Cold plasma an emerging nonthermal technology for milk and milk products: A review

Combined effect of cold plasma-activated oxygen (CPAO) and microwave on microbial decontamination and quality of milkshake powder

This study presents a new method combining cold plasma-activated oxygen (CPAO) and microwave (MW) to decontaminate milkshake powder, exploring its effectiveness, mechanisms, and quality impact. CPAO (6 min) alone reduced bacterial load by 0.419 log CFU/g, and MW (3 min) by 0.030 log CFU/g. However, their co-application significantly amplified decontamination, achieving a 1.265 log CFU/g reduction. CPAO-MW co-treatment inflicted more oxidative damage on bacterial cell membranes and intracellular antioxidant defense system, leading to higher mortality. It also raised protein and lipid oxidation, while decreasing vitamin C and A levels in the powder. Specifically, CPAO (6 min)-MW (3 min) co-treatment increased the carbonyl content from 0.438 to 0.891 nmol/mg protein, malondialdehyde from 0.824 to 0.996 mg/kg, and lowered vitamin C from 162.151 to 137.640 mg/kg, and vitamin A from 2.05 to 1.38 mg/kg. This study shows CPAO-MW is effective for decontaminating powdered foods but highlights a need to reduce negative effects.

Recent developments in ultrasound approach for preservation of animal origin foods

Ultrasound is a contemporary non-thermal technology that is currently being extensively evaluated for its potential to preserve highly perishable foods, while also contributing positively to the economy and environment. There has been a rise in the demand for food products that have undergone minimal processing or have been subjected to non-thermal techniques. Livestock-derived food products, such as meat, milk, eggs, and seafood, are widely recognized for their high nutritional value. These products are notably rich in proteins and quality fats, rendering them particularly vulnerable to oxidative and microbial spoilage. Ultrasound has exhibited significant antimicrobial properties, as well as the ability to deactivate enzymes and enhance mass transfer. The present review centers on the production and classification of ultrasound, as well as its recent implementation in the context of livestock-derived food products. The commercial applications, advantages, and limitations of the subject matter are also subject to scrutiny. The review indicated that ultrasound technology can be effectively utilized in food products derived from livestock, leading to favorable outcomes in terms of prolonging the shelf life of food while preserving its nutritional, functional, and sensory attributes. It is recommended that additional research be conducted to investigate the effects of ultrasound processing on nutrient bioavailability and extraction. The implementation of hurdle technology can effectively identify and mitigate the lower inactivation of certain microorganisms or vegetative cells.

The use of cold plasma technology in solving the mold problem in Kashar cheese

In this study, the possibilities of using cold plasma technology in solving the mold problem, which is one of the most important problems in Kashar cheese, were investigated. For this purpose Kashar cheeses were exposed to cold plasma with different gas compositions. As a result of the study 3-4 log reduction was achieved for both Aspergillus flavus and Penicillium crysogenum. The pH and aw values of samples were decreased with cold plasma application. The b* values of samples increased while L* and a* values decreased. When all the results obtained are considered as a whole, it can be said that cold plasma technology improves the physicochemical properties of Kashar cheese and provides significant decrease in mold count of the product.

Modeling the UV-C Inactivation Kinetics and Determination of Fluence Required for Incremental Inactivation of Cronobacter spp

