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The study investigated the effects of pilot-scale plasma activated water (PAW) on the inactivation of Escherichia coli O157:H7, Salmonella Typhimurium, Listeria monocytogenes , and indigenous mesophilic aerobic bacteria on romaine lettuce and steamed rice cake (SRC). PAW treatment was conducted by stirring 25 g of romaine lettuce and 80 g of SRC for 20–40 min at 195 rpm in 1 L of PAW, prepared by treating sterile distilled water with surface dielectric barrier discharge for 40 or 60 min. The microbial inactivation rates of foodborne pathogens and indigenous mesophilic aerobic bacteria ranged from 1.3 to 2.5 log on romaine lettuce and SRC, along with PAW generation time (P < 0.05). Inactivation rates of PAW generation time or treatment time against romaine lettuce and SRC were significantly different to the inactivation of distilled water treatments, respectively (P < 0.05). The pH, electrical conductivity, and hydrogen ion concentration correlated with nitrite and nitrate concentrations of PAW prepared at various PAW generation time. In situ pilot-scale PAW treatment also extended the shelf life of the romaine lettuce. The study demonstrates the feasibility of the pilot-scale PAW treatment to improve microbiological safety and its suitability of applying PAW to manufacture romaine lettuce and SRC products. • Pilot-scale plasma activated water (PAW) effectively decontaminates romaine lettuce and steamed rice cake (SRC). • PAW generation time significantly decontaminates romaine lettuce and SRC (P < 0.05). • Decontamination rates of romaine lettuce and SRC did not significantly different within treatment times (P > 0.05). • The physicochemical properties of PAW increased with generation time and remain constant for 1 h. • Pilot scale PAW extended the microbial stability compared to commercially prepared romaine lettuce. [ABSTRACT FROM AUTHOR]

Dielectric barrier discharge atmospheric cold plasma (DACP) treatment was evaluated for the inactivation of Escherichia coli O157:H7, surface morphology, color, carbon dioxide generation, and weight loss of bulk Romaine lettuce in a commercial plastic clamshell container. The lettuce samples were packed in a model bulk packaging configuration (three rows with either 1, 3, 5, or 7 layers) in the container and treated by DACP (42.6 kV, 10 min). DACP treatment reduced the number of E. coli O157:H7 in the leaf samples in the 1-, 3-, and 5-layer configurations by 0.4–0.8 log CFU/g lettuce, with no significant correlation to the sample location ( P > 0.05). In the largest bulk stacking with 7 layers, a greater degree of reduction (1.1 log CFU/g lettuce) was observed at the top layer, but shaking the container increased the uniformity of the inhibition. DACP did not significantly change the surface morphology, color, respiration rate, or weight loss of the samples, nor did these properties differ significantly according to their location in the bulk stack. DACP treatment inhibited E. coli O157:H7 on bulk lettuce in clamshell containers in a uniform manner, without affecting the physical and biological properties and thus holds promise as a post-packaging process for fresh and fresh-cut fruits and vegetables. [ABSTRACT FROM AUTHOR]

Abstract: Antimicrobial films were developed using defatted soybean meal (DSM), a by-product left after crushing soybeans for oil, and the lactoperoxidase system (LPOS). Effects of the composition of the films on physical and antimicrobial properties of the films and the diffusion of antimicrobial hypothiocyanite (OSCN−) from the LPOS in the films were investigated. The antimicrobial DSM film inhibited Salmonella (4 log CFU/cm2) on agar media. Yellowness and elongation of the film increased, while lightness and the elastic modulus decreased as the concentration of protein increased in the film. The composition of the films did not affect their antimicrobial activity. The diffusion of antimicrobial OSCN− in the film increased with increasing concentrations of glycerol or protein in the film, storage temperature, or water activity of the food on which the film was applied, and thus the film can be formulated to achieve a necessary antimicrobial release rate. The composition of the DSM can be used to predict the physical and diffusion properties of the DSM-based antimicrobial films prepared from different DSMs. The DSM film coating did not significantly affect the sensory properties of sliced ham (P > 0.05), demonstrating the potential for the application to commercial ham products. [Copyright &y& Elsevier]

