Factors affecting radiation D-values (D₁₀) of an Escherichia coli cocktail and Salmonella Typhimurium LT2 inoculated in fresh produce

Abstract: This study evaluated the effect of produce type, resuspension medium, dose uniformity ratio (DUR), and sample preparation conditions (tissue exposure, MAP, anoxia) on the D₁₀‐value of an Escherichia coli cocktail (BAA‐1427, BAA‐1428, and BAA‐1430) and Salmonella Typhimurium LT2 inoculated on the surfaces of tomato, cantaloupe, romaine lettuce, and baby spinach. Produce at room temperature were irradiated using a 1.35 MeV Van de Graaf electron beam accelerator at 0.2 to 0.9 kGy. The D₁₀‐values for E. coli and Salmonella were 0.20 ± 0.01 kGy and 0.14 ± 0.01 kGy, respectively. Bacterial inactivation was not affected by produce type as long as the samples were irradiated in unsealed bags, the bacteria were suspended in broth, and the sample tissue was exposed. Sample location in front of the e‐beam source during exposure is crucial. A 20% increase in DUR yielded a 53% change in the D_10‐values. Variations in sample preparation, microbiological methods and irradiation set‐up, result in variable D₁₀‐values for different microorganisms on fresh produce. Practical Applications: Most irradiation studies disregard the effect of sample handling and processing parameters on the determination of the D₁₀‐value of different microorganisms in fresh and fresh‐cut produce. This study shows the importance of exposure of sample, resuspension medium, available oxygen, and dose uniformity ratio. D₁₀‐values can differ by 35% to 53% based on these factors, leading to considerable under‐ or over‐estimation of the irradiation treatment. Results from this study will help to lay firm groundwork for future studies on D₁₀‐values determination for different pathogens on fruits and vegetables.     

果蔬产业中绿色加工技术的研究与应用

随着社会的持续发展和技术的不断创新,我国果蔬产业经历了一个快速发展时期。诸多新技术、新材料和新理念被应用到果蔬加工中。绿色食品正是为了满足消费者日益增长的食品需求而提出的理念,应用绿色加工技术是未来果蔬加工的必然趋势。本文提出了果蔬绿色加工技术的定义,阐述了绿色加工技术在果蔬产业中的研究和应用现状及存在的问题,并就果蔬绿色加工技术前景进行了展望,以期引起果蔬加工产业各方的重视和共鸣,推动果蔬绿色加工技术的持续研究和应用。     

种子抑菌研究进展

种子作为植物遗传资源的有效保存体,对延续物种起着重要作用,也是重要的种质创新原料.因其具有一定的抑菌作用,在医用及食用领域被广泛研究与应用.该文论述银杏、苦参、薏仁、萝卜籽等多类植物种子中的抑菌蛋白、多酚类物质、原花青素、生物碱类等活性物质对大肠杆菌、金黄色葡萄球菌、黑曲霉、青霉、毛霉等细菌或真菌的抑制作用,并且综述其...     

Appetite,hunger, and satiety in the elderly

Food intake declines with age and the elderly frequently report a decrease in appetite. Social and physical factors as well as decreased energy expenditure may be part of the explanation for the decreased food intake; however, it is possible that changes in hunger mechanisms are also involved, but more studies similar to those conducted on thirst are needed. The consumption of a varied diet depends in part on sensory‐specific satiety, that is, the decrease in the pleasantness of a food as it is consumed. We have shown that sensory‐specific satiety changes with age such that it was absent in individuals over the age of 65 and this could be part of the explanation of why the elderly consume more monotonous diets. Additional basic studies on how aging affects the controls of food intake will suggest ways to improve the nutritional status of the elderly.     

冷链物流体系中果蔬产品质量安全问题与对策

简要介绍了水果、蔬菜农药残留和植物生长激素残留的问题与现状,总结了冷链在果蔬产品的收购、贮运、销售等环节的作用及存在的问题. 为保障冷链物流体系中果蔬产品的质量与安全性,提出了包括加强硬件设施、提升软件技术、引入第三方物流企业、发展可追溯体系等在内的提升我国食品冷链运输能力的建议.     

