at 0.1 A g^?1 (1500 mA h g^?1) after 250 cycles, and superlative rate capability of 2650 mA h cm^?3 at 0.5 A g^?1, 2544 mA h cm^?3 at 1.0 A g^?1, and 1696 mA h cm^?3 at 2.0 A g^?1. Highly conductive matrix promoted reversible Li storage of boron‐based materials might open a new gate for advanced anode materials.     

包装材料对肉类食品胀袋问题的影响与分析

目的 比较分析不同种类包装材料的性能差异对所包装肉类食品胀袋问题的影响。方法 以常见的用于包装烧鸡的PA/Al/CPP、BOPA/LDPE,包装猪蹄的PET/PA/CPP、PET/PA/Al/CPP,包装肉肠的PVDC共挤膜、BOPP/PVDC/PE等6种材料为试验样品,分别测试其揉搓前后氧气透过量、拉伸性能、抗穿刺性能、热封强度、密封性能。结果 样品阻隔性由高到低依次为PET/PA/Al/CPP、PA/Al/CPP、PVDC共挤膜、BOPP/PVDC/PE、PET/PA/CPP、BOPA/LDPE;揉搓后PET/PA/Al/CPP阻隔性仍较高,PA/Al/CPP耐揉搓性差,出现贯穿性针孔,揉搓前后BOPA/LDPE、PET/PA/CPP的阻隔性相差不大;BOPP/PVDC/PE拉伸性能较差,横向断裂伸长率仅为28.4%,且热封强度低,其余样品的拉伸性能、抗穿刺性能、热封强度均较好;PA/Al/CPP,BOPP/PVDC/PE成品包装分别在袋体折皱处、袋体与热封口处漏气,其余样品均未漏气。结论 耐揉搓性差、拉伸性能差及热封强度低分别是烧鸡PA/Al/CPP包装、肉肠BOPP/PVDC/PE包装发生胀袋的主要原因;阻氧性偏低易导致由BOPA/LDPE,PET/PA/CPP,PVDC 5层共挤膜包装的烧鸡、猪蹄、肉肠在长时间存储时缓慢胀袋。上述样品存在的问题主要与材质结构、铝箔层质量、材料生产及热封工艺有关。     

Influence of packaging material on bread characteristics during ageing

One of the priorities of today's bread‐making industry is to find suitable packaging solutions to satisfy the peculiar requirements of bread, mostly appreciated by Italian consumers for its crispy crust. The packaging material should allow for both rapid heat exchange with the environment and water vapour evaporation to prevent condensation inside the package. Perforated orientated polypropylene (OPP) films are currently the best materials available for satisfying the industry's requirements. Recently, our group demonstrated that bread wrapping with perforated films is efficacious against bread contamination. The aim of this work was to verify whether these types of films could also influence the trend of phenomena related to product ageing. In particular, variations in the moisture inside the loaf during storage and their influence on changes in crumb softness were investigated. Three OPP films and one double‐layer film bag with different hole size characteristics were chosen for this study and their performances were compared with those of a paper bag. Because of the considerable differences in the hole size characteristics, the films showed very different barrier effects to water evaporation. The C250 OPP film (hole mean diameter = 0.54 mm and density = 21.4 holes/cm²) played an interesting role in modulating moisture variations. Wrapping bread in this film enabled both crust crispness and crumb softness to be maintained during 48h of storage. Such performances cannot effectively be obtained by using alternative industrial bread packaging materials, such as paper bags. Copyright © 2006 John Wiley & Sons, Ltd.     

Structure and properties of ultrafine silk fibers produced by <Emphasis Type="Italic">Theriodopteryx ephemeraeformis</Emphasis>

Theriodopteryx ephemeraeformis commonly known as bag worms produce ultrafine silk fibers that are remarkably different than the common domesticated (Bombyx mori) and wild (Saturniidae) silk fibers. Bag worms are considered as pests and commonly infect trees and shrubs. Although it has been known that the cocoons (bags) produced by bag worms are composed of silk, the structure and properties of the silk fibers in the bag worm cocoons have not been studied. In this research, the composition, morphology, physical structure, thermal stability, and tensile properties of silk fibers produced by bag worms were studied. Bag worm silk fibers have considerably different amino acid contents from those of the common silks. The physical structure of the bag worm silk fibers is also considerably different compared with B. mori and common wild silk fibers. Bag worm’s silk fibers have lower tensile strength (3.2 g/denier) and Young’s modulus (45 g/denier) but similar breaking elongation (15.3%) compared with B. mori silk. However, the tensile strength and Young’s modulus of bag worm fibers are similar to those of the common Saturniidae wild silk fibers. Bag worm silk fibers could be useful for some of the applications currently using the B. mori and wild silk fibers.     

