Advances in innovative processing technologies for microbial inactivation and enhancement of food safety – pulsed electric field and low-temperature plasma

The need for enhancing microbial food safety and quality, without compromising the nutritional, functional and sensory characteristics of foods, has created an increasing world-wide interest in low-temperature innovative processes for food preservation. In contrast, to the traditional thermal processes, these emerging technologies are predominantly reliant on physical processes, including high hydrostatic pressures, pulsed electric fields and low-temperature plasmas that inactivate microorganisms at ambient or moderately elevated temperatures and short treatment times. The current review presents the latest developments in the two most recent of these technologies, pulsed electric field and low-temperature plasma treatments for food preservation and disinfection of food contact surfaces.     

Current status of emerging food processing technologies in Latin America: Novel non-thermal processing

Non-thermal emerging technologies in the sector of food processing have often been cited by researchers as an alternative to conventionally heat treatments for food processing in order to develop safe foods with minimal damage to nutritional and sensory properties. Non-thermal emerging technologies for foods processing have been widely developed in Europe and U.S.A. However, the interest in these technologies and commercialisation opportunities started catching up in Latin America. Thus, this review describes the basic principles and main effect of this technologies in the food and the recent scientific reports on its applications and potential advantages of the so-called non-thermal emerging technologies like ultrasound, high hydrostatic pressure, pulsed electric field, ionising radiation and atmospheric cold plasma, as alternative food preservation process. This review focuses on the current status in Latin America of novel non-thermal food processing technologies, highlighting the limits for scaling up to industrial level in order to be commercially successful.     

Nonthermal preservation of foods using combined processing techniques

In the last 2 decades, consumer demand for fresher, higher quality, and safer food has promoted research on nonthermal methods of food preservation for the inactivation of microorganisms and enzymes as an alternative to thermal processes. However, the high resistance of certain enzymes and microorganisms to nonthermal processes, especially bacterial spores, limit their application. To expand the use of nonthermal processes in the food industry, combinations of these technologies with traditional or emerging food preservation techniques are being studied. The use of nonthermal processes in combination with other preservation technologies presents a number of potential benefits to food preservation. The purpose of this article is to review some successful combinations of different nonthermal technologies, such as high hydrostatic pressure, ultrasound, pulsed electric fields, and irradiation, with traditional or emerging food preservation technologies.     

非热杀菌技术在冷链生鲜食品中杀菌消毒的研究进展

新型冠状病毒在全球范围内大流行，冷链生鲜食品及外包装作为新型冠状病毒潜在远程传播载体，增加了病毒通过“物传人”的感染风险。非热杀菌技术是一类新型杀菌技术，无需热能消耗即可杀灭食品中有害或致病微生物，避免了传统热杀菌技术传热相对较慢和对杀菌对象产生热损伤等缺点，将该技术应用于生鲜食品中不仅能有效阻断病毒传播，还能在食品保鲜和延长货架期方面发挥积极作用。本文主要介绍了适用于冷链环节中生鲜食品表面及外包装的非热杀菌技术，包括化学消毒剂、紫外线辐射、臭氧消毒、低温等离子体等，并从不同非热杀菌技术的工作机制、对病原体的灭活作用、对冷链过程中生鲜食品的保鲜效果进行阐述，以期为非热杀菌技术在冷链生鲜食品中的杀菌消毒应用提供理论指导，为保障冷链生鲜食品安全提供一定参考。     

Nonthermal physical technologies to decontaminate and extend the shelf-life of fruits and vegetables: Trends aiming at quality and safety

Minimally processed fruits and vegetables are one of the major growing sectors in food industry. This growing demand for healthy and convenient foods with fresh-like properties is accompanied by concerns surrounding efficacy of the available sanitizing methods to appropriately deal with food-borne diseases. In fact, chemical sanitizers do not provide an efficient microbial reduction, besides being perceived negatively by the consumers, dangerous for human health, and harmful to the environment, and the conventional thermal treatments may negatively affect physical, nutritional, or bioactive properties of these perishable foods. For these reasons, the industry is investigating alternative nonthermal physical technologies, namely innovative packaging systems, ionizing and ultraviolet radiation, pulsed light, high-power ultrasound, cold plasma, high hydrostatic pressure, and dense phase carbon dioxide, as well as possible combinations between them or with other preservation factors (hurdles). This review discusses the potential of these novel or emerging technologies for decontamination and shelf-life extension of fresh and minimally processed fruits and vegetables. Advantages, limitations, and challenges related to its use in this sector are also highlighted.     