Abstract: Edible films were developed from potato peel. High-pressure, gamma-ray, and ultrasound were applied to potato peel solutions to break down biopolymer particles in the solution small enough to allow for biopolymer film formation. Film properties, including moisture barrier and tensile properties, color, and microstructures, were investigated from the films formed with different concentrations of plasticizer (glycerol) and emulsifier (soy lecithin). High-pressure homogenization (HPH) produced the best films among the treatments at the conditions used in this research. Water vapor permeability (WVP) of films decreased by 32% with decrease in the concentrations of glycerol and soy lecithin by 40 and 75%, respectively. As the concentration of glycerol or soy lecithin increased, tensile strength of the films decreased up to 71%, but the elongation at break increased up to 161%, demonstrating lubricant effects of glycerol and soy lecithin. The lightness and yellowness of the films increased and the redness decreased with increase in the concentration of glycerol or soy lecithin. The concentrations of glycerol and soy lecithin were identified as important variables in producing biopolymer films from potato peel. [Copyright &y& Elsevier]

The bactericidal effects of a self-designed device that combines intense pulsed light (IPL), plasma, and ultraviolet irradiation (UV) on granular and powdered foods, and the changes induced in the properties of the samples were studied. Samples were treated by combined IPL-plasma-UV system continuously. A maximum 1.33 ± 0.24-log reduction of microorganisms on sesame seeds were achieved using the combined system, while maximum 1.12 ± 0.18- and 0.59 ± 0.06-reductions were achieved using IPL-only and plasma-only systems, respectively. Using the combined system achieved maximum 0.41 ± 0.04- and 0.51 ± 0.05-log reductions of microorganisms on black pepper powder and red pepper powder, respectively, which have more holes, cracks, and crevices than sesame seeds. Significant changes in water activity, moisture content, and color were found in all samples due to drying caused by fast circulation or plasma treatment. So further research is needed to reduce the changes of the sample properties after the combined system. • IPL-plasma-UV combined device to decontaminate powdered foods has been constructed. • Higher biocidal effects than the IPL-only and plasma-only systems were shown. • Maximum 1.33 log reduction of microbial inactivation was achieved in sesame seeds. • Sample with smooth surfaces and a few clogged holes had greater inactivation. [ABSTRACT FROM AUTHOR]

Effects of the microwave-powered cold plasma treatments (CPTs) on the inhibition of microorganisms in red pepper powder, including Aspergillus flavus and Bacillus cereus spores, were investigated. Combinations of heat treatment with CPT were investigated for the inhibition of B. cereus spores on the powder. The number of A. flavus was reduced by 2.5 ± 0.3 log spores/g by the CPT with nitrogen at 900 W and 667 Pa for 20 min. CPT at 900 W and 667 Pa for 20 min inhibited naturally occurring total aerobic bacteria in the red pepper powder by approximately 1 log CFU/g. B. cereus spores were inhibited (3.4 ± 0.7 log spores/g reduction) only when heat treatment at 90 °C for 30 min was integrated with the CPT using a helium-oxygen gas mixture at 900 W. Fermi's model and Weibull model adequately described the inhibition of A. flavus on the red pepper powder by the CPT. The changes in treatment temperature and water activity were less than 5.0 °C (initial temperature: 23.8 °C) and 0.22, respectively, and were affected by both treatment power and time (P < 0.05). The CPTs have demonstrated the potential to reduce the microbial counts of red pepper powder and other powder products. [ABSTRACT FROM AUTHOR]

