Active food packaging technologies

Active packaging technologies offer new opportunities for the food industry, in the preservation of foods. Important active packaging systems currently known to date, including oxygen scavengers, carbon dioxide emitters/absorbers, moisture absorbers, ethylene absorbers, ethanol emitters, flavor releasing/absorbing systems, time-temperature indicators, and antimicrobial containing films, are reviewed. The principle of operation of each active system is briefly explained. Recent technological advances in active packaging are discussed, and food related applications are presented. The effects of active packaging systems on food quality and safety are cited.     

Recent advances in biobased and biodegradable polymer nanocomposites,nanoparticles, and natural antioxidants for antibacterial and antioxidant food packaging applications

Inorganic nanoparticles (NPs) and natural antioxidant compounds are an emerging trend in the food industry. Incorporating these substances in biobased and biodegradable matrices as polysaccharides (e.g., starch, cellulose, and chitosan) and proteins has highlighted the potential in active food packaging applications due to more significant antimicrobial, antioxidant, UV blocking, oxygen scavenging, water vapor permeability effects, and low environmental impact. In recent years, the migration of metal NPs and metal oxides in food contact packaging and their toxicological potential have raised concerns about the safety of the nanomaterials. In this review, we provide a comprehensive overview of the main biobased and biodegradable polymer nanocomposites, inorganic NPs, natural antioxidants, and their potential use in active food packaging. The intrinsic properties of NPs and natural antioxidant actives in packaging materials are evaluated to extend shelf-life, safety, and food quality. Toxicological and safety aspects of inorganic NPs are highlighted to understand the current controversy on applying some nanomaterials in food packaging. The synergism of inorganic NPs and plant-derived natural antioxidant actives (e.g., vitamins, polyphenols, and carotenoids) and essential oils (EOs) potentiated the antibacterial and antioxidant properties of biodegradable nanocomposite films. Biodegradable packaging films based on green NPs—this is biosynthesized from plant extracts–showed suitable mechanical and barrier properties and had a lower environmental impact and offered efficient food protection. Furthermore, AgNPs and TiO₂ NPs released metal ions from packaging into contents insufficiently to cause harm to human cells, which could be helpful to understanding critical gaps and provide progress in the packaging field.     

延边地区2011~2015年食品中食源性致病菌的监测

【目的】 了解食品中主要食源性致病菌的污染状况,确定高危食品,为预防和控制食源性疾病提供科学依据。 【方法】 按照《全国食源性致病菌监测工作手册》 的检测技术要求,2011 － 2015 年在延边地区的几个监测点采集食品样品1069份,对沙门氏菌、单核细胞增生李斯特菌（定量）、金黄色葡萄球菌（定量）、铜绿假单胞菌、蜡样芽孢杆菌的污染情况进行监测。 【结果】 1069份样品中,共检出致病菌115株,总检出率为10.76%.熟肉制品、生食动物性水产品、凉拌菜、熟制米面制品、婴幼儿食品、乳及乳制品、速冻米面品、特殊膳食用食品、饮用水、三明治以及流动早餐样品的致病菌检出率分别为17.65%（3/17)、15.79%（3/19)、11.76%(4/34)、34.48%(10/29)、33.80%（24/71）、40.00%(12/30)、6.67%(1/15)、42.86%(6/14)、58.33%（7/12）、10.00%（1/10）和71.43%（10/14）;2011-2015年食源性致病菌检出率分别为0.94% 、1.87% 、6.83% 、0.65%、0.19%。 【结论】 乳及乳制品、特殊膳食用食品、饮用水和流动早餐是延边地区食品的主要污染品种,作为直接入口食品的熟肉制品、凉拌菜、熟制米面制品和婴幼儿食品可能导致较高的食源性疾病风险。     