Sampling of trace volatile metal(loid) compounds in ambient air using polymer bags: a convenient method

The sampling of volatile metal(loid) compounds (VOMs) such as hydrides, methylated, and permethylated species of arsenic, antimony, and tin is described using Tedlar bags. Advantages as well as limitations and constraints are discussed and compared to other widely used sampling techniques within this area, namely, stainless steel canisters, cryotrapping, and solid adsorbent cartridges. To prove the suitability of Tedlar bags for the sampling of volatile metal(loid) compounds, series of stability tests have been run using both laboratory synthetic and real samples analyzed periodically after increasing periods of storage. The samples have been stored in the dark at 20 degrees C and at 50 degrees C. Various volatile arsenic species (AsH3, MeAsH2, Me2AsH, Me3As), tin species (SnH4, MeSnH3, Me2SnH2, Me3SnH, Me4Sn, BuSnH3), and antimony species (SbH3, MeSbH2, Me2SbH, Me3Sb) have been generated using hydride generation methodology and mixed with moisturized air. Three static gaseous atmospheres with concentrations of 0.3-18 ng/L for the various compounds have been generated in Tedlar bags, and the stability of the VOMs has been monitored over a period of 5 weeks. Sewage sludge digester gas samples have been stored only at 20 degrees C for a period of 48 h. Cryotrapping GC/ICPMS has been used for the determination of the VOMs with a relative standard deviation of 5% for 100 pg. After 8 h, the recovery rate of all the compounds in the air atmospheres was better than 95% at 20 and 50 degrees C, whereas the recovery after 24 h was found to be between 81 and 99% for all VOMs at 20 and 50 degrees C except for Me3Sb and Me3As. These species show a loss between 48 and 73% at both temperatures. After 5 weeks at 20 degrees C, a loss of only 25-50% for arsine and stibine and the above-mentioned tin compounds was determined. Only Me3Sb, Me3Bi, and Me2Te were present in the digester gas sample. After 24 h, losses of 44, 10, and 12%, respectively, could be determined. Given these results, Tedlar bags could even be used, with some limitations, for long-term sampling of air containing traces of VOMs. The loss is more pronounced at higher temperatures.     

An investigation of contact resistance between metal electrodes and amorphous gallium-indium-zinc oxide (a-GIZO) thin-film transistors

This paper reports our investigation of different source/drain (S/D) electrode materials in thin-film transistors (TFTs) based on an indium-gallium-zinc oxide (IGZO) semiconductor. Transfer length, contact resistance, channel conductance, and effective resistances between S/D electrodes and amorphous IGZO thin-film transistors were examined. Intrinsic TFT parameters were extracted by the transmission line method (TLM) using a series of TFTs with different channel lengths measured at a low drain voltage. The TFTs fabricated with Cu S/D electrodes showed the lowest contact resistance and transfer length indicating good ohmic characteristics, and good transfer characteristics with intrinsic field-effect mobility (μ_FE-i) of 10.0 cm²/Vs.     

Assessing Acute Toxicity of Selected Packages Internal Layers Extracts using Microtox®

In the scientific literature related to the widely understood issue of packaging materials designed to have contact with food (food contact materials), there is much information on raw materials used for their production, as well as their physiochemical properties, types and parameters. Unfortunately, not much attention is given to the issues concerning migration of toxic substances from packaging and its actual influence on the health of the final consumer, even though health protection and food safety are the priority tasks. The goal of this study was to estimate the impact of particular foodstuff packaging type, food production and storage conditions on the degree of leaching of potentially toxic compounds to foodstuffs with the use of the acute toxicity test Microtox^®. From all simulants studied, the 3% acetic acid in water proved to cause significant migration of toxic compounds with increase of time and temperature of extraction and justified the hypothesis that food products with low pH values (stored in cans) cause significant damage to cans internal resin filing and is a reason of increased migration rate of package material to foodstuff. Copyright © 2017 John Wiley & Sons, Ltd.     