Nonthermal Processes for Shelf‐Life Extension of Seafoods: A Revisit

For the past two decades, consumer demand for minimally processed seafoods with good sensory acceptability and nutritive properties has been increasing. Nonthermal food processing and preservation technologies have drawn the attention of food scientists and manufacturers because nutritional and sensory properties of such treated foods are minimally affected. More importantly, shelf‐life is extended as nonthermal treatments are capable of inhibiting or killing both spoilage and pathogenic organisms. They are also considered to be more energy‐efficient and to yield better quality when compared with conventional thermal processes. This review provides insight into the nonthermal processing technologies currently used for shelf‐life extension of seafoods. Both pretreatments such as acidic electrolyte water and ozonification and processing technologies, including high hydrostatic pressurization, ionizing radiation, cold plasma, ultraviolet light, and pulsed electric fields, as well as packaging technology, particularly modified atmosphere packaging, have been implemented to lower the microbial load in seafood. Thus, those technologies may be the ideal approach for the seafood industry, in which prime quality is maintained and safety is assured for consumers.     

Environmental impact of novel thermal and non-thermal technologies in food processing

During the last 25 years, consumer demands for more convenient and varied food products have grown exponentially, together with the need for faster production rates, improved quality and extension in shelf life. These requests together with the severity of the traditional food processing technologies were driving forces for improvements in existing technologies and for the development of new food preservation technologies. Therefore, many technological developments have been directed towards unit operations such as pasteurization, sterilization, cooking and drying, and currently the new technological approaches for food preservation are serious candidates to replace the traditional well-established preservation processes. The aim of this review is to discuss the environmental impact that some of the most promising novel food preservation technologies may represent in terms of energy efficiency, water savings and reduced emissions. The emergence of novel thermal and non-thermal technologies allows producing high quality products with improvements in terms of heating efficiency and, consequently, in energy savings. Most of these technologies are locally clean processes and therefore appear to be more environment-friendly, having less environmental impact than the traditional ones. Novel processing technologies are increasingly attracting the attention of food processors once they can provide food products with improved quality and a reduced environmental footprint, while reducing processing costs and improving the added-value of the products.     

Consumer perceptions of foods processed by innovative and emerging technologies: A conjoint analytic study

Conjoint analytic surveys were administered to 225 potential consumers of foods processed by innovative and emerging food technologies in order to assess the factors contributing to their interest in using such products. Respondents included 1) a consumer panel of civilian lab employees, 2) shoppers in a mall in the northeastern U.S., and 3) U.S. military troops on training exercises. Respondents rated their interest in 49 different food product concepts that varied in food type, processing or production technology, costs, benefits, risks, endorsing agencies, and product information. Results showed that the relative importance of factors did not vary greatly among the consumer groups. Perceived risks associated with the technologies were the most important factors influencing interest in use. Among the emerging technologies assessed, irradiation and genetic modification resulted in the greatest negative effect on likely use, while high pressure processing produced the most positive effect. The term “cold preservation” had positive associations for all groups, but “minimally processed” had negative associations. Implications of the data for the marketing of foods processed by innovative and emerging technologies are discussed.Industrial relevanceThe food industry is currently interested in a variety of novel production and processing technologies that may result in economical and improved quality products. However, consumer attitudes toward and conceptions of these new technologies can greatly influence their success in the marketplace. The results of this study show that “perceived risks” of the technologies are the most important determinant of interest in their use by consumers. This and other data uncovered in this study suggest that industry must be vigilant in their knowledge of consumer attitudes toward these processes in order to avoid unexpected failure of these products upon market introduction.     