基于新资源挖掘的果蔬健康效应与绿色制造研究进展

果蔬富含维生素、矿物质、多糖、多酚、萜类以及生物碱等多种功能成分,具有多种健康功效,对维持人体健康至关重要。长期缺乏果蔬营养会引发“隐性饥饿”,导致机体营养感知失调和代谢紊乱,进而诱发多种慢性疾病。我国是全球最大的果蔬种植和生产国,深入挖掘果蔬新资源对机体生理功能的影响及作用机制,是促进其高效、高值化利用,践行“大食物观”,应对“隐性饥饿”,满足居民营养健康需求的重要举措。在可持续发展与“双碳目标”战略背景下,如何确保人们获得所需的果蔬营养,同时减轻生产对环境的负担已成为刻不容缓的议题。本文围绕“功能成分-绿色制造-提质增效”,综述果蔬资源中功能成分挖掘、健康调控新功能、作用机制及其绿色制造的关键共性技术等,为促进果蔬资源绿色低碳、高效高值和综合循环利用以及产业高质量发展提供重要参考。     

平行板电极法检测食品电学特性研究进展

平行板电极技术被广泛应用于农产品原料理化指标的检测中,因精度高、方便快速且具有无损性的特点而见于诸多研究报道。可对食品原料的电学参数如阻抗Z、等效电容C、导纳Y、品质因素Q、相位角θ、介电常数ε等进行检测,用于其理化性质、生理状态、品质的评估。对食品物料电学参数的影响因素较多,有环境温度、环境压力和频率因素,还包括食品本身的水分、盐分、成熟度、新鲜度和形态体积等内部因素。文章阐述平行板技术的测试原理,并从果蔬类原料的成熟度无损检测、液态类食品的品质分析等方面对该技术的应用情况进行综述,以期为利用平行板技术检测食品材料的相关研究提供参考。     

枕式果蔬食品包装机的设计与试验

随着生活水平的提高,人们对果蔬的需求越来越大.对果蔬食品进行包装不仅外形精美,而且易于保鲜,目前的果蔬食品主要依靠人工包装,效率低.根据果蔬包装的工艺流程,设计了一种枕式果蔬食品包装机,能够适用于不同形状大小的果蔬食品包装.重点对送膜机构、纵封机构和横封机构进行了设计.制作样机,试验得到:包装机的包装速度为151包/m...     

发酵果蔬的功能及应用现状

随着消费者对健康饮食的日益重视,具有保健作用的发酵果蔬汁相关产品引起了研究者的广泛关注。果蔬是微生物生长的理想基质,果蔬汁发酵后会产生丰富的营养物质和多种功能活性,因此实现了果蔬高值化利用,使得未来发酵果蔬汁系列产品有着广阔的应用市场。本文综述了果蔬汁的常见发酵方式,发酵后的生物活性成分、功能活性以及发酵对果蔬汁的品质改善作用,对发酵果蔬汁行业的发展具有一定的指导意义。     

鲜切果蔬变色及其控制技术研究进展

影响鲜切果蔬外观品质最主要因素之一是变色。变色不仅影响鲜切果蔬外观品质,而且会影响其营养价值、风味等。本文主要概述了鲜切果蔬主要变色现象,包括褐变、黄化、白变和脱绿等,阐述了几种变色的机制及极易出现这几种变色现象的鲜切果蔬种类,同时还综述了目前控制鲜切果蔬变色的技术,主要包括化学方法(如化学护色剂处理、可食性涂膜、天然植物提取液处理等)、物理方法(如低温贮藏、热处理、气调贮藏、超声波处理等)和综合处理方法,以期为以后相关研究者提供参考借鉴。     

Ultrasound decontamination of minimally processed fruits and vegetables

The effectiveness of power ultrasound for the microbial decontamination of minimally processed fruits and vegetables was studied. Reductions in Salmonella typhimurium attached to iceberg lettuce obtained by cleaning with water, chlorinated water, ultrasound with water and ultrasound with chlorinated water were 0.7, 1.7, 1.5 and 2.7 logs, respectively, for small-scale (2 L) trials. The cleaning action of cavitation appears to remove cells attached to the surface of fresh produce, rendering the pathogens more susceptible to the sanitizer. For large-scale (40 L) trials, the addition of chlorine to water in the tank gave a systematic difference in Escherichia coli decontamination efficiency. However, the frequency of ultrasound treatment (25, 32–40, 62–70 kHz) had no significant effect on decontamination efficiency ( P  > 0.69). With the potentially high capital expenditure together with the expensive process of optimization and water treatment, it is unlikely that the fresh produce industry would be willing to take up this technology. Furthermore, the additional one log reduction achieved by applying ultrasound to a chlorinated water wash does not completely eliminate the risk of pathogens on fresh produce.     

