Quality and safety aspects of reusable plastic food packaging materials: influence of reuse on intrinsic properties

The aim of the project was to develop a comprehensive package of quality assurance criteria for use by the industry and by regulatory authorities to ensure the quality and safety-in-use (sensory, microbiological and chemical safety) of reused plastics for food packaging. The paper describes the investigations into potential adulteration effects by reuse on the intrinsic properties of plastics in more detail. The plastic articles investigated were bottles of polyethylene terephthalate (PET) or polycarbonate (PC) and vending cups of polypropylene (PP). The influence of repeated use on the migration of plastic constituents, degradation products of plastic additives, barrier properties and surface characteristics were investigated. The overall conclusion was that the investigated intrinsic properties of the refillable articles were not significantly influenced by repeated use. Only the hydrophobicity of the refillable PC and PP articles seemed to be influenced by repeated washing. PC bottles washed 15 times were significantly less hydrophobic than unwashed bottles.     

Safety and quality of plastic food packaging materials: validation of a modified chemical inertness test method for refillable poly(ethylene terephthalate) bottles

The increased use of refillable poly(ethylene terephthalate) (PET) bottles as packaging for soft drinks has prompted us to investigate the effect of sorption of artificially introduced chemical contaminants into refillable PET bottles in order to establish a practical and easy-to-apply test procedure to evaluate their chemical inertness. For this evaluation, quick laboratory procedures, which focus on the interaction of PET bottle wall strips in place of actual bottles with a selection of model contaminants representing the myriad of chemicals, are proposed. The first objective of this study was to validate a modified quick chemical inertness test method for refillable bottles by comparing the results of sorption into PET strips with those of tests using actual PET bottles. A further objective was to investigate the stability of refillable PET bottles which were stored under unfavorable conditions, in relation to the chemical inertness behavior of the material. The results indicate the suitability of the modified quick test as it satisfactorily simulates contamination of refillable PET bottles. Moreover, storage of these bottles under unfavorable conditions does not have an adverse effect on the chemical inertness behavior of the plastic material.     

Limonene and Myrcene Sorption into Refillable Polyethylene Terephtalate Bottles, and Washing Effects on Removal of Sorbed Compounds

The sorption of two orange volatile compounds, myrcene and limonene, into refillable polyethylene terephtalate bottles, different types of polyethylene terephtalate strips, and polycarbonate strips, was studied. The bottles were washed with sodium hydroxide solutions and remaining aromas in the plastic were analyzed. Sorption continued during the 12 wks storage, but the major part was sorbed during the first week. Bottles stored at 25°C absorbed considerably more myrcene and limonene than bottles stored at 4°C. A simulated industrial washing procedure removed small amounts of the aromas but 50–80% remained in the packaging material. Polycarbonate absorbed flavors to a much larger extent than did polyethylene terephtalate.     

Sensory characterization of polyester-based bottle material inertness using threshold odour number determination

Refillable polyester bottles, for example polyethylene terephthalate (PET) bottles, are known to interact with chemicals. Aroma compounds from a product can be absorbed by the bottle material, remain after washing and remigrate when the bottle is reused, resulting in off-flavour of the new product. A certified reference material has recently been approved with which the chemical and sensory inertness of refillable bottle materials can be tested. In this study a sensory method aimed at characterizing the sensory inertness properties of the reference bottle material was developed. A use-reuse situation was simulated by storing bottle wall strips in a solution of four odour-active compounds (the loading phase) and, after cleaning, immersing them in water (the remigration phase). The remigration water was analysed with both a sensory method, i.e. determination of the threshold odour number, and chemically using gas chromatography-mass spectrometry (GC-MS). Additionally, another PET and a polyethylene naphthalate (PEN) bottle material were also tested. The sensory threshold determination method could differentiate between the PEN materials and the PET materials. Results from chemical analysis showed that the inertness properties of the PET materials were very similar. The PEN material exhibited significantly superior inertness properties, with only 3-24% of the aroma transfer properties of PET.     

European survey on post-consumer poly(ethylene terephthalate) (PET) materials to determine contamination levels and maximum consumer exposure from food packages made from recycled PET.

