Application of ultraviolet radiation and ultrasound treatments for Alicyclobacillus acidoterrestris spores inactivation in apple juice

Antibacterial Activity and Transcriptomic Analysis of Hesperetin against Alicyclobacillus acidoterrestris Vegetative Cells

The aim of this research was to investigate the antimicrobial characteristics and mechanism of hesperetin against Alicyclobacillus acidoterrestris vegetative cells. The results presented show that hesperetin had effective antimicrobial activity on Alicyclobacillus acidoterrestris vegetative cells, minimum inhibition concentration (MIC) of 0.0625 g/L, and minimum bacterial concentration (MBC) greater than 2 g/L. Moreover, treatment of hesperetin caused significant damage to cell integrity, preventing the growth of Alicyclobacillus acidoterrestris vegetative cells, enhancing the leakage of nucleic acid and proteins, and destroying the vegetative cell morphology. To further investigate the mechanism, transcriptomic analysis was carried out, and 3056 differentially expressed genes (DEGs) were detected. Gene ontology (GO) enrichment analysis revealed that hesperetin inhibits Alicyclobacillus acidoterrestris by affecting the intracellular nitrogen metabolism and amino acid metabolism. The Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis explained that hesperetin was also able to prevent the growth of Alicyclobacillus acidoterrestris by affecting the processes of nutrient transport, energy metabolism, and flagella motility. These results provide new insights into the antimicrobial effects and mechanism of hesperetin against Alicyclobacillus acidoterrestris, which provides a new method for inactive Alicyclobacillus acidoterrestris in the juice industry.

Microbial decontamination assisted by ultrasound-based processing technologies in food and model systems: A review

Ultrasound (US) technology is recognized as one of the emerging technologies that arise from the current trends for improving nutritional and organoleptic properties while providing food safety. However, when applying the US alone, higher power and longer treatment times than conventional thermal treatments are needed to achieve a comparable level of microbial inactivation. This results in risks, damaging food products' composition, structure, or sensory properties, and can lead to higher processing costs. Therefore, the US has often been investigated in combination with other approaches, like heating at mild temperatures and/or treatments at elevated pressure, use of antimicrobial substances, or other emerging technologies (e.g., high-pressure processing, pulsed electric fields, nonthermal plasma, or microwaves). A combination of US with different approaches has been reported to be less energy and time consuming. This manuscript aims to provide a broad review of the microbial inactivation efficacy of US technology in different food matrices and model systems. In particular, emphasis is given to the US in combination with the two most industrially viable physical processes, that is, heating at mild temperatures and/or treatments at elevated pressure, resulting in techniques known as thermosonication, manosonication, and manothermosonication. The available literature is reviewed, and critically discussed, and potential research gaps are identified. Additionally, discussions on the US's inactivation mechanisms and lethal effects are included. Finally, mathematical modeling approaches of microbial inactivation kinetics due to US-based processing technologies are also outlined. Overall, this review focuses only on the uses of the US and its combinations with other processes relevant to microbial food decontamination.

Inactivation of Alicyclobacillus acidoterrestris spores, single or composite Escherichia coli and native microbiota in isotonic fruit-flavoured sports drinks processed by UV-C light