Inactivation of Alicyclobacillus contaminans spores by dielectric barrier discharge plasma and its biological mechanism

Over the years, as an emerging technology, cold plasma (CP) has been widely used in the preservation of agricultural products. Alicyclobacillus spp. are spore-forming bacteria and difficult to inactivate. They adversely affect the economic value of agricultural products. Nevertheless, there are still few studies related to the inactivation of spores using CP. Herein, the inactivation effect and mechanism of dielectric barrier discharge plasma (DBDP) on Alicyclobacillus contaminans (A. contaminans) spores in phosphate-buffered saline and clarified apple juice were investigated. Plasma treatment at 75 V for 9 min achieved 99% inactivation of spores with the initial inocula of 7.13 and 5.72-log in PBS and apple juice, respectively. And the cell structure of the spores was severely disrupted leading to the leakage of the entocyte. Moreover, the surface properties of the spores were altered, making the adhesion of the spores to the hydrophobic surfaces and the stability of the bacterial suspension decreased leading to more agglomeration of the spores. Further results confirmed the intracellular homeostasis of the spores was also disrupted. Therefore, the inactivation mechanism of DBDP on spores was revealed from different perspectives, and our discoveries promote the theoretical progress in the use of plasma in food sterilization.Industrial relevanceAs an emerging nonthermal preservation technology, cold plasma has been used in food processing. In this study, we confirmed the feasibility of the inactivation of Alicyclobacillus contaminans spores in apple juice by dielectric barrier discharge plasma (DBDP) and investigated the mechanism of plasma inactivation of spores at the molecular biology level. This paper provides preliminary support for the application of low-temperature plasma in food processing such as apple juice.     

Application of High Pressure with Homogenization,Temperature, Carbon Dioxide,and Cold Plasma for the Inactivation of Bacterial Spores: A Review

Formation of highly resistant spores is a concern for the safety of low‐acid foods as they are a perfect vehicle for food spoilage and/or human infection. For spore inactivation, the strategy usually applied in the food industry is the intensification of traditional preservation methods to sterilization levels, which is often accompanied by decreases of nutritional and sensory properties. In order to overcome these unwanted side effects in food products, novel and emerging sterilization technologies are being developed, such as pressure‐assisted thermal sterilization, high‐pressure carbon dioxide, high‐pressure homogenization, and cold plasma. In this review, the application of these emergent technologies is discussed, in order to understand the effects on bacterial spores and their inactivation and thus ensure food safety of low‐acid foods. In general, the application of these novel technologies for inactivating spores is showing promising results. However, it is important to note that each technique has specific features that can be more suitable for a particular type of product. Thus, the most appropriate sterilization method for each product (and target microorganisms) should be assessed and carefully selected.     

生鲜食品冷链过程中消毒杀菌技术的研究进展

本文旨在概述适用于新冠肺炎疫情阶段且可同时用于冷链过程中生鲜食品表面及外包装的消毒杀菌技术,并讨论其现存的问题,为研发更加安全高效的消毒杀菌技术,实现更有效的疫情防控提供参考。本文主要从臭氧杀菌技术和紫外线杀菌技术的工作机理、对新型冠状病毒的灭活作用、对冷链过程中生鲜食品保鲜效果的影响、食品外包装消毒的有效性及应用现状进行论述。臭氧杀菌技术和紫外线杀菌技术对新型冠状病毒的灭活、生鲜食品表面及外包消毒具有积极作用,在新冠疫情期间具有较大的应用前景。但由于臭氧和紫外线具有一定的物理化学特性限制,加快臭氧覆盖速度与挥发时间、避免紫外线对低温贮藏食物有机分子结构的破坏以及探究其他冷杀菌技术在疫情阶段的适用性是今后的研究方向。     