Developing the NASA food system for long-duration missions

Even though significant development has transformed the space food system over the last 5 decades to attain more appealing dietary fare for low-orbit space crews, the advances do not meet the need for crews that might travel to Mars and beyond. It is estimated that a food system for a long-duration mission must maintain organoleptic acceptability, nutritional efficacy, and safety for a 3- to 5-y period to be viable. In addition, the current mass and subsequent waste of the food system must decrease significantly to accord with the allowable volume and payload limits of the proposed future space vehicles. Failure to provide the appropriate food or to optimize resource utilization introduces the risk that an inadequate food system will hamper mission success and/or threaten crew performance. Investigators for the National Aeronautics and Space Administration (NASA) Advanced Food Technology (AFT) consider identified concerns and work to mitigate the risks to ensure that any new food system is adequate for the mission. Yet, even with carefully planned research, some technological gaps remain. NASA needs research advances to develop food that is nutrient-dense and long-lasting at ambient conditions, partial gravity cooking processes, methods to deliver prescribed nutrients over time, and food packaging that meets the mass, barrier, and processing requirements of NASA. This article provides a brief review of research in each area, details the past AFT research efforts, and describes the remaining gaps that present barriers to achieving a food system for long exploration missions.     

Molecular epidemiology of microorganisms isolated from food workers and enteral feeding of public hospitals

This study aimed to compare strains of Staphylococcus aureus and E. coli isolated from food workers and enteral diet samples obtained from 2 public hospitals (H1/H2) in Goiania, Goias, Brazil, by the means of antibiogram and pulsed field gel electrophoresis (PFGE). In the H1, strains of S. aureus were present in 2 enteral diet samples and in 13 food worker swabs. Strains of E. coli were found in an enteral diet sample from H1 and in 2 enteral diet samples from H2 and in 6 food worker swabs in the H1 and in 12 food worker swabs from H2. According to the antibiogram, the 6 susceptibility profiles (A to F) of 15 S. aureus strains colonizing personnel and enteral feeding did not allow the identification of the probable source of diet contamination. All 20 E. coli strains isolated from the H1 and H2 were grouped in 4 phenotypic profiles (A to D). The phenotypes A (H1) and C (H2) showed the same profile for microorganisms isolated from handlers and diets, suggesting more phenotypic similarity among these samples. PFGE genotyping showed that S. aureus isolates from diets were related to a single strain isolated from a food worker suggesting that in this case the reason for the diet contamination may be a result of food handling. The food worker appears to be the most probable source of E. coli contamination for enteral feeding from H2. This fact emphasizes on the food workers as a risk of bacterial transmission for the diets and that the diet chain production must be controlled. PRACTICAL APPLICATION: The study emphasizes the importance of monitoring the enteral diet microbiological quality and the factors associated to its contamination. The study highlights the use of molecular biology as an instrument to correlate strains to determine the origin of the final product contamination.     

预测微生物学与食品质量安全

预测食品微生物学利用数学模型定量地分析不同环境条件下食品中病原菌和腐败菌的生长和存活，对食品的货架期作出合理的预测。该文简要介绍了预测模型的3个水平及其在预测货架期中的应用，并展望了预测微生物学未来的发展趋势。     

聚集诱导发光型荧光探针在食品中致病菌检测中的应用研究进展

食品安全事件中,食源性致病菌污染是造成群体性中毒、食源性疾病、大规模食品货物召回等的重要原因。食源性致病菌可能在食品加工或流通的任何一个环节进入到食品中,因而在食品生产、加工、包装、运输、销售整个环节中,食源性致病菌的检测都至关重要。近年来,聚集诱导发光(aggregation-induced emission,AIE)型荧光探针由于其高效的荧光效率和光稳定性、分子结构设计多样、检测模式灵活,在食品安全领域致病菌快速检测中展现出了巨大的优势,为食品中致病菌的检测、鉴别、鉴定等提供了一个优异的解决方案。本文从AIE探针的设计、检测效率、检测模式等方面综述了AIE型荧光探针在致病菌检测方面的研究进展,讨论了其在食品安全快速检测中的优势和应用前景,为食品安全快速检测场景下快速检测技术的开发及应用提供参考。     

