抗菌包装膜对异硫氰酸烯丙酯的释放规律研究

缓释型抗菌包装是具有缓慢释放抗菌成分性能的一种活性包装。利用β-环糊精包埋异硫氰酸烯丙酯制备抗菌复合物,并将复合物与聚乳酸、聚乙二醇共混挤压吹塑制备了抗菌包装膜,研究了抗菌包装材料中异硫氰酸烯丙酯在不同环境条件下的释放规律和对常见食品微生物的抑制作用。结果表明,挥发性抗菌剂经过环糊精包埋,其耐热性得到明显提高,热加工损失率从98.77%降低到75.56%;抗菌包装控制抗菌剂释放的速率随着环境湿度和温度的升高而增大;同时,此抗菌包装对常见食品微生物具有较强的抑制作用,其中对酵母、霉菌的抑制作用强于细菌。      

Short-term toxicity study of allyl isothiocyanate in rats

Allyl isothiocyanate (AITC) was given in doses of 0, 10, 20, or 40 mg/kg (5 days/week) by oral intubation to male rats for up to 6 weeks. The highest dosage level caused a decrease in body weight, thymus weight, blood glucose and serum globulin levels. Haematological examination revealed an increased percentage of neutrophils and a decreased percentage of lymphocytes after treatment for 2 weeks. Increased liver and adrenal weights were found in all test groups. Renal dysfunction was indicated by increased urinary aspartate amino-transferase activity, reduced urine volume and changes in the specific gravity of the urine. Histopathological changes were observed in the kidneys of animals at dosages of 20 and 40 mg/kg and in the livers of animals at the highest dosage level.     

Effect of free-SH containing compounds on allyl isothiocyanate antimicrobial activity against Escherichia coli O157:H7

ABSTRACT:  Escherichia coli O157:H7 contamination is a significant meat safety issue in many countries. Allyl isothiocyanate (AIT) is a natural compound found to limit the survival of E. coli O157:H7 and other pathogens in meat and meat products. In the present study, it was found that glutathione and cysteine naturally present in meat can interfere with AIT antimicrobial activity. Spectroscopy, HPLC, and LC-MS were used to confirm that glutathione was able to react with AIT and formed a conjugate with no or low bactericidal activity against the tested organisms. The same reaction also occurred at pH values of 4.9 and 5.8 at 25 and 4 °C, respectively, which broadly represent storage conditions in raw beef (pH 5.8) and during fermented sausage (pH 4.9) manufacture. Reactions observed help to explain reduction in antimicrobial potency of AIT in food (meat) systems.     

浅述国外食品包装安全体系

欧美发达国家特别是美国和法国十分重视包装安全工作，也是世界上包装安全法规，安全体系最完善的国家。无论是军品弹药包装，危险化学品包装，还是食品安全包装，都有系统的安全法规，完善的管理体系，以及安全行动计划。[编者按]     

Development of a molecular detection and differentiation system for ochratoxin A producing Penicillium species and its application to analyse the occurrence of Penicillium nordicum in cured meats

A PCR method for differentiation and detection of the two known ochratoxin A producing Penicillium species, Penicillium verrucosum and Penicillium nordicum has been developed. It is based upon two genes of the ochratoxin A biosynthetic pathway, namely the ochratoxin A polyketide synthase gene (otapksPN) and a non-ribosomal peptide syntethase gene (otanpsPN) from P. nordicum. Both ochratoxin A producing Penicillia differ characteristically in the PCR result, making a taxonomic differentiation possible. P. verrucosum gives consistently only a positive reaction with the primers for the otanpsPN gene, whereas P. nordicum is positive for both genes. The PCR reaction is negative with all of other food related fungal species tested. This PCR system has been used to analyse 62 Penicillium strains isolated from cured meat products or ripening rooms, the natural habitat of P. nordicum. Among the 62 analysed strains 11 (18%) were positive with all specific PCR reactions. All 11 strains were able to produce ochratoxin A. In a RAPD analysis performed in parallel all 11 strains showed a pattern characteristic of P. nordicum, indicating the congruence of all data. None of the other strains isolated from cured meat produced ochratoxin A; most of them (30 out of 62) had a RAPD pattern characteristic for Penicillium nalgiovense. Interestingly some of the P. nalgiovense strains showed weak PCR product bands with varying length after electrophoresis. This was true for both primer pairs. None of these P. nalgiovense strains however produced detectable amounts of ochratoxin A. A more detailed analysis revealed that P. nalgiovense carries similar but non-transcribed sequences to the ochratoxin A biosynthetic genes of P. nordicum.     