Typical contamination and the frequency of misuse of poly(ethylene terephthalate) (PET) bottles are crucial parameters in the risk assessment of post-consumer recycled (PCR) PET intended for bottle-to-bottle recycling for direct food contact applications. Owing to the fact that misuse of PET bottles is a rare event, sustainable knowledge about the average concentration of hazardous compounds in PCR PET is accessible only by the screening of large numbers of samples. In order to establish average levels of contaminants in PET source materials for recycling, PET flakes from commercial washing plants (689 samples), reprocessed pellets (38) and super-clean pellets (217) were collected from 12 European countries between 1997 and 2001. Analysis of these materials by headspace gas chromatography revealed average and maximum levels in PCR PET of 18.6 and 86.0 mg kg-1 for acetaldehyde and 2.9 and 20 mg kg-1 for limonene, respectively. Acetaldehyde and limonene are typical compounds derived from PET itself and from prior PET bottle contents (flavouring components), respectively. Maximum levels in PCR PET of real contaminants such as misuse chemicals like solvents ranged from 1.4 to 2.7 mg kg-1, and statistically were shown to result from 0.03 to 0.04% of recollected PET bottles that had been misused. Based on a principal component analysis of the experimental data, the impact of the recollecting system and the European Union Member State where the post-consumer PET bottles had been collected on the nature and extent of adventitious contaminants was not significant. Under consideration of the cleaning efficiency of super-clean processes as well as migration from the bottle wall into food, it can be concluded that the consumer will be exposed at maximum to levels < 50 ng total misuse chemicals day-1. Therefore, PCR PET materials and articles produced by modern superclean technologies can be considered to be safe in direct food applications in the same way as virgin food-grade PET.     

Identification and quantification of the migration of chemicals from plastic baby bottles used as substitutes for polycarbonate

The results of a study on the analytical identification and quantification of migration of chemicals from plastics baby bottles found in the European Union market made of materials that are now present as substitutes for polycarbonate (PC) are reported. A total of 449 baby bottles with a focus on first age or sets of bottles were purchased from 26 European Union countries, Canada, Switzerland and the USA. From this collection, which contained several duplicates, a total of 277 baby bottles were analysed. The materials included different types of plastic such as PC, polyamide (PA), polyethersulphone (PES), polypropylene (PP), but also silicone, and from the United States a co-polyester marketed under the trade name Tritan?. The bottles were subjected to the conventional migration test for hot fill conditions, i.e. 2?h at 70°C. The simulant used was that specified in European Union legislation (2007/19/EC) for milk, i.e. 50% ethanol. In a first phase 1, migration was conducted since the scope of this investigation was a screening rather than a true compliance testing check. Second and third migrations were performed on selected articles when migrated substances exceeded limits specified in the legislation. In order to verify some materials, a portion of the bottle was cut to run an FT-IR fingerprint to confirm the nature of the polymer. The migration solutions in general showed a low release of substances. Results showed that bottles made of PP and silicones showed a greater number of substances in the migration solutions and in greater quantity. Chemicals from PP included alkanes, which could be found in >65% of the bottles at levels up to 3500?μg?kg?1; and benzene derivatives in 17% of the baby bottles and found at levels up to 113?μg?kg?1. Some substances were found on a regular basis such as plasticisers, esters and antioxidants (e.g. tris(2,4-di-tert-butylphenyl)phosphate, known as Irgafos 168. Some substances found were not included in the Community positive list, which means that those should not be found even in the first migration. Such substances included 2,6-di-isopropylnaphthalene (DIPN), found in 4% of the bottles at levels up to 25?μg?kg?1, 2,4-di-tert-butyl phenol (in 90% of the bottles at levels up 400?μg?kg?1). Moreover, bisphenol A (BPA) was detected and quantified in baby bottles made of PA, but limited to one brand and model specific (but labelled BPA free). Results for baby bottles made of silicone also indicated the presence of components, e.g. potentially coming from inks (benzophenone, diisopropyl naphtahalene - DIPN, which could come for example from the presence of instruction leaflets in the bottles). In the case of silicone, phthalates were also found in relevant concentrations, with levels for DiBP and DBP from the first migration test of 50-150?μg?kg?1 and DEHP at levels 25-50?μg?kg?1.     