抗菌涂层包装技术研究综述

抗菌涂层是活性包装技术的一种实现形式,对现代食品的包装和储运有着重要的影响。文中就载体类型、抗菌剂性能和抗菌涂层与其他包装技术相结合3个方面的研究现状作了论述。     

Application of Selected Natural Antimicrobial Formulations for the Control of Food Pathogens in Fresh-Cut Cauliflower

In recent years, research on biopolymer based-coating containing natural antimicrobial agents is developing significantly. The objective of this study was to evaluate the antimicrobial efficiency of six formulations containing pre-selected natural antimicrobial compounds against Listeria monocytogenes, Escherichia coli O 157：H7, Salmonella typhimurium, the total bacteria and total yeasts and molds in cauliflower. Each formulation was subjected to a sensory test in parallel to microbiological analysis and the efficiency during storage at 5 ℃ was evaluated for the two best formulations, based on their ability to eliminate the target microorganisms. Both formulations were able to reduce all pathogens and total flora below detectable levels after 24 h of storage at 5 ℃. Using washing or spraying treatments, the two formulations were able to reduce Listeria to undetectable levels for 3 d. This efficiency was extended to 7 d when the formulations were incorporated into an edible coating. Washing treatment with the two formulations was also able to limit the growth of yeast and molds at levels lower than 2 log, for more than 7 d. The population of E. coli was reduced to below the detection limit during 14 d of storage, after washing treatment with the two formulations. The spraying treatment of cauliflower with the formulations allowed the use of very small amounts of antimicrobials while maintaining a fairly good efficiency, greatly reducing the potential costs of implementing this method in the industry. Future research may focus on development of nanoemulsion of antimicrobial formulations based on the developed antimicrobial formulations in this study to improve the better coating efficiency.     

Recent advances in protein derived bionanocomposites for food packaging applications

Abstract

This review article critically presents a comprehensive overview of the current advances in the research and development of proteins derived bionanocomposites used in food packaging applications. The recent interest in protein-based biomaterials is due to sustainability, renewability, biodegradability and low carbon footprint. The inherent drawbacks of proteins-based materials for food packaging applications are their low mechanical strength, poor thermal, barrier and inferior physicochemical properties. The nanoreinforced bio-based polymers called bionanocomposites provide an opportunity to overcome these issues and have ability to supersede non-biodegradable food packaging plastics produced from petroleum resources. So far, most studied protein derived bionanocomposites suitable for food packaging are soy protein isolates (SPI) and gelatin proteins. Layered silicates are the most promising nanofillers used to increase strength, improve heat resistance and enhance barrier properties of proteins derived materials while montmorillonites (MMT) is the most commonly used silicate nanofiller. This review emphases on the processing strategies used for proteins-based biomaterials, their mechanical and moisture barrier properties for food packaging applications. Different proteins and nanofillers that have been studied to date in proteins derived food packaging applications are also discussed in detail.     

磁性甲壳素/壳聚糖复合材料在食品安全检测中的应用研究进展

重金属污染水体、农兽药残留超标及人工色素的非法添加等引发的食品安全问题屡见不鲜,是人们一直关注的热点问题,因此选择合适的样品前处理方法尤为重要.甲壳素/壳聚糖纳米复合材料具有丰富的官能团、良好的机械性能、耐水性和无毒性等优点,是一种很好的吸附材料.磁性材料具有超顺磁性,能够通过外界磁场的驱动从溶液中迅速分离.将甲壳素/...     

食源性致病菌快速检测技术研究进展

食源性致病菌是影响食品安全的主要问题之一.建立快速的食源性致病菌检测方法对控制农产品和食品从生产、加工、运输、仓储、口岸通关到销售和消费各个环节的生物性风险至关重要.由于传统病原微生物检测耗时长且操作较繁琐,不能及时检测出食品中的病原菌.近年来随着生物技术的快速发展以及对食品安全监测要求的提高,食源性致病菌快速检测方法...     