Radio frequency reheating behavior in a heterogeneous food: A case study of pizza

Radio frequency (RF) energy could rapidly raise the material bulk temperature with deep power penetration and high energy efficiency. Although many studies on RF treatments have been carried out on different agricultural commodities or food, application of RF energy for studying heating behavior of heterogeneous food matrix is limited. Pizza is typically a heterogeneous food model with a base, cheese matrix and added toppings, and has been rarely evaluated for RF reheating. This study was aimed at using computer simulation for evaluating the RF reheating uniformity of a typical model pizza after baking based on measured thermal and dielectric properties (DPs) of its components (pizza base, cheese, salami and onion). The validation experiments were carried out up to a maximum reheating temperature of 85 °C in a 6 kW, 27.12 MHz RF system. The results showed that both dielectric constant and loss factor of pizza components increased with temperature, and at elevated temperatures, DP values for salami were the highest cheese, onion and pizza base. Both computer simulation and experiment provided similar temperature-time histories (with the maximum RMSE of 0.034 °C) in pizza base, cheese, salami and onion after RF reheating for 7.33 min. The fast RF reheating rate was observed in cooked salami both from the temperature-time history and predicted temperature distribution due to closed dielectric loss to constant value. The high sample temperature resulted in low moisture content. The RF heating uniformity could be improved by moving or rotating pizza and specially locating components in the further studies.     

中国食品包装机械发展综述

我国食品包装机械发展形势良好 近5年来食品和包装机械行业每年以11%～12%的平均增长速度发展,高于同期国民经济增长速度.产品水平上了新台阶,开始出现规模化、成套化、自动化的趋势,传动复杂、技术含量高的设备开始出现.在出口的机械品种中以食品(乳品、糕点、肉类、水果)加工机、烤箱、封装、贴标签机、纸塑铝复合罐生产设备等机械出口较多,食品机械如制糖、酿酒、饮料、液体食品灌装机等设备已开始成套出口.     

Antimicrobial activity of cyclodextrin entrapped allyl isothiocyanate in a model system and packaged fresh-cut onions

The aim of this work was to determine the antimicrobial effect of allyl isothiocyanate (AIT) entrapped in alpha and beta cyclodextrin inclusion complexes (ICs). In model experiments, AIT formulations were applied to filter paper discs fixed inside the lid of Petri dishes, where the agar surface was inoculated with the target organism (Penicillium expansum, Escherichia coli or Listeria monocytogenes). Solid phase microextraction coupled with gas chromatography was used to determine static headspace concentrations of AIT formulations. The antimicrobial effect of beta IC was determined during aerobic storage of packaged fresh-cut onions at 5 °C for 20 days. AIT entrapped in beta IC exhibited a significantly (p < 0.05) better antimicrobial effect compared to unentrapped AIT. AIT vapour concentrations in the static system were highest for unentrapped AIT followed by beta IC and alpha IC. Application of beta IC (200 μl/l) to packaged fresh-cut onions effectively decreased numbers of L. monocytogenes, which were also decreased at slower rates to undetectable levels on untreated cut onion. After 10 days, total aerobic counts were ca. 4 log CFU/g lower on onions treated with beta IC (100 and 200 μl/l) compared to untreated controls. This work demonstrates the utility of beta IC as an antimicrobial treatment with potential applications in packaged fresh-cut vegetable products.     

Development of cellulose-based bactericidal nanocomposites containing silver nanoparticles and their use as active food packaging

The use of nanomaterials, including metallic as active fillers in polymeric nanocomposites for food packaging has been extensively investigated. Silver nanoparticles (AgNPs), in particular, have been exploited for technological applications as bactericidal agents. In this paper, AgNPs were incorporated into a hydroxypropyl methylcellulose (HPMC) matrix for applications as food packaging materials. The average sizes of the silver nanoparticles were 41 nm and 100 nm, respectively. Mechanical analyses and water vapor barrier properties of the HPMC/AgNPs nanocomposites were analysed. The best results were observed for films containing smaller (41 nm) AgNPs. The antibacterial properties of HPMC/AgNPs thin films were evaluated based on the diameter of inhibition zone in a disk diffusion test against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). The disk diffusion studies revealed a greater bactericidal effectiveness for nanocomposites films containing 41 nm Ag nanoparticles.     