ABSTRACT

A study was undertaken to model the UV-C inactivation kinetics and determine the fluences required for the incremental inactivation of several strains of Cronobacter spp. suspended in clear phosphate-buffered saline (PBS). In total, 13 strains of Cronobacter spp. were individually suspended in PBS and treated with UV-C doses of 0, 2, 4, 6, 8, and 10 mJ cm-2 with a collimated beam device emitting UV-C at 253.7 nm. The log reduction from each treatment was identified using the plate count method and plotted against the UV-C dose and then curve fitted using several mathematical models. The UV-C dose required for incremental inactivation of each isolate was determined using both linear and nonlinear regression. For the 13 strains tested, a UV-C dose of 10 mJ cm-2 inactivated between 3.66 ± 0.101 and 5.04 ± 0.465 log CFU mL-1. The survival behavior of all strains was best fitted to the Weibull+tail model, with correlation coefficients between 97.17 and 99.71%, and was used to determine the fluences required for incremental inactivation. The UV-C fluences needed to inactivate 1 log (D10-value) of Cronobacter spp. in buffer were between 3.53 and 5.50 mJ cm-2, whereas a fluence greater than 6.57 mJ cm-2 was required to achieve a 4-log inactivation. A clear understanding of the UV-C dose-response of several strains of Cronobacter spp. lays the foundation to design effective UV-based disinfection systems.

HIGHLIGHTS

Comparison of the Effect of Cold Plasma with Conventional Preservation Methods on Red Wine Quality Using Chemometrics Analysis

In this study, the effect of cold plasma (CP) on the physicochemical and biological properties of red wine was investigated in comparison with the effects of the conventional preservation method and the combined method. In addition, the effect of storage time after the application of each of the analyzed methods was evaluated. The study examined the effects of the different preservation methods on the pH, color, phenolic content, antioxidant activity and microbiological purity of the red wine. Chemometric analysis was used to discover the relationship between the preservation method used and wine quality. In the wine samples tested, a reduction in phenolic compounds and a decrease in antioxidant activity were noted after storage. This effect was mildest for preservation methods with the addition of potassium metabisulphite and those in which a mixture of helium and nitrogen was used as the working gas. On a positive note, the CP treatment did not affect the color of the wine in a way perceptible to the consumer: ∆E*—1.12 (He/N₂; 5 min). In addition, the lowest growth of microorganisms was detected in the CP-treated samples. This indicates the potential of cold plasma as an alternative method to the use of potassium metabisulfite in wine production, which may contribute to its wider use in the alcohol industry in the future.

Possibilities of using the continuous type of UV light on the surface of lor (whey) cheese: impacts on mould growth, oxidative stability, sensory and colour attributes during storage

This research paper addresses the hypothesis that the optimum doses of a continuous type of ultraviolet (UV) light applied to the surface of lor (whey) cheese needs to be identified to maximize mould inactivation and shelf life while minimizing quality deterioration. Therefore, the mould inactivation, protein and lipid oxidation products, sensory and colour attributes of lor cheese subjected to different doses of UV light (1.617, 4.018, and 36.832 kJ/m2) in a continuous type of UV system were evaluated. UV treated samples presented mould counts lower than those of untreated ones. UV treatment at more than 4.018 kJ/m2 allowed around 0.7-2.7 log reductions on mould growth during storage. The increase in UV light dose caused significant increases in primary and secondary lipid oxidation products. In particular, the highest doses applied to the surface of cheese samples had the highest values of protein carbonyls, as well as lipid oxidation products. Strong positive correlations were recorded between lipid and protein oxidation markers. Exposure to the highest doses of UV light increased foreign flavour perception, probably due to the oxidative reactions. The results indicated that the application of UV light to the lor cheese surface allowed delaying mould growth during storage but extreme doses could induce lipid and protein oxidation reactions, leading to quality deterioration.

Recent developments in the use of cold plasma, high hydrostatic pressure, and pulsed electric fields on microorganisms and viruses in seafood

Non-thermal processing methods, such as cold plasma (CP), high pressure processing (HPP) and pulsed electric fields (PEF), have been proposed for natural and fresh-like foods to inactivate microorganisms at nearly-ambient or moderate temperature. Since natural, safe, and healthy foods with longer shelf-life are increasingly demanded, these requests are challenging to fulfill by using current thermal processing technologies. Thus, novel preservation technologies based on non-thermal processing methods are required. The aim of this article is to provide recent developments in maintaining seafood safety via CP, HHP, and PEF technologies, as well as their mechanisms of action regarding contamination with food-borne microorganisms. Their application to control parasites, spores and the possibility to eradicate the hazard of SARS-CoV-2 transmission through seafood products are also discussed. CP, HHP, and PEF have been applied to inactivate food-borne microorganisms in the seafood industry. However, the drawbacks for each emerging technology have also been reported. To ensure safety and maintain quality of seafood products, the combination of these processing techniques with natural antimicrobial agents or existing thermal methods may be more applicable in the case of the seafood industry. Further studies are required to examine the effects of these methods on viruses, parasites, and SARS-CoV-2 in seafood.