Culture‐Independent Rapid Detection Methods for Bacterial Pathogens and Toxins in Food Matrices

Rapid detection of bacterial pathogens and toxins in foods is necessary to provide real‐time results to mitigate foodborne illness outbreaks. Cultural enrichment methods, although the most widely used, are time‐consuming and therefore inadequate for rapid pathogen detection from food samples. The development of novel “rapid” detection methods has decreased detection time dramatically. This review presents an overview of detection methods for various foodborne pathogens, including Listeria monocytogenes, Salmonella enterica, and shiga toxin‐producing Escherichia coli, and bacterial toxins in food matrices, with emphasis on those methods which do not require cultural enrichment. Discussed methods include nucleic acid‐, immunological‐, and biosensor‐based techniques. A summary of each type of detection method is given, including referenced methods from the literature. Since these discussed methods do not require cultural enrichment, there is a higher probability of interference from the food matrices. Therefore, the review also discusses the potential interference of food components on detection methods and addresses preprocessing strategies to overcome matrix associated inhibition and to concentrate low quantities of pathogens and toxins in food. Development of rapid and sensitive detection technologies advances and ensures public health safety and security.     

2004—2012年分离自北京口岸进出口食品的沙门菌耐药性分析

目的 了解北京口岸进出口食品中分离沙门菌的耐药状况及耐药谱情况,分析耐药趋势,为制定食品安全监管措施和抗生素的使用提供依据。方法 对65株本实验室分离的沙门菌以及17株参比菌株,共82株沙门菌采用Kindy-Bauer(KB)法检测其对15种抗生素的敏感性,根据美国临床实验室标准化研究所(CLSI)标准进行判断,并对药敏试验结果进行数据分析。结果 65株沙门菌分离株除对头孢吡肟、头孢曲松、阿米卡星、头孢噻肟全部敏感外,对其余11种抗生素均有不同程度的耐药,其中氨苄西林耐药率最高为16.9%(11/65),其次为哌拉西林(13.8%,9/65)、四环素(13.8%,9/65)、卡那霉素(9.2%,6/65)和链霉素(7.7%,5/65)。在所有65株沙门菌分离株中,对1种抗生素耐药的菌株共11株,占16.9%(11/65),对2种抗生素耐药的菌株为1株,占1.5%(1/65),对3种及以上抗生素耐药的多重耐药株为7株,多重耐药率为10.8%(7/65)。结论 北京口岸进出口食品中分离的沙门菌对多种抗生素耐药。     

Prevalence,Antimicrobial Resistance,and Virulence Characteristics of mecA‐Encoding Coagulase‐Negative Staphylococci Isolated from Soft Cheese in Brazil

Coagulase‐negative staphylococci (CoNS), which are generally neglected as foodborne bacteria, are emerging as significant opportunistic pathogens that may be highly resistant to available antimicrobial drugs. In this study, antimicrobial susceptibility patterns, mecA gene occurrence, and virulence‐associated characteristics were evaluated in CoNS isolated from soft cheese in Brazil. A total of 227 bacterial isolates were recovered from 35 cheese samples belonging to 5 batches with 7 different trademarks. The CoNS counts ranged from 10⁶ to 10⁷ CFU/g. High antimicrobial resistance percentages were observed for oxacillin (76.2%), penicillin (78.5%), erythromycin (67.8%), gentamicin (47.2%), clindamycin (35.7%), rifampicin (26.8%), azithromycin (14.7%), tetracycline (14.7%), levofloxacin (14.2%), and sulfamethoxazole‐trimethoprim (11.9%). A low antimicrobial resistance percentage was observed for chloramphenicol (2.3%), and all of the tested bacteria were susceptible to vancomycin and linezolid. In total, a multiple antibiotic resistance (MAR) index of >0.2 was observed for 80.6% of the isolated CoNS. However, the MAR index ranged from 50% to 92.6% when only bacterial cheese isolates belonging to the same trademark were considered. Regarding to the prevalence of CoNS carrying mecA gene, 81.5% of the isolated strains were mecA⁺, and 76.2% of these were phenotypically resistant to oxacillin. Three isolates carried the enterotoxin A gene (sea), 29.5% produced biofilm in a laboratory test, and α‐ or ß‐hemolysis were observed for 3% and 5.2%, respectively. This study highlights the extent of the antimicrobial resistance phenomenon in neglected foodborne microorganisms and the potential public health risks that are related to the consumption of CoNS‐contaminated soft cheese.     