Pasteurized sports drinks and other fruit-based beverages are susceptible to deterioration due to thermal processing ineffectiveness to inactivate certain spoilage microorganisms, like Alicyclobacillus acidoterrestris. This represents a major challenge for the beverage industry. The goals of this study were to: i) investigate the UV-C inactivation (annular thin film unit, actinometrical delivered fluence: 795-1270 mJ/cm², 10-15 min, 20 °C, 1.8 L/h, Re_h = 391-1067, recirculation mode operation) and the evolution during refrigerated storage of A. acidoterrestris ATCC 49025 spores and single or composite Escherichia coli ATCC 25922 in isotonic sports drinks (ISDs) made from orange (orange-ISD, UVT% = 81) or orange-banana-mango-kiwi-strawberry-lemon juices (multi-fruit-ISD, UVT% = 91), compared to a turbid orange-tangerine juice (OT juice, UVT% = 40); ii) assess the effect of pH, °Brix, A_254nm, turbidity, colour and particle size of the ISDs and juice on microbial inactivation, iii) evaluate the evolution of native microbiota during cold storage, iv) investigate the Coroller, biphasic, Weibull, and Weibull-plus-tail models' ability to describe microbial inactivation and v) measure 5-hydroxymethylfurfural (HMF) formation. The modified biodosimetry method was used to calculate the germicidal UV-C fluences. Heat pasteurization (T-coil, 80 °C/6 min) was evaluated as the control treatment. UV-C was highly effective at inactivating E. coli as 4.1-5.1 and 4.5-5.6 log reductions were determined in the multi-fruit-ISD and orange-ISD, respectively, barely impacted by the background microbiota. No significant differences were recorded for the inactivation of E. coli in the UV-C and T-coil systems. Whereas, a significantly higher inactivation of A. acidoterrestris spores was achieved by UV-C (3.7-4.0 log reductions), compared to the negligible one achieved by the thermal treatment. Even though E. coli inactivation curves were similar in shape, UV-C was less effective when a cocktail of other E. coli strains was present. In comparison to the OT juice, the ISDs' inactivation kinetics were markedly different in shape, with a rapid decrease in population during the first minutes of treatment. The germicidal fluence (H_{d biod}) corresponding to A. acidoterrestris (19.1 mJ/cm²) was selected as it was higher than the one obtained for E. coli (11.0 mJ/cm²). UV-C induced 2.8- or 1.3 and 2.3- or 0.8 log-reductions of total aerobes or moulds and yeasts in the multi-fruit-ISD and orange-ISD, respectively. Compared to the other models, the Coroller and biphasic models showed a better fit and more accurate parameter estimates. UV-C-induced HMF production was not significant in the ISDs. The current study found that the UV-C treatment was more effective than typical heat pasteurization for inactivating A. acidoterrestris spores in isotonic drinks, following a similar trend for E. coli and native microbiota.

Application and potential of multifrequency ultrasound in juice industry: Comprehensive analysis of inactivation and germination of Alicyclobacillus acidoterrestris spores

The majority of acidic fruits are perishable owing to their high-water activity, which promotes microbial activity, thus exhibiting metabolic functions that cause spoilage. Along with sanitary practices, several treatments are used during processing and/or storage to inhibit the development of undesirable bacteria. To overcome the challenges caused by mild heat treatment, juice manufacturers have recently increased their involvement in developing novel non-thermal processing procedures. Ultrasonication alone or in combination with other hurdle technologies may be used to pasteurize processed fruit juices. Multifrequency ultrasound has gained popularity due to the fact that mono-frequency ultrasound has less impact on bacterial inactivation and bioactive compound enhancement of fruit juice. Here, we present and discuss the fundamental information and technological knowledge of how spoilage bacteria, specifically Alicyclobacillus acidoterrestris, assemble resistant spores and inactivate and germinate dormant spores in response to nutrient germinants and physical treatments such as heat and ultrasound. To the authors' knowledge, no prior review of ultrasonic inactivation and germination of A. acidoterrestris in fruit juice exists. Therefore, this article aims to provide a review of previously published research on the inactivation and germination of A. acidoterrestris in fruit juice by ultrasound and heat.

Purification and Characterization of Plantaricin YKX and Assessment of Its Inhibitory Activity Against Alicyclobacillus spp

Consumers prefer natural over synthetic chemical preservatives on a food label. Therefore, it is crucial to ensure the safety and efficacy of such natural preservatives. The emergence of heat-resistant spore-forming Alicyclobacillus spp. has been associated with spoilage problems in the fruit juice industry. Herein, a bacteriocin-producing stain YKX was isolated from the traditional pickles in Hanzhong City, China, and it was identified as Lactobacillus plantarum by morphological, biochemical, physiological, and genotypic features. A stable bacteriocin, plantaricin YKX, was isolated, purified, and tested for its efficacy against Alicyclobacillus acidoterrestris. Plantaricin YKX is a 14-amino acid peptide (Lys-Tyr-Gly-Asn-Gly-Leu-Ser-Arg-Ile-Phe-Ser-Ala-Leu-Lys). Its minimal inhibitory concentrations (MICs) against the tested bacterial and fungal strains were ranged from 16 to 64 μg/mL. It is thermostable and active at pH 3-8. The flow cytometry data and microscopic observations suggested that plantaricin YKX can augment cell membrane permeability, induce potassium ion leakage and pore formation, and disrupt cell membranes. It also affects spore germination and guaiacol production of A. acidoterrestris, probably due to upregulation of the luxS gene linked to quorum sensing.