Non-thermal Processing Technologies for Dairy Products: Their Effect on Safety and Quality Characteristics

Thermal treatment has always been the processing method of choice for food treatment in order to make it safe for consumption and to extend its shelf life. Over the past years non-thermal processing technologies are gaining momentum and they have been utilized especially as technological advancements have made upscaling and continuous treatment possible. Additionally, non-thermal treatments are usually environmentally friendly and energy-efficient, hence sustainable. On the other hand, challenges exist; initial cost of some non-thermal processes is high, the microbial inactivation needs to be continuously assessed and verified, application to both to solid and liquid foods is not always available, some organoleptic characteristics might be affected. The combination of thermal and non-thermal processing methods that will produce safe foods with minimal effect on nutrients and quality characteristics, while improving the environmental/energy fingerprint might be more plausible.

Recent trends and technological development in plasma as an emerging and promising technology for food biosystems

The rising need for wholesome, fresh, safe and “minimally-processed” foods has led to pioneering research activities in the emerging non-thermal technology of food processing. Cold plasma is such an innovative and promising technology that offers several potential applications in the food industry. It uses the highly reactive, energetic and charged gas molecules and species to decontaminate the food and package surfaces and preserve the foods without causing thermal damage to the nutritional and quality attributes of food. Cold plasma technology showed promising results about the inactivation of pathogens in the food industry without affecting the food quality. It is highly effective for surface decontamination of fruits and vegetables, but extensive research is required before its commercial utilization. Recent patents are focused on the applications of cold plasma in food processing and preservation. However, further studies are strongly needed to scale up this technology for future commercialization and understand plasma physics for getting better results and expand the applications and benefits. This review summarizes the emerging trends of cold plasma along with its recent applications in the food industry to extend shelf life and improve the quality of food. It also gives an overview of plasma generation and principles including mechanism of action. Further, the patents based on cold plasma technology have also been highlighted comprehensively for the first time.

Revisiting Non-Thermal Food Processing and Preservation Methods-Action Mechanisms, Pros and Cons: A Technological Update (2016-2021)

The push for non-thermal food processing methods has emerged due to the challenges associated with thermal food processing methods, for instance, high operational costs and alteration of food nutrient components. Non-thermal food processing involves methods where the food materials receive microbiological inactivation without or with little direct application of heat. Besides being well established in scientific literature, research into non-thermal food processing technologies are constantly on the rise as applied to a wide range of food products. Due to such remarkable progress by scientists and researchers, there is need for continuous synthesis of relevant scientific literature for the benefit of all actors in the agro-food value chain, most importantly the food processors, and to supplement existing information. This review, therefore, aimed to provide a technological update on some selected non-thermal food processing methods specifically focused on their operational mechanisms, their effectiveness in preserving various kinds of foods, as revealed by their pros (merits) and cons (demerits). Specifically, pulsed electric field, pulsed light, ultraviolet radiation, high-pressure processing, non-thermal (cold) plasma, ozone treatment, ionizing radiation, and ultrasound were considered. What defines these techniques, their ability to exhibit limited changes in the sensory attributes of food, retain the food nutrient contents, ensure food safety, extend shelf-life, and being eco-friendly were highlighted. Rationalizing the process mechanisms about these specific non-thermal technologies alongside consumer education can help raise awareness prior to any design considerations, improvement of cost-effectiveness, and scaling-up their capacity for industrial-level applications.