Preparation and properties of polypropylene/clay nanocomposites for food packaging

Polypropylene (PP)/clay nanocomposites based on PP, organic clay (montmorillonite; MMT), and maleated polypropylene (MAPP) were prepared by melt compounding. The mechanical, thermal, morphological, and gas barrier properties of the resulting PP/clay nanocomposites were investigated at varying concentrations of the components for food packaging. The results revealed that the mechanical strengths, including tensile, flexural, and Izod impact strength, were increased for PP/clay nanocomposites compared to neat PP. The thermal properties showed a tendency for the melting and degradation temperatures to increase with the clay concentration. The effect of the compatibilizer was observed using scanning electron microscopy (SEM). The X-ray diffraction pattern of the nanocomposites revealed increased d-spacing of the MMT layers, indicating that the compatibility of neat PP and clay was improved by the addition of MAPP, and the intercalation and partial exfoliation of the layers. The use of clay increased the mobility distance of the gas molecules, leading to the oxygen permeability of neat PP being reduced by 26% to 55%.     

光动力技术研究进展及其在食品工业中的应用前景

食品安全已成为全球关注的热点问题,由各种食源性致病菌引起的食品安全事故屡有发生。因此,开发更加安全高效的杀菌方法,一直以来是食品工业的研发热点之一。光动力技术作为一种新型非热杀菌技术,因其操作简便、杀菌效果优异、安全可靠、绿色环保、成本低等特点而受到多领域学者的广泛关注。本文概述了光动力技术的作用机理,总结了光敏剂及光动力技术应用的研究进展,重点阐述了光动力技术在食品工业中的应用进展和发展前景,可为进一步开发及优化光动力技术应用于食品工业提供借鉴和参考。     

Antimicrobial activity of epsilon-polylysine against Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria monocytogenes in various food extracts

ABSTRACT:  This study compared the antimicrobial effects of ɛ-polylysine (ɛ-PL) against Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria monocytogenes in 6 food extracts and in broth. The food extracts (10% (w/w) in distilled water) evaluated were fat-free and whole fat milk, beef, bologna, rice, and vegetables (50:50 ratio of broccoli and cauliflower). ɛ-PL was tested at 0.005% and 0.02% (w/v) against E. coli O157:H7 and L. monocytogenes , and 0.02% and 0.04% (w/v) against S. Typhimurium . The substrates were inoculated (5 log CFU/mL) and periodically analyzed for surviving populations during storage at 12 °C for 6 d. In general, all 3 pathogens reached 7 to 9 log CFU/mL within 2 d in control substrates (no ɛ-PL). Immediate bactericidal effects ( P < 0.05) following exposure to ɛ-PL were obtained in the rice (all pathogens) and vegetable ( E. coli O157:H7 and S. Typhimurium ) extracts. During storage, antimicrobial effects of ɛ-PL were more pronounced in the food extracts than in the broth medium. The greatest antimicrobial activity for all 3 pathogens was obtained in the rice and vegetable extracts, where counts were reduced ( P < 0.05) to below the detection limit (0.0 log CFU/mL) by one or both ɛ-PL concentrations tested. In the other food extracts (fat-free milk, whole fat milk, beef, and bologna), both ɛ-PL concentrations tested generally resulted in lower ( P < 0.05) pathogen levels at the end of storage compared to initial counts, with better bactericidal effects exerted by the higher of the 2 ɛ-PL concentrations. Additional research is needed to explore the potential antimicrobial effects of ɛ-PL in real food systems.