聚酯瓶包装新猷——内壁表面无定形碳涂层处理

<正> 在塑料包装工业中,PET的透过性一直限制了瓶装饮料的保质期,寻找改进包装阻隔性的方法是业者长期的研究课题,对它在啤酒领域的应用更是近年间的一项大挑战。总结过去的试验结果,已研究出从使用PEN作为原材料到以EVOH为阻隔基料的多层材料,到采用在瓶外壁喷涂阻隔性涂料等各种方法。然而,与玻璃瓶和金属罐相比,这些方法比较昂贵,产品的保质期也相当有限。     

Identification of chemicals, possibly originating from misuse of refillable PET bottles, responsible for consumer complaints about off-odours in water and soft drinks

Mineral water and soft drinks with a perceptible off-odour were analysed to identify contaminants originating from previous misuse of the refillable polyethylene terephthalate (PET) bottle. Consumers detected the off-odour after opening the bottle and duly returned it with the remaining content to the producers. The contaminants in question had thus been undetected by the in-line detection devices (so-called 'sniffers') that are supposed to reject misused bottles. GC-MS analysis was carried out on the headspace of 31 returned products and their corresponding reference products, and chromatograms were compared to find the possible off-odour compounds. Substances believed to be responsible for the organoleptic change were 2-methoxynaphthalene (10 bottles), dimethyl disulfide (4), anethole (3), petroleum products (4), ethanol with isoamyl alcohol (1) and a series of ethers (1). The mouldy/musty odour (5 bottles) was caused by trichloroanisole in one instance. In some cases, the origins of the off-odours are believed to be previous consumer misuse of food products (liquorice-flavoured alcohol, home-made alcohol containing fusel oil) or non-food products (cleaning products, petroleum products, oral moist snuff and others). The results also apply to 1.5-litre recyclable PET bottles, since the nature and extent of consumer misuse can be expected to be similar for the two bottle types.     

洗衣机净洗能力检测用可可污染布的制备及性能评价

可可污染布作为国际标准IEC 60456中检测洗衣机洗涤性能的标准污染布之一,目前国内研究较少。探讨了可可污染布的制备方法,分析了体系黏度、粒径对污液稳定性的影响,并对污染布的色度、着色均匀性和净洗性能进行了研究。结果表明:自制可可污染布的色度值与符合国际标准的可可污染布相近,两者洗净性能相当。自制可可污染布具有潜在应用前景。     

Identification and quantification of the migration of chemicals from plastic baby bottles used as substitutes for polycarbonate

The results of a study on the analytical identification and quantification of migration of chemicals from plastics baby bottles found in the European Union market made of materials that are now present as substitutes for polycarbonate (PC) are reported. A total of 449 baby bottles with a focus on first age or sets of bottles were purchased from 26 European Union countries, Canada, Switzerland and the USA. From this collection, which contained several duplicates, a total of 277 baby bottles were analysed. The materials included different types of plastic such as PC, polyamide (PA), polyethersulphone (PES), polypropylene (PP), but also silicone, and from the United States a co-polyester marketed under the trade name Tritan?. The bottles were subjected to the conventional migration test for hot fill conditions, i.e. 2?h at 70°C. The simulant used was that specified in European Union legislation (2007/19/EC) for milk, i.e. 50% ethanol. In a first phase 1, migration was conducted since the scope of this investigation was a screening rather than a true compliance testing check. Second and third migrations were performed on selected articles when migrated substances exceeded limits specified in the legislation. In order to verify some materials, a portion of the bottle was cut to run an FT-IR fingerprint to confirm the nature of the polymer. The migration solutions in general showed a low release of substances. Results showed that bottles made of PP and silicones showed a greater number of substances in the migration solutions and in greater quantity. Chemicals from PP included alkanes, which could be found in >65% of the bottles at levels up to 3500?µg?kg^?1; and benzene derivatives in 17% of the baby bottles and found at levels up to 113?µg?kg^?1. Some substances were found on a regular basis such as plasticisers, esters and antioxidants (e.g. tris(2,4-di-tert-butylphenyl)phosphate, known as Irgafos 168. Some substances found were not included in the Community positive list, which means that those should not be found even in the first migration. Such substances included 2,6-di-isopropylnaphthalene (DIPN), found in 4% of the bottles at levels up to 25?µg?kg^?1, 2,4-di-tert-butyl phenol (in 90% of the bottles at levels up 400?µg?kg^?1). Moreover, bisphenol A (BPA) was detected and quantified in baby bottles made of PA, but limited to one brand and model specific (but labelled BPA free). Results for baby bottles made of silicone also indicated the presence of components, e.g. potentially coming from inks (benzophenone, diisopropyl naphtahalene – DIPN, which could come for example from the presence of instruction leaflets in the bottles). In the case of silicone, phthalates were also found in relevant concentrations, with levels for DiBP and DBP from the first migration test of 50–150?µg?kg^?1 and DEHP at levels 25–50?µg?kg^?1.     