Bacteriostatic effects of high-intensity ultrasonic treatment on Bacillus subtilis vegetative cells

The bacteriostatic effects of high-intensity ultrasonic treatment (HIU) on Bacillus subtilis vegetative cells were evaluated, and the related mechanisms were explored using quantitative proteomics. The bacteriostatic effect of HIU on B. subtilis was proportional to the ultrasound treatment time and power, and the number of cultivable B. subtilis cells was decreased by approximately one log (at 270 W for 15 min) or half log (at 90 W for 25 min or 360 W for 5 min). Scanning electron microscopy images and gel electrophoresis results showed that HIU caused the destruction of the cell structure and intracellular protein leakage. In addition, HIU treatment at 270 W for 15 min resulted in the greatest decrease (84.22%) in intracellular adenosine triphosphate (ATP) content. The quantitative proteomic analysis showed that B. subtilis resisted the stress of HIU treatment by regulating the key proteins in physiological activities related to membrane transport (ATP-binding cassette [ABC] transporter), signal transduction (the two-component system), and energy metabolism (the tricarboxylic acid [TCA] cycle). HIU-induced physical damage, stress, and metabolic disorders were the main causes of the bacteriostatic effects on B. subtilis. These findings provide a foundation for the subsequent optimization and potential applications of HIU inactivation of B. subtilis.

Phytochemical Fortification in Fruit and Vegetable Beverages with Green Technologies

BACKGROUND

Phytochemical, bioactive and nutraceutical compounds are terms usually found in the scientific literature related to natural compounds found in plants linked to health-promoting properties. Fruit and vegetable beverages (mainly juice and smoothies) are a convenient strategy to enhance the consumption of horticultural commodities, with the possibility of being fortified with plant byproducts to enhance the content of bioactive compounds.

OBJECTIVE

This review aims to analyse the different green technologies applied in beverage processing with a fortification effect on their health promoting compounds.

RESULTS

Fortification can be performed by several strategies, including physical elicitors (e.g., processing technologies), plant/algae extract supplementation, and fermentation with probiotics, among others. Thermal processing technologies are conventionally used to ensure the preservation of food safety with a long shelf life, but this frequently reduces nutritional and sensory quality. However, green non-thermal technologies (e.g., UV, high-pressure processing, pulsed electric fields, ultrasounds, cold plasma, etc.) are being widely investigated in order to reduce costs and make possible more sustainable production processes without affecting the nutritional and sensory quality of beverages.

CONCLUSIONS

Such green processing technologies may enhance the content of phytochemical compounds through improvement of their extraction/bioaccessibility and/or different biosynthetic reactions that occurred during processing.

Bacterial Spore Inactivation in Orange Juice and Orange Peel by Ultraviolet-C Light

Spore-forming bacteria are a great concern for fruit juice processors as they can resist the thermal pasteurization and the high hydrostatic pressure treatments that fruit juices receive during their processing, thus reducing their microbiological quality and safety. In this context, our objective was to evaluate the efficacy of Ultraviolet-C (UV-C) light at 254 nm on reducing bacterial spores of Alicyclobacillus acidoterrestris, Bacillus coagulans and Bacillus cereus at two stages of orange juice production. To simulate fruit disinfection before processing, the orange peel was artificially inoculated with each of the bacterial spores and submitted to UV-C light (97.8-100.1 W/m²) with treatment times between 3 s and 10 min. The obtained product, the orange juice, was also tested by exposing the artificially inoculated juice to UV-C light (100.9-107.9 W/m²) between 5 and 60 min. A three-minute treatment (18.0 kJ/m²) reduced spore numbers on orange peel around 2 log units, while more than 45 min (278.8 kJ/m²) were needed to achieve the same reduction in orange juice for all evaluated bacterial spores. As raw fruits are the main source of bacterial spores in fruit juices, reducing bacterial spores on fruit peels could help fruit juice processors to enhance the microbiological quality and safety of fruit juices.

An Overview of the Factors Influencing Apple Cider Sensory and Microbial Quality from Raw Materials to Emerging Processing Technologies

Given apple, an easily adapted culture, and a large number of apple varieties, the production of apple cider is widespread globally. Through the fermentation process, a series of chemical changes take place depending on the apple juice composition, type of microorganism involved and technology applied. Following both fermentations, alcoholic and malo-lactic, and during maturation, the sensory profile of cider changes. This review summarises the current knowledge about the influence of apple variety and microorganisms involved in cider fermentation on the sensory and volatile profiles of cider. Implications of both Saccharomyces, non-Saccharomyces yeast and lactic acid bacteria, respectively, are discussed. Also are presented the emerging technologies applied to cider processing (pulsed electric field, microwave extraction, enzymatic, ultraviolet and ultrasound treatments, high-pressure and pulsed light processing) and the latest trends for a balanced production in terms of sustainability, authenticity and consumer preferences.