Quality of chilled ready-to-bake pizza stored in air and under modified atmospheres: Microbiological and sensory attributes

Modified atmosphere packaging (MAP) studies on microbiological and sensory analysis were conducted to extend the shelf life of ready-to-bake pizza stored at 7±1°C. The gas combinations used were: atm1: air (control), atm2: CO₂ (100%), atm3: N₂ (100%), atm4: 50% CO₂/50% N₂. Total plate count (TPC), yeasts/molds (Y/M), coliforms, lactic acid bacteria (LAB), psychrotrophs, and anaerobic spore formers were estimated at time intervals of 0, 5, 10, 15, and 20 days. TPC and LAB of pizza samples (atm1) reached 7.10 and 8.14 log CFU/g after 10 days of storage, respectively. Coliforms, psychrotrophs, and Y/M were significantly higher (p<0.05) for pizza samples stored in atm1 than other storage conditions of MAP. Finally, counts of anaerobic spore formers were low (<3 log CFU/g) irrespective of the packaging conditions throughout the entire storage period. It was concluded that among the 4 atmospheres examined, atm2 (100% CO₂) was the best, followed by atm4>atm3>atm1 respectively, in descending order. MAP conditions under this study may extend shelf life of pizza to considerable amount of time.     

The role of smart packaging system in food supply chain

Food supply chain is a rapidly growing integrated sector and covers all the aspects from farm to fork, including manufacturing, packaging, distribution, storing, as well as further processing or cooking for consumption. Along this chain, smart packaging could impact the quality, safety, and sustainability of food. Packaging systems have evolved to be smarter with integration of emerging electronics and wireless communication and cloud data solutions. Although there are many factors causing the loss and waste issues for foods throughout the whole supply chain of food and there have been several articles showing the recent advances and breakthroughs in developing smart packaging systems, this review integrates these conceptual frameworks and technological applications and focuses on how innovative smart packaging solutions are beneficial to the overall quality and safety of food supply by enhancing product traceability and reducing the amount of food loss and waste. We start by introducing the concept of the management for the integrated food supply chain, which is critical in tactical and operational components that can enhance product traceability within the entire chain. Then we highlight the impact of smart packaging in reducing food loss and waste. We summarize the basic information of the common printing techniques for smart packaging system (sensor and indicator). Then, we discuss the potential challenges in the manufacturing and deployment of smart packaging systems, as well as their cost-related drawbacks and further steps in food supply chain.     

Development of an active food packaging system with antioxidant properties based on green tea extract

A formula including green tea extract (GTE) was developed as an active food packaging material. This formula was moulded to obtain an independent component/device with antioxidant properties that could be easily coupled to industrial degassing valves for food packaging in special cases. GTE components (i.e., gallic acid, catechins and caffeine) were identified and quantified by HPLC-UV and UPLC-MS and migration/diffusion studies were carried out. Antioxidant properties of the formula alone and formula-valve were measured with static and dynamic methods. The results showed that the antioxidant capacity (scavenging of free radicals) of the new GTE formula was 40% higher than the non-active system (blank). This antioxidant activity increased in parallel with the GTE concentration. The functional properties of the industrial target valve (e.g., flexibility) were studied for different mixtures of GTE, and good results were found with 17% (w/w) of GTE. This new active formula can be an important addition for active packaging applications in the food packaging industry, with oxidative species-scavenging capacity, thus improving the safety and quality for the consumer and extending the shelf-life of the packaged food.     