Fluorine speciation analysis using reverse phase liquid chromatography coupled off-line to continuum source molecular absorption spectrometry (CS-MAS): identification and quantification of novel fluorinated organic compounds in environmental and biological samples

Driven by increasing demand for the monitoring of industrial perfluorinated compounds (PFCs), the identification of novel fluorine containing compounds (FOCs) and the tracking of organofluorine drugs and their degradation products, there is a clear need for sensitive, fluorine-specific detection of unknown FOCs. Here we report the first ever direct fluorine-specific (speciation) method; capable of individually detecting untargeted FOCs in environmental and biological samples through the application of continuum source molecular absorption spectrometry (CS-MAS) using a commercial CS-AAS. Two model FOCs (2,4,6, trifluorobenzoic acid (TFBA) and 5-fluoroindol-5-carboxylic acid (FICA)) were used, achieving fluorine-specific detection across a range of 0.1 to 300 ng/mL fluorine, corresponding to a limit of detection of 4 pg F and 5.26 nM for both compounds. Both TFBA and FICA showed a similar response to CS-MAS detection, potentially enabling the quantification of fluorine content in novel FOCs without having molecular standards available. This paper also reports the use of reverse-phase high performance liquid chromatography (RP-HPLC) coupled off-line with CS-MAS for the identification of single organofluorines in a mixture of FOCs via fraction collection. The linear range of both FOCs was determined to be from 1 to 500 ng/mL. The limits of detection of those species were just above 1 ng/mL (100 pg) and can therefore compete with targeted analytical methods such as ESI-MS. Finally, as a proof of principle the analysis of a fluoride-containing groundwater sample from Ghana demonstrated that this method can be used in the detection of novel FOCs, with identification achieved through parallel ESI-MS. Coupled HPLC-CS-MAS/ESI-MS is the first analytical methodology capable of selectively detecting and identifying novel FOCs, making possible the quantification of all fluorine containing compounds in one sample. This is the necessary analytical requirement to perform fluoronomics.     

Investigation of Cs(I) and Sr(II) removal using nanoporous bentonite

ABSTRACT

Bentonites are types of clays made up the dominant constituent of montmorillonite. Four types of nano-porous and nano-structured commercial bentonite clays were studied in detail for their physicochemical and mineralogical properties vs. Cs and Sr adsorption. The instrumental analyses to study samples were X-ray diffraction (XRD), X-ray fluorescence (XRF), Brunauer–Emmett–Teller (BET) surface area measurements, Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and thermogravimetry (TG). The XRF and peaks of XRD patterns at 2θ?=?8, 19.9, 35, 55, and 62 clearly indicated that the main component of the bentonite samples was montmorillonite. The BET analysis showed that B1 has the highest specific surface area among the other samples which its single and multiple point BET surface area were equal to 84.85 and 85.94?m²?g^?1, respectively. These values represents the amount of montmorillonite and adsorption capacity of samples. The physicochemical, structural and morphological characteristics of different samples were investigated through instrumental analysis. The results of separation processes of Cs(I) and Sr(II) showed 59.75 and 45.5% adsorption capacities for B3 and B2 which were the highest values among the others. The results lead to the conclusion that samples B3 had a good adsorption capacity to remove Cs(I) and Sr(II).     

Migration of Cyclic Monomer and Oligomers from Polyamide 6 and 66 Food Contact Materials into Food and Food Simulants: Direct Food Contact

Cyclic monomer and oligomers are the major migrating substances from polyamide (PA) food contact materials. An increase of caprolactam (+44%) and cyclic oligomer content (+27%, incl. caprolactam) in PA6 was observed by thermal treatment, here by extrusion of a PA6 film from a granulate. Migration experiments with a PA6 and a PA66 packaging film were carried out into food simulants according to directives 85/572/EEC and 82/711/EEC. Contact conditions (2 h/100°C) were chosen for a heat treatment of the food in the packaging, in this case production of scalded sausage. Aqueous and ethanolic food simulants clearly revealed to be the worst case for migration of cyclic PA6 and PA66 monomer and oligomers. Migration of cyclic oligomers into oil was one order of magnitude lower. No migration could be observed into isooctane (<8 µg dm^?2). The substitutes for oil, 95% ethanol and isooctane, were inapplicable for simulating migration of cyclic oligomers into oil. Caprolactam showed different migration behaviour compared with cyclic oligomers, migrating into oil and water to the same extent depending on contact conditions. Fifty percent of the extractable caprolactam migrated from a PA6 sausage casing into scalded sausage (4.2 mg kg^?1), residual 41% apparently were extracted by the boiling medium or during pretreatment (soaking) of the casing. Potential migration of caprolactam and cyclic oligomers from a PA6 tea bag was found to be 18% of the specific migration limit for caprolactam and 36% of the overall migration limit. Copyright © 2014 John Wiley & Sons, Ltd.     

Recovery of cesium ions from aqueous solutions with composite sorbents based on tripolite and copper(II) and nickel(II) ferrocyanides

Uptake of cesium ions from aqueous solutions with tripolite modified with nickel(II) and copper(II) ferrocyanides was studied. The composite sorbent based on tripolite and nickel(II) ferrocyanide exhibits the highest sorption-selective (K _d 1.6 × 10⁴ cm³ g^?1 against the background of 0.1 M NaCl) and kinetic properties among the samples studied. It efficiently takes up cesium ions from aqueous solutions, including salt-containing solutions.     