基于电磁波和等离子体的固态食品新兴物理杀菌技术研究现状与展望

固态食品的杀菌是食品行业一直以来面临的关键技术难题。为保证杀菌过程的节能、高效、安全,近年来,围绕电磁波和等离子体等太空极端环境中的两大物理学现象涌现出一系列新兴物理杀菌技术,其中包括以催化式红外、微波、射频等为代表的热物理杀菌技术和以光动力、脉冲强光、低温等离子体活化水/冰、包装内低温等离子体等为代表的非热物理杀菌技术。这些新兴技术可适应不同形态、不同组分特征的固态食品的表面或整体杀菌。重点梳理了相关技术的核心问题和最新应用研究,并从4个方面提出了未来固态食品物理杀菌技术的主要研究任务:1)深化物理杀菌技术的机制研究。以不同的固态食品基质环境为基础,探明不同的食源性微生物在不同物理场胁迫下的响应机制。2)推动多物理场耦合的杀菌关键技术攻关。根据不同的固态食品物料特征,协同多种各具特色的新兴物理杀菌技术,在杀菌有效性和食品品质减损之间建立平衡。3)突破物理杀菌关键装备的制造瓶颈。在学科交叉的基础上,攻克物理杀菌关键装备研发的卡脖子技术,最大限度降低制造成本。4)促进包装内物理杀菌技术的开发与应用。根据固态食品生产的真实场景,促进包装内物理杀菌技术装备的研发,避免杀菌后的二次污染。     

Emerging food processing technologies and factors impacting their industrial adoption

Abstract

Innovative food processing technologies have been widely investigated in food processing research in recent years. These technologies offer key advantages for advancing the preservation and quality of conventional foods, for combatting the growing challenges posed by globalization, increased competitive pressures and diverse consumer demands. However, there is a need to increase the level of adoption of novel technologies to ensure the potential benefits of these technologies are exploited more by the food industry. This review outlines emerging thermal and non-thermal food processing technologies with regard to their mechanisms, applications and commercial aspects. The level of adoption of novel food processing technologies by the food industry is outlined and the factors that impact their industrial adoption are discussed. At an industry level, the technological capabilities of individual companies, their size, market share as well as their absorptive capacity impact adoption of a novel technology. Characteristics of the technology itself such as costs involved in its development and commercialization, associated risks and relative advantage, and level of complexity and compatibility influence the technology's adoption. The review concludes that a deep understanding of the development and application of a technology along with the factors influencing its acceptance are critical to ensure its commercial adoption.     

Principles and recent applications of novel non-thermal processing technologies for the fish industry—a review

Thermal treatment is a traditional method for food processing, which can kill microorganisms but also lead to physicochemical and sensory quality damage, especially to temperature-sensitive foods. Nowadays consumers’ increasing interest in microbial safety products with premium appearance, flavor, great nutritional value and extended shelf-life has promoted the development of emerging non-thermal food processing technologies as alternative or substitution to traditional thermal methods. Fish is an important and world-favored food but has a short shelf-life due to its extremely perishable characteristic, and the microbial spoilage and oxidative process happen rapidly just from the moment of capture, making it dependent heavily on post-harvest preservation. The applications of novel non-thermal food processing technologies, including high pressure processing (HPP), ultrasound (US), pulsed electric fields (PEF), pulsed light (PL), cold plasma (CP) and ozone can extend the shelf-life by microbial inactivation and also keep good sensory quality attributes of fish, which is of high interest for the fish industry. This review presents the principles, developments of emerging non-thermal food processing technologies, and also their applications in fish industry, with the main focus on microbial inactivation and sensory quality. The promising results showed great potential to keep microbial safety while maintaining organoleptic attributes of fish products. What’s more, the strengths and weaknesses of these technologies are also discussed. The combination of different food processing technologies or with advanced packaging methods can improve antimicrobial efficacy while not significantly affect other quality properties under optimized treatment.     