PET瓶在热灌装饮料中的应用

通过PET的分子结构、物理／化学特性来说明影响PET瓶品质的物理、化学因素；通过PET瓶的生产工艺流程及热灌装PET的吹瓶方法／过程、及影响因素来说明PET瓶品质问题的产生原因及其解决方法；通过PET瓶在热灌装线的使用过程来说明影响PET热灌装饮料包装品质的因素及其解决方法；从而为PET瓶在热灌装线的使用提供了较有借鉴意义的一手资料。     

PET瓶在热灌装饮料中的应用

通过PET的分子结构、物理/化学特性来说明影响PET瓶品质的物理、化学因素;通过PET瓶的生产工艺流程及热灌装PET的吹瓶方法/过程、及影响因素来说明PET瓶品质问题的产生原因及其解决方法;通过PET瓶在热灌装线的使用过程来说明影响PET热灌装饮料包装品质的因素及其解决方法;从而为PET瓶在热灌装线的使用提供了较有借鉴意义的一手资料。     

Enhancing and accelerating flavour formation by salt-tolerant yeasts in Japanese soy-sauce processes

In soy-sauce processes salt-tolerant yeasts are very important for the flavour formation. This flavour formation is, however, slow and poorly understood. In the last decades, a concerted research effort has increased the understanding and resulted in the derivation of mutants with an enhanced flavour formation. In addition, a new process using immobilized salt-tolerant yeasts has been developed and shown to be very effective for accelerating the flavour formation. From this study, it was, however, concluded that immobilizing the salt-tolerant yeasts gives only small productivity benefits to this new process. For increasing the productivity, the continuous microfiltration membrane reactor seems to be a good alternative.     

Mycotoxins in dairy products

Certain fungi produce chemical substances that cause toxic symptoms when food containing them is ingested by man or animals. These compounds are referred to as mycotoxins. Mycotoxins may contaminate dairy products by moulds growing on them, or by the carry-over of mycotoxins occurring in animal feedstuffs ingested by dairy cattle. An example of the first mentioned category is sterigmatocystin, a carcinogenic mycotoxin sometimes occurring on hard cheese. An example of the second category is aflatoxin M₁, a compound strongly suspected to be carcinogenic, which often occurs in milk. Due to the fact that processing of milk does not decrease the aflatoxin M₁ content, aflatoxin M₁ occurs in various dairy products. Sensitive methods of analysis for the determination of mycotoxins in dairy products have been developed in the last 10 years, most of them are based on TLC- or HPLC-separation procedures, followed by fluorimetric measurement.The most fundamental way to tackle the problem of mycotoxin contamination of dairy products is to prevent fungal growth on the dairy products or, in the case of carry-over of mycotoxins, in the crop before, during and after harvest. If measures to prevent fungal growth and mycotoxins production are not taken or fail, one can sometimes resort to physical or chemical methods to eliminate mycotoxins.     