Aplicação do ultrassom no processamento de frutas e hortaliças

Resumo Este trabalho objetivou apresentar aspectos relacionados à utilização do ultrassom no processamento de frutas e hortaliças, como o funcionamento do método, os efeitos no alimento, as aplicações, os aspectos sensoriais e a percepção dos consumidores. As mudanças dos hábitos alimentares e a busca do bem-estar refletem no aumento da procura por alimentos naturais, como as frutas e as hortaliças. Estes alimentos podem sofrer alterações microbiológicas ao longo da cadeia produtiva, sendo necessária a aplicação de boas práticas agrícolas e de manipulação, e processos tecnológicos de conservação para a garantia da qualidade do produto. O ultrassom é uma tecnologia emergente aplicada no processamento de frutas e hortaliças que está relacionada a melhorias na qualidade e preservação. O princípio básico do ultrassom é a cavitação acústica, que envolve o crescimento e colapso de bolhas durante períodos de rarefação e compressão, causando alterações químicas, físicas e mecânicas no alimento. Essas alterações estão relacionadas à inativação de micro-organismos e de enzimas, à remoção de resíduos e às melhorias na qualidade físico-química, e à acessibilidade de compostos bioativos. Além disso, a aplicação deste método pode ter boa aceitabilidade pelos consumidores, que procuram alimentos mais naturais e submetidos a processos que não causem impacto ambiental.

Effects of ultraviolet-C light-emitting diodes at 275 nm on inactivation of Alicyclobacillusacidoterrestris vegetative cells and its spores as well as the quality attributes of orange juice

Alicyclobacillus acidoterrestris is a thermoacidophilic, spore-forming bacillus. A. acidoterrestris and its spores can survive in pasteurized juices and cause microbial spoilage. In this work, the effects of ultraviolet-C light-emitting diodes at 275 nm on the inactivation of A. acidoterrestris vegetative cells and its spores in commercial pasteurized orange juice were studied. Meanwhile, the effects of ultraviolet-C light-emitting diodes on the quality attributes of the orange juice were also investigated. The quantities of A. acidoterrestris vegetative cells and its spores inoculated in orange juice were reduced by 6.04 and 2.49 log₁₀ CFU/mL after ultraviolet-C light-emitting diode treatment at 220 mJ/cm², respectively. The Weibull and Weibull plus tail models were satisfactorily fitted to estimate the reductions of A. acidoterrestris vegetative cells and its spores in orange juice, respectively. Physicochemical properties (pH, titratable acidity, total soluble solids, and clarity) of orange juice did not change significantly after exposure to ultraviolet-C light-emitting diodes. However, the total phenolic content of orange juice decreased with increasing fluence. In addition, ultraviolet-C light-emitting diode treatment at a higher fluence led to a noticeable color difference. These results indicate that ultraviolet-C light-emitting diode treatment has a potential application in the juice processing industry.

Compostable Polylactide and Cellulose Based Packaging for Fresh-Cut Cherry Tomatoes: Performance Evaluation and Influence of Sterilization Treatment

For food packaging, plastic materials display large appeal, mostly due to their versatility, mechanical, optical and barrier properties. However, they play an important role in environmental concerns and waste management issue. Compostable bioplastics represent alternative materials designed for a lower environmental impact. In this work, a biobased compostable packaging, constituted by polylactide (PLA) trays and NatureFlex™ film, was evaluated for fresh-cut cherry tomato. A comparative analysis was accomplished using traditional packaging materials, that is, polyethylene terephtalate (PET) trays and polypropylene (PP Coex) film. Structural stability under food contact conditions, mechanical and physical-chemical properties were investigated. Tensile mechanical properties, puncture resistance, contact angle (CA) and attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIR), before and after UV or radiofrequency (RF) sterilization treatment, were evaluated. UV irradiation method resulted the less invasive one. Therefore, oxygen and water vapor transmission rate (OTR and WVTR), overall chemical migration test, biodegradation assessment by biochemical oxygen demand (BOD) according to ISO 14851 and disintegration test by ISO 20200 were carried out to establish the further influence of UV sterilization on the packaging. Overall, data showed that the biobased compostable packaging for a prolonged shelf-life of fresh-cut cherry tomato has better properties that were surprisingly enhanced by the UV treatment.