果实和蔬菜中的过氧化物酶

介绍了果实和蔬菜中过氧化物酶催化的反应 ,过氧化物酶的底物、最适 p H和最适温度 ,过氧化物酶的热失活与酶的恢复和再生 ,过氧化物酶的化学物质抑活。     

Impact of Diet on Breast Cancer Risk: A Review of Experimental and Observational Studies

Breast cancer, which presents the highest global incidence of all female cancers, is caused by the interaction of genetic and environmental factors. Among the latter, diet has attracted considerable attention, as it is a modifiable risk factor and thus offers an opportunity to design preventive strategies. Nevertheless, only alcohol consumption has been unequivocally related to increased breast cancer risk. Despite the failure of observational studies in human populations to clearly define the nature of the relationship between specific nutrient exposures and breast cancer risk, in vivo and in vitro studies strongly suggest its existence. Moreover, studies at the molecular level have identified the putative action mechanism by which the nutritional constituents of specific foodstuffs may exert protective or enhancing effects with respect to breast cancer risk. The inadequate experimental design of some observational studies, or the occurrence of measurement errors and/or recall bias during data collection, or insufficient follow-up and subject characterization, may underlie these controversies. By improving the methods used to study the relationship between diet and breast cancer risk, and by applying new technologies linked to novel approaches such as “nutrigenomics,” it might be possible to derive effective recommendations for breast cancer prevention and thus improve anti-cancer treatment.     

微波干燥技术在食品工业中的应用研究

微波干燥技术是一种应用在食品工业的快速脱水新技术。介绍了近年来微波干燥技术在谷类、果蔬和水产品等食品原料中的应用技术研究,分析了现状及存在的问题,提出了微波干燥技术在食品工业中的应用研究可能发展的方向。     

Advances in Edible Coatings for Fresh Fruits and Vegetables: A Review

Edible coatings are an environmentally friendly technology that is applied on many products to control moisture transfer, gas exchange or oxidation processes. Edible coatings can provide an additional protective coating to produce and can also give the same effect as modified atmosphere storage in modifying internal gas composition. One major advantage of using edible films and coatings is that several active ingredients can be incorporated into the polymer matrix and consumed with the food, thus enhancing safety or even nutritional and sensory attributes. But, in some cases, edible coatings were not successful. The success of edible coatings for fresh products totally depends on the control of internal gas composition. Quality criteria for fruits and vegetables coated with edible films must be determined carefully and the quality parameters must be monitored throughout the storage period. Color change, firmness loss, ethanol fermentation, decay ratio and weight loss of edible film coated fruits need to be monitored. This review discusses the use of different edible coatings (polysaccharides, proteins, lipids and composite) as carriers of functional ingredients on fresh fruits and vegetables to maximize their quality and shelf life. This also includes the recent advances in the incorporation of antimicrobials, texture enhancers and nutraceuticals to improve quality and functionality of fresh-cut fruits. Sensory implications, regulatory status and future trends are also reviewed.     

果蔬保鲜技术及其研究进展

随着经济的发展和人们生活水平的提高,果蔬保鲜技术受到了社会各界的广泛关注,综述了果蔬保鲜技术的应用,并结合了近年来研究对一些新兴的保鲜技术进行介绍。此外,也对未来保鲜技术的发展做出了展望。     

渝东北地区常见果蔬中6种农药残留量分析与安全性评价

目的 了解渝东北地区果蔬中6种农药的残留现状及其对当地居民存在的健康风险。方法 利用气相色谱仪并结合食品安全指数分析法（index of food safety,IFS）对6种农药进行检测和安全性评价。结果 6种农药中狄氏剂未被检出,其余5种农药均被检出。5种农药在7类果蔬中平均残留量分别为腐霉利0.265 mg/kg、联苯菊酯0.037 mg/kg、高效氯氟氰菊酯0.073 mg/kg、氯氰菊酯0.060 mg/kg和溴氰菊酯0.025 mg/kg。其中高效氯氟氰菊酯在所有样品中检出率最高（25.34%）,其次是腐霉利（18.46%）,溴氰菊酯检出率最低（5.52%）;高效氯氟氰菊酯超标率最高（1.00%）,其次是腐霉利（0.90%）,超标率最低的是溴氰菊酯（0.09%）。安全性评价研究显示,5种检出农药的单种农药平均安全指数和多种农药平均安全指数均小于1。结论 渝东北市售果蔬样品对人体无显著风险。