塑料包装材料在啤酒工业中的应用

高阻隔型啤酒包装材料具有玻璃啤酒瓶的性能，而且还有轻便、安全、贮运方便，成本低，可回收利用等优点，可代替玻璃啤酒瓶，成为21世纪啤酒行业的主导包装材料。目前，澳大利亚、德国、意大利、美国、荷兰、法国、日本、中国等许多国家已生产和使用塑料啤酒瓶。高阻隔性、多功能保鲜性、无茵性包装材料、纳米复合包装材料将成为21世纪啤酒包装材料研究和应用的重点。     

Influence of flavour absorption by food-packaging materials (low-density polyethylene, polycarbonate and polyethylene terephthalate) on taste perception of a model solution and orange juice

The influence of flavour absorption by low-density polyethylene (LDPE), polycarbonate (PC) and polyethylene terephthalate (PET) on taste perception of a model solution containing seven flavour compounds and orange juice in glass bottles was studied with and without pieces of the respective plastic films after dark storage at 20°C. Owing to absorption, the amount of flavour compounds in the model solution exposed to LDPE decreased substantially. From the model flavour solution valencene was almost completely absorbed by LDPE, followed to a lesser extent by decanal, hexyl acetate, octanal and nonanone. Less flavour compounds were absorbed from the model solution by PC and PET. In contrast to LDPE, valencene was absorbed in the lowest amounts and decanal in the highest. Limonene was readily absorbed from orange juice by LDPE, while myrcene, valencene, pinene and decanal were absorbed in smaller quantities. Only three flavour compounds were absorbed from orange juice by PC and PET in very small amounts: limonene, myrcene and decanal. Although the flavour content between controls and polymer-treated samples differed substantially, the loss of flavour compounds due to absorption by LDPE, PC and PET did not influence taste perception of a model solution and orange juice significantly up to 29 days of dark storage at 20°C as determined by triangular taste panel tests.     

Comparing effects of washing,thermal treatments and gamma irradiation on quality of spieces

Selected five spices were treated with simple natural methods as washing with pure tap water then drying at room temperature, thermal treatment at 70 °C/15 minutes besides irradiation with 5.0 and 10 kGy. The evaluation of the used treatments efficiency depends on microbiological and chemical studies. The results show that untreated samples were highly contaminated with pathogenic and toxigenic microbes. Gamma irradiation was effective in decontamination especially 10 kGy but caused losses in major components of flavour as anethol, mechavicul, anise-aldehyde in anise, β-pinen and cineol in black pepper. Also, irradiation induced the changes of monoterpene hydrocarbons to alcohol terpens in essential oils of black pepper. Thermal treatment reduced the microbial count and pathogenic microbes to the same safe range as an irradiation dose of 5 kGy. Thermal techniques improved the flavour, as anisealdehyde in fennel, anethol in anise and B-pinen in black pepper. Washing of the spices removed slightly the microbes but revealed no changes in flavour except the anise flavour which increased markedly. Finally, thermal and washing treatments could be recommended as simple natural techniques to produce spices with good flavour and in safe range for hygienic quality comparing with sterilized dose 10 kGy.     

BOPP瓶与PET瓶在热灌装果汁及饮料应用上之比较

以白柚果汁为例，分别热灌装于BOPP（biaxial oriented polypropyle与PET（polyethylene terehthalate)瓶内，藉分析贮藏35d于4℃、25℃及37℃之温度下样品之物理化学性质，探讨两种包材对于热罐装饮料品质影响。     

Non-targeted multi-component analytical surveillance of plastic food contact materials: Identification of substances not included in EU positive lists and their risk assessment

A procedure used by the Norwegian Food Safety Authority for surveillance of contaminants from plastic food contact materials (polyolefin drinking bottles, water boilers, polyamide cooking utensils and plastic multi-layer materials) is described. It is based on gas chromatographic-mass spectrometric (GC/MS) analysis of food simulants exposed to plastic materials. Most migrants were substances not-intentionally added to the plastic (degradation products, impurities) or originated from non-plastic components, such as printing inks, adhesives, not-listed additives, solvents and coatings. Hence, the majority of the identified migrants were regulated by the general statements in the EU Framework Regulation, which neither specify limits nor requirements regarding risk assessment, rather than by specific migration controls. Risk assessment has been carried out for selected non-authorized substances. The analysis and the management of these substances and materials with respect to safety represents a challenge to the food authorities.     

浸冲式洗瓶机进瓶装置的比较研究

浸冲式洗瓶机广泛应用于液体灌装生产线中,主要用来对玻璃瓶进行清洗.其组成结构比较复杂,进瓶装置是一个重要的组成部分.通过对几种进瓶方案的分析探讨,总结出进瓶装置的设计关键,对洗瓶机进瓶装置的系列化设计、技术改造提供了参考.