Innovative Hurdle Technologies for the Preservation of Functional Fruit Juices

Functional nutrition, which includes the consumption of fruit juices, has become the field of interest for those seeking a healthy lifestyle. Functional nutrition is also of great interest to the food industry, with the aims of improving human health and providing economic prosperity in a sustainable manner. The functional food sector is the most profitable part of the food industry, with a fast-growing market resulting from new sociodemographic trends (e.g., longer life expectancy, higher standard of living, better health care), which often includes sustainable concepts of food production. Therefore, the demand for hurdle technology in the food industry is growing, along with the consumption of minimally processed foods, not only because this approach inactivates microorganisms in food, but because it can also prolong the shelf life of food products. To preserve food products such as fruit juices, the hurdle technology approach often uses non-thermal methods as alternatives to pasteurization, which can cause a decrease in the nutritional value and quality of the food. Non-thermal technologies are often combined with different hurdles, such as antimicrobial additives, thermal treatment, and ultraviolet or pulsed light, to achieve synergistic effects and overall quality improvements in (functional) juices. Hence, hurdle technology could be a promising approach for the preservation of fruit juices due to its efficiency and low impact on juice quality and characteristics, although all processing parameters still require optimization.

Effect of ultrasound combined with ultraviolet treatment on microbial inactivation and quality properties of mango juice

This work explored the effect of ultraviolet-assisted ultrasound (US-UV) as an emerging non-thermal sterilization technology on mango juice in aspects of microbial growth and quality changes. The juice in the ice bath was subjected to US-UV treatment at different US powers (0-600 W) and times (0-40 min), and no pathogen bacteria could be detected after treatment, while the physicochemical features (particle size, suspension stability, color, content of total polyphenols, carotenoids, sugar, reducing sugar and protein) and antioxidant ability of treated juice was preserved or improved to some extent. Based on these results, we further validated its positive effects on the nutritional value (content of ascorbic acid and soluble dietary fiber, antioxidant ability) and quality parameters (titratable acid, sugar acidity, total soluble solids, rheological behavior, metal elements) of mango juice treated at the optimal US parameter (10 min, 600 W); Not only the inactivation of polyphenol oxidation enzyme, peroxidase and pectin methylesterase was achieved but also the treated juice has a significant different volatile profile compared with the fresh juice, which might offer the better color, texture, and smell. Importantly, through the HPLC-MSD-Trap-XCT (phenols) and UPLC-Q Exactive Orbitrap-MS (carotenoids) study, the US-UV treatment will not cause difference on compounds composition, but it was responsible for changes in content of individual compounds, especially the all-trans-β-carotene, became the main component of carotenoids in processed mango juice (increased from 43.72% to 75.15%, relative content), and the oxygenated carotenoids (xanthophylls) are highly sensitive to the US (reduced from 50.96% to 4.85%) while the carotenes show a strong resistance to the US (increased 49.04% to 95.15%). Thus, the overall safety and quality of mango juice were enhanced while the sensory characteristics remained stable, suggesting that this non-thermal combination sterilization processing may successfully be implemented in the commercial processing of mango juice.

Hurdle enhancement of acidic electrolyzed water antimicrobial efficacy on Bacillus cereus spores using ultrasonication

This study evaluated the inactivation effect of ultrasonic treatment combined with acidic electrolyzed water (AEW) on Bacillus cereus spores. AEW treatment reduced the spores by 1.05-1.37 log CFU/mL while the sporicidal effect of ultrasound was minor. More strikingly, simultaneous ultrasonic and AEW treatments for 30 min led to 2.29 log CFU/mL reduction and thus, considered a synergistic effect. Flow cytometry combined with SYTO/PI staining analysis revealed that ultrasound hydrolyzed the cortex while the AEW partially damaged the integrity of the inner membrane. Scanning and transmission electron microscopies were used to characterize the ultrastructural changes. The detachment of the exosporium induced by ultrasound was the most apparent difference compared with the control group, and the electron density of spores appeared to be heterogeneous after treatment with AEW. These results indicated that combining ultrasound with AEW is a promising decontamination technology with potential uses in the food industry and environmental remediation.

Comparison of high temperature-short time and sonication on selected parameters of strawberry juice during room temperature storage

The purpose of current research was to explore the effect of high temperature-short time (HTST) and different ultrasound times intervals on the strawberry juice for a period of 14 days. Strawberry fruits were treated at 72 °C for 15 s by HTST and also sonicated at 20 kHz and 100% amplitude for 5, 10, and 15 min. The main objective is to evaluate the effect of treatments and storage time on color, total antioxidants, total phenolics, ascorbic acid and microbial content of strawberry juice. Results showed that the increase in the sonication treatment time (from 5 to 15 min) showed a higher total phenolics, antioxidant capacity and ascorbic acid content. In addition, 15 min sonicated-strawberry juices showed a higher lightness values as compared to HTST treated strawberry juice. Sonication treatment showed a potential as a method to preserve and improve the phytochemical quality of strawberry juice during room temperature storage.