新型热和非热食品加工技术的研究进展及影响其工业应用的因素

近年来,新型食品加工技术在食品加工领域的广泛研究应用,为推进传统食品保存,缓解因消费者需求多样化所带来的压力提供了有力保障。本文简述了新型热和非热食品加工技术的机制、工业应用和商业价值,概述并讨论新型食品加工技术的研究进展和影响其工业应用的因素。从生产水平上看,公司的技术、规模、市场份额和资金吸纳能力会影响新型技术在工业上的应用。从技术层面看,新型技术本身的特征,如技术开发的成本,相关风险和相对优势等也会影响新型加工技术的普及。因此本文深入分析新型热和非热食品加工技术的开发、应用以及影响其接受度的因素,这对新型热和非热食品加工技术的商业化利用至关重要。     

水产品辐射保鲜技术研究进展

鲜度是水产品重要的品质指标,是决定其价格的主要因素。辐射保鲜技术作为一种新兴的食品保藏技术,其原理是利用电离辐射辐照各种水产品进行杀虫、灭菌和抑制某些生理活动来延长水产品的贮存期。作者对水产品辐射保鲜技术的特点、辐射剂量对水产品品质的影响以及辐射保鲜技术的安全性问题进行了综述,对水产品辐射保鲜技术的发展前景提供了新的思路,并进行了展望。     

Preserving quality of fresh-cut products using safe technologies

Food preservation is critical for keeping the global food supply safe and available for consumers. Food scientists study production and processing to develop new technologies that improve the quality and quantity of healthy food products, with the main objective of increasing food production without affecting food quality and environment, while fulfilling consumer expectations. Nowadays consumers want their food to be fresh, nutritious, safe, and attractive, low priced, and ready-to-eat. That is the case of fresh-cut products; however, maintaining the quality of these products is not an easy task, since minimally processed products experience increased ethylene production and respiration rates, with the consequent lost of quality. New effective and inexpensive technologies to safely preserve the quality of fresh-cut products are needed. In the last two decades, food scientists have attempted to solve problems in fresh-cut processing and quality preservation, and rapid advances in scientific knowledge on fresh-cut product preservation have been developed. The present review describes the use of emerging technologies such as ultraviolet irradiation (UV-C), edible coatings, active packaging and natural additives, to preserve the quality of fresh-cut fruits; highlighting the areas in which information is still lacking, and commenting on future trends.     

Detoxification of hazelnuts by different cold plasmas and gamma irradiation treatments

The detoxification effects of cold atmospheric-pressure (AP,3000 L/h of air, 25 kHz, 655 W-1.7 min) and low-pressure (LP,air-100 W-30 min) plasmas and gamma irradiation(GMI,10 kGy-10 min) treatments on different concentrations of pure aflatoxin B1(AFB1) and AFB1 + B2 (TotAFs) as well as same toxins spiked on hazelnut were investigated. Both plasmas reduced 72–73% of AFB1 (3 ppb) spiked on hazelnuts while GMI reduced 47% of AFB1. TotAFs (6 ppb) reductions on hazelnut after both plasmas were 70–71%, which was also higher than that of GMI (15.5%). However, the reductions in pure AFB1 at 1–50 ppb and TotAFs at 1.03–51.5 ppb after GMI (97–100%) were higher than those of AP (55–75%) and LP (69–90%) plasmas. AP plasma has the potential to be an alternative to conventional detoxification methods because it is both effective on aflatoxins in foods and maintains the sensory attributes of food evaluated by a sensory panel.Industry relevanceThe use of plasma technology in foods for detoxification purposes is an economic alternative to conventional and other non-thermal processes as well as meeting the industry's demand for sustainable development. This study showed that different cold plasmas are capable of reducing the aflatoxins as pure forms as well as in food. The results contributed to the understanding of cold plasma detoxification effects on aflatoxins and could be a basis for a possible industrial implementation.     

国内外蓝莓保鲜技术研究进展

综述了国内外蓝莓保鲜技术的研究进展,包括冷藏保鲜、气调保鲜、涂膜保鲜、1-MCP熏蒸保鲜、UV-C辐射保鲜等,特别是对应用性较强、易于产业化的气调保鲜技术研究现状作重点介绍,并结合生产实际,对我国蓝莓保鲜技术发展方向进行展望。