Bag-in-box packaging for wine: Analysis of transport stress in barrier films

This study was conducted on bag-in-box packages for wine to show how the transport stress changes the oxygen permeability of the bags and the possible consequences for the wine's shelf-life. Bags from five leading bag suppliers/film producers were tested. The bags were subjected to two types of transport stress–simulated vibration testing in the laboratory and actual road transport (1000 km) and the same type of corrugated fibreboard box was used throughout. During road transport a red French table wine was used. Emphasis was placed on leakage and O₂ permeability in the investigation of the bags. The study showed no visible bag leakage. Measurement of the O₂ permeability revealed that the bag with an Al-laminated barrier film had the lowest permeability. The ethylene vinyl alcohol (EVOH) bags were more permeable than the Al-laminated bags, while metallized polyester (Met. PET) had the highest O₂ permeability. Chemical analysis of the wine included the measurement of free and total SO₂, oxygen and colour, carried out 1, 4.5 and 9 months after filling. Sensory analysis was carried out as a series of rank order tests performed 5 and 9 months after filling. The chemical and sensory measurements showed small differences between the various bag types. Regarding wine quality, none of the tested bag types distinguished themselves either in a positive or a negative direction in relation to similar table wine stored in glass bottles. The analysis after 9 months of storage showed that none of the wines were oxidized to an unacceptable quality compared to the quality of the same wine stored in glass bottles (not transported) for the same period. The shelf-life of wine is often calculated on the basis of the measured values for oxygen permeability. The theoretical shelf-life of wine is 130-450 days for new bags of Met. PET and 30-130 days for worn (transported) bags. The analysis of the wine showed a longer shelf-life than the theoretical calculations. This is because phenolics, which prevent oxidation, are not accounted for in the formula. The formula is therefore probably best suited for white wines. The selection of barrier material for bag-in-box bags (Met. PET, EVOH or Al-lami-nates) does not seem to be critical for the shelf-life of a red table wine with a rather high content of phenolic components if the wine is stored for less than 9 months.     

Effect of packaging oxygen transmission rate on the shelf life of ready-to-heat foods susceptible to postcontamination during refrigerated and illuminated storage

Since more and more pressure is exerted to reduce the use of plastic packaging materials, optimizing the use of food packaging is opportune. The aim of this study was to evaluate the combined effect of packaging materials, spanning a range of oxygen transmission rates (OTR), and retail illumination, on the microbial shelf life and safety of refrigerated ready-to-heat foods. Cooked potato slices were packaged in OPA/PP bags with a high OTR (28.85 ccO₂/m²/d) and OPA-EVOH/PP bags with a low OTR (6.57 ccO₂/m²/d). Cooked composite meals were packaged in tray and foil combinations, also spanning a range of OTR: PP trays (2.09 ccO₂/tray/d) with OPA/PP foils (28.85 ccO₂/m²/d), PP trays with OPA-EVOH/PP (6.57 ccO₂/m²/d) foils, and PET trays (0.07 ccO₂/tray/d) with PET top foil (32.86 ccO₂/m²/d) . The packages were stored in a dark environment, or under fluorescent or LED light. Due to the rapid growth of lactic acid bacteria, the microbial shelf life of both food products was largely unaffected by the type of barrier. Illumination at 1000 lux for 12 hours per day led to temperature differences significantly affecting microbial growth. Based on the results, it could be concluded that re-evaluating packaging material choices for these foods may prove valuable, since the use of high-barrier multilayer packaging materials may be considered as a case of overpackaging.     

纸质食品包装材料中 26 种有机残留物的检测

目的建立纸质食品包装材料中7种指示性多氯联苯、7种增塑剂、7种氯酚类化合物、2种二苯酮类化合物,以及4-辛基酚、2-异丙基硫杂蒽酮和硬脂酸甲酯同时检测的分析方法。方法采用超声提取,气相色谱-串联四极杆质谱多反应监测模式分析。结果 26种有机残留物在0.02~2.0 mg/kg范围内线性关系良好(r20.997),加标浓度在0.1 mg/kg时的平均回收率为88.9%~105.5%,相对标准偏差低于12.2%;方法的检出限为0.000 90~0.0035 mg/kg,定量限为0.0031~0.012 mg/kg。应用该方法对实际样品进行了检测,发现绝大多数样品中均检测出邻苯二甲酸二苯酯类增塑剂(检出含量为0.006~7.02 mg/kg),部分样品还检测出硬脂酸甲酯(检出含量为0.069~0.43 mg/kg)。结论该方法简单、快速、准确、灵敏,可用于纸质食品包装材料及类似基质中多种有机残留物的同时检测。