The effects of microwave-integrated cold plasma (CP) treatments against spores of Bacillus cereus and Aspergillus brasiliensis and Escherichia coli O157:H7 on onion powder were investigated. The growth of B. cereus , A. brasiliensis , and E. coli O157:H7 in the treated onion powder was assessed during storage at 4 and 25 °C, along with the physicochemical and sensory properties of the powder. Onion powder inoculated with B. cereus was treated with CP using helium as a plasma-forming gas, with simultaneous exposure to low microwave density at 170 mW m −2 or high microwave density at 250 mW m −2 . High microwave density-CP treatment (HMCPT) was more effective than low microwave density-CP treatment (LMCPT) in inhibiting B. cereus spores, but induced the changes in the volatile profile of powder. Increase in treatment time in HMCPT yielded greater inhibition of B. cereus spores. Vacuum drying led to greater inhibition of spores of B. cereus and A. brasiliensis than hot-air drying. HMCPT at 400 W for 40 min, determined as the optimum conditions for B. cereus spore inhibition, initially reduced the numbers of B. cereus , A. brasiliensis , and E. coli O157:H7 by 2.1 log spores/cm 2 , 1.6 log spores/cm 2 , and 1.9 CFU/cm 2 , respectively. The reduced number of B. cereus spores remained constant, while the number of A. brasiliensis spores in the treated powder increased gradually during storage at 4 and 25 °C and was not different from the number of spores in untreated samples by the end of storage at 4 °C. The E. coli counts in the treated powder fell below the level of detection after day 21 at both temperatures. HMCPT did not affect the color, antioxidant activity, or quercetin concentration of the powder during storage at both temperatures. The microwave-integrated CPTs showed potential for nonthermal decontamination of onion powder. [ABSTRACT FROM AUTHOR]

Effects of lemongrass oil (LO) droplet size in the LO/chitosan emulsion on the emulsion's coating effectiveness in improving microbiological safety and preserving grape berries ( Vitis vinifera L. × V. labruscana Bailey) were investigated. LO was homogenized with a chitosan solution (1 g/100 g) and Tween 20 (0.25 g/100 g) by high shear mixing (HSM; 10,000 rpm, 1 min) or dynamic high pressure processing (DHP; 103–172 MPa, 1–3 passes), forming LO coating emulsions. The particle sizes of the HSM and DHP emulsions were 461.9–632.6 nm and 204.2–378.8 nm, respectively. DHP emulsions were more stable than HSM emulsions. Compared with the HSM emulsion, the DHP emulsion coating resulted in higher initial inhibition of Salmonella typhimurium ; greater growth inhibition of total mesophilic aerobes, yeasts, and molds; and retention of color, total soluble solid content, and antioxidant activity during storage at 25 °C ( P < 0.05). The sensory results suggest that the DHP emulsion minimized differences in sensory attributes compared with uncoated grape berries more effectively than did the HSM emulsion coating. The nanoemulsion coating with smaller LO droplets demonstrated greater efficiency in increasing microbial safety against Salmonella and preserving grape berries, compared with the coating with larger droplets. [ABSTRACT FROM AUTHOR]

Microwave-powered cold plasma treatment (CPT) was evaluated as a means to improve the microbiological safety of fresh vegetables and dried fruits. The CPT at 900 W, conducted for 10 min using nitrogen as a plasma-forming gas, inactivated Salmonella Typhimurium inoculated on cabbage and lettuce by approximately 1.5 log CFU/g. The CPT at 400–900 W and 667 Pa, conducted for 1–10 min using a helium–oxygen gas mixture, inactivated Listeria monocytogenes on cabbage by 0.3–2.1 log CFU/g in a time-dependent manner (P < 0.05). The Weibull model adequately described the inactivation of L. monocytogenes on cabbage by CPT. The CPT at the optimum conditions of treatment power (400 W) and time (10 min) inactivated L. monocytogenes on lettuce by 1.8 ± 0.2 log CFU/g. As the water activity of the dried figs increased from 0.70 to 0.93, the reductions in numbers of Escherichia coli O157:H7 and L. monocytogenes on figs increased from 0.5 to 1.3 log CFU/g and from 1.0 to 1.6 log CFU/g, respectively. The microbial inactivation by CPT increased synergistically when the pH of the figs was reduced from 6 to 4. CTPs have potential application to increase the microbiological safety of vegetables and dried fruits. [ABSTRACT FROM AUTHOR]