Development of anti-insect food packaging film containing a polyvinyl alcohol and cinnamon oil emulsion at a pilot plant scale

Anti-insect packaging films containing cinnamon oil (CO) encapsulated by polyvinyl alcohol (PVA) for repelling Plodia interpunctella (Hübner) larvae were manufactured using pilot plant scale instruments. The microcapsule emulsion of CO and PVA was printed onto polypropylene (PP) film as an ink mixture using the gravure printing method. The printed PP film was then laminated with a low-density polyethylene (LDPE) film to protect the printed side. Four types of multilayer films were produced: control film, 2% CO film, encapsulated 1% CO film, and encapsulated 2% CO film. When mechanical properties were assessed, tensile strength and elongation-at-break were not significantly different among films, whereas the Young's modulus values were different between the control film and the three types of CO-containing films. In a repellent test, 2% CO film repelled P. interpunctella larvae most effectively. For sensory evaluation, which was performed using milk chocolate, caramel soft candy, and cookies packaged with the produced films, the produced films did not affect the sensory characteristics. Therefore, the films printed with emulsions of CO and PVA could be applied in the food industry to help protect foods from infestation by P. interpunctella.     

Inactivation of Escherichia coli O157:H7 in packaged ground beef by allyl isothiocyanate

Commercial allyl isothiocyanate (AIT) was examined for its ability to reduce numbers of Escherichia coli O157:H7 inoculated in fresh ground beef packaged under nitrogen and stored refrigerated or frozen. A five-strain cocktail of E. coli O157:H7 containing 3 or 6 log10 cfu/g was inoculated into 100 g ground beef and formed into 10x1-cm patties. A 10-cm diameter filter paper disk treated with AIT suspended in sterile corn oil was placed on top of a single patty. One patty and paper disk were placed in a bag of Nylon/EVOH/PE with O2 permeability of 2.3 cm3 m(-2) 24 h atm at 23 degrees C. The bags were back-flushed with 100% nitrogen, heat-sealed and stored at 10, 4 and -18 degrees C for 8, 21 or 35 days, respectively. During storage, the AIT levels in the package headspaces were determined by gas liquid chromatography, and mesophilic bacteria and E. coli O157:H7 were counted. The mesophilic aerobic bacteria in ground beef patties were largely unaffected by the addition of AIT. At an initial population of 3 log10 cfu/g, E. coli O157:H7 was reduced by AIT to undetectable levels after 18 days at 4 degrees C or 10 days at -18 degrees C. In samples inoculated with 6 log10 cfu/g, a >3 log10 reduction of E. coli O157:H7 was observed after 21 days at 4 degrees C, while a 1 log10 reduction was observed after 8 and 35 days at 10 and -18 degrees C, respectively. The final AIT concentrations in the headspaces after storage at 10, 4, and -18 degrees C were 444, 456, and 112 microg/ml at 8, 21, and 35 days, respectively. Results showed that AIT can substantially reduce numbers of E. coli O157:H7 in fresh ground beef during refrigerated or frozen storage.     

Development of PLA films containing oregano essential oil (Origanum vulgare L. virens) intended for use in food packaging

Consumers’ concerns about the environment and health have led to the development of new food packaging materials avoiding petroleum-based matrices and synthetic additives. The present study has developed polylactic acid (PLA) films containing different concentrations of essential oil from Origanum vulgare L. virens (OEO). The effectiveness of this new active packaging was checked for use in ready-to-eat salads. A plasticising effect was observed when OEO was incorporated in PLA films. The rest of the mechanical and physical properties of developed films did not show much change when OEO was included in the film. An antioxidant effect was recorded only for films containing the highest percentages of the active agent (5% and 10%). In addition, films exhibited in vitro antibacterial activity against Staphylococcus aureus, Yersinia enterocolitica, Listeria monocytogenes, Enterococcus faecalis and Staphylococcus carnosus. Moreover, in ready-to-eat salads, antimicrobial activity was only observed against yeast and moulds, where 5% and 10% of OEO was the most effective.     

食品金属包装材料中化学物的迁移研究进展

基于目前关于食品用金属包装材料中有毒有害物质迁移研究还基本空白的现状,本文介绍了金属包装材料中的潜在迁移情况,并着重介绍了重金属、双酚类物质和三聚氰胺等潜在迁移物及其研究现状,探讨了金属包装材料中化学物迁移研究的一般过程,为后期金属罐内有害物质的迁移研究和食品包装行业的危害分析和关键控制点(HACCP,Hazard Analysis and Critical Control Point)管理提供依据。