Inactivation kinetics of Bacillus cereus spores by Plasma activated water (PAW)

In recent years, plasma activated water has attracted more attention as a new disinfectant. The purpose of this study was to explore impact of variation of different treatment conditions on the inactivation kinetics of Bacillus cereus spores by PAW. All survival curves showed that the number of spores has decreased rapidly at first, followed by tailing results from the reduction inactivation rate. A linear and two nonlinear models (Weibull and Log-logistic model) were fitted to these data, and Log-logistic model fitted the inactivation of the B. cereus spores best. B. cereus spores in 10⁶ CFU/mL was reduced by 1.62-2.96 log CFU/mL by PAW at 55 °C due to the reactive species generated in PAW. Elevated temperature, lower initial spore concentration, lower bovine serum albumin content, and smaller activation volume of PAW considerably enhanced PAW inactivation of B. cereus spores. These results provide an approach to evaluate the inactivation efficacy of different treatment conditions for PAW.

Effect of packaging methods and storage conditions on quality characteristics of flour product naan

The quality characteristics of naan from flour products under various packaging methods stored at different temperatures (25, 4 and - 20 °C) for different time (0-49 days) were investigated. Packaging methods included ordinary plastic packaging (OPP), vacuum packaging (VP) and deoxygenation packaging (DP). Sensory value, acid value, moisture content and microbial count of naan during storage were evaluated. The results showed that the total demerit points of sensory of DP naan stored at 25 °C had considerably lower levels. The moisture content of naan in DP and VP at 25 °C during storage had not been affected, while in OPP increased; the acid values of naan increased, but in DP was the lowest; the total microbiological count (MC) of naan in OPP, VP and DP at 5th day reached 2.25, 3.04 and 1.99 log CFU g^-1, respectively. At 4 and - 20 °C, the moisture content of naan in OPP, VP and DP during storage reduced, the acid values at storage the 38th day dramatically increased (p < 0.05), the MC slowly increased, but these in DP samples was lower. The Ultraviolet (UV) and microwave (MW) radiation time was varied to study its effect on the shelf life of naan at 25 °C. The moisture content of UV and MW treated naan were not significantly different from those of control naan (p > 0.05), but the demerit points, acid values and MC reduced, the shelf life of naan was extended. The combination of DP and MW methods was a better efficient way to reduced negative quality changes of naan during storage.

Effect of soluble solids concentration on Neosartorya fischeri inactivation using UV-C light

Ascospores of Neosartorya fischeri are heat-resistant and can survive thermal commercial treatments normally applied to the juices, as apple juice. Non-thermal processing of food such as exposure to ultraviolet light (UV-C) is reported to induce minimal quality changes while reduces microbial load. The main objective of this study was to determine the effect at different soluble solids concentration (12, 25, 30, 40, 50, 60 and 70 °Brix) on N. fischeri ascospores inactivation in apple juice, using UV-C light intensity (38 W/m²). Weibull model was fitted to experimental data. Then, a secondary model was used to describe how the inactivation kinetic parameters varied with the changes in soluble solids concentration. Results showed that the UV-C light had influence on N. fischeri ascospores inactivation in apple juice even at the highest soluble solids concentrations used, reaching approximately 4 log reductions at all concentrations used. The inactivation parameters, obtained by Weibull model, were δ (dose for the first decimal reduction) and p (the shape factor). Exponential model was chosen to describe the influence of soluble solids concentration on δ and p parameters. It can be concluded that UV-C light is a promising treatment with a drastic impact on the loads of N. fischeri, especially when low soluble solids concentration is used and a model was obtained to describe Brix effect.

Three Pillars of Novel Nonthermal Food Technologies: Food Safety, Quality, and Environment

This review gives an overview of the impact of novel nonthermal food technologies on food safety, on quality, and on the environment. It confirms that research in this field is mainly focused on analyzing microbial and/or chemical aspects of food safety. However, recent research shows that in spite of various food safety benefits, some negative (quality oriented) features occur. Finally, this paper shows the necessity of analyzing the environmental dimension of using these technologies.