Abstract: Grape berries are highly perishable and vulnerable to contamination with foodborne pathogens. Nanoemulsions of lemongrass oil (LO) were developed for coating of grape berries (Vitis labruscana Bailey) to improve the shelf life and microbiological safety. Vortex mixing, high-shear probe mixing, and dynamic high pressure (DHP) processing were tested as methods of incorporating LO into a carnauba-based solution (0.5–4.0 g/100 g LO). The coating solutions produced by DHP demonstrated the highest emulsion stability and resulted in uniform and continuous coatings on grape berries. The coating on the berries with 3.0 g/100 g LO initially inhibited Salmonella typhimurium and Escherichia coli O157:H7 inoculated on the berries by more than 3.2 and 2.6 log CFU/g, respectively. The coatings did not significantly alter the flavor of the berries and improved their glossiness. Antimicrobial effects against S. typhimurium and E. coli O157:H7 were exhibited during storage at 4 and 25 °C for 28 days. The coatings were also effective on reducing losses of weight, firmness, phenolic compounds, and antioxidant activity and delaying increases in total anthocyanin concentration in the berries. The LO-nanoemulsion coatings have demonstrated the potential to inhibit foodborne pathogen contamination of grape berries, and prolong their shelf life. [Copyright &y& Elsevier]

Abstract: A carnauba-shellac wax (CSW)-based nanoemulsion containing lemongrass oil (LO) was prepared using high pressure homogenization. ‘Fuji’ apples were coated with the CSW/LO nanoemulsion and the coated apple samples were compared with uncoated apple samples with respect to quality and microbial safety for 5 months. During storage, the hardness of the uncoated apples decreased by 3.3 N, and the weight loss was 7.7%. In contrast, the hardness of the coated apples did not change, and the weight loss was 5.2%. Titratable acidity and total soluble solids were not significantly different between coated and uncoated apples. The apples coated with the CSW/LO solution had the best sensory appreciations. After 5 months of storage, the population of total aerobic bacteria on the coated apples was decreased by 1.4 log CFU/g compared with the uncoated apples. In addition, the population of yeast and molds on the uncoated apples was 2.2 log CFU/g after 5 months of storage, whereas yeast and molds were not detected on the coated apples. The CSW/LO coating can improve the quality of ‘Fuji’ apples during storage. [Copyright &y& Elsevier]

This study investigated the effects of plasma-activated water (PAW) treatment parameters on the inactivation of indigenous mesophilic aerobic bacteria and coliform bacteria on steamed rice cake (SRC). PAW treatment was conducted by washing SRC with PAW, prepared by treating sterilized distilled water with surface dielectric barrier discharge plasma at 16 kV. The plasma discharge time and SRC mass significantly affected the efficacy of microbial inactivation. The optimum treatment conditions (28.7 min of discharge time, 29.0 min of treatment time, and 155.5 g of SRC) did not alter the color and firmness of the SRC. The results demonstrated that the antimicrobial activity of PAW was more due to the presence of plasma reactive species than due to low pH. Furthermore, PAW treatment inhibited the growth of indigenous mesophilic aerobic bacteria much more effectively than NaClO (0.2 g/L) solution treatments. This study demonstrated the potential of using PAW treatment to improve the microbiological stability of SRC. • Plasma-activated water (PAW) effectively decontaminates steamed rice cake (SRC). • Both discharge time and SRC mass affect the inactivation efficacy of PAW treatment. • Optimized PAW treatment does not affect the color and texture of SRC. • The PAW activity is due more to plasma reactive species than to low pH. • PAW washing is more effective than NaClO washing in inhibiting the microbial growth. [ABSTRACT FROM AUTHOR]

This study investigated the efficacy of atmospheric dielectric barrier discharge in-package cold plasma treatment (ADCPT) in inactivating Escherichia coli O157:H7, Salmonella , Listeria monocytogenes , and Tulane virus (TV) in whey protein-coated boiled chicken breast (BCB) cubes. The optimal ADCPT conditions for Salmonella inactivation were determined, and the effects of ADCPT on lipid oxidation and color were also evaluated. The optimal ADCPT voltage and time for Salmonella inactivation were found to be 39 kV and 3.5 min, respectively, resulting in a reduction of 3.7 log CFU/cube. Further, these conditions effectively inactivated E. coli O157:H7 (3.9 log CFU/cube), L. monocytogenes (3.5 log CFU/cube), and TV (2.2 PFU/cube). A second-order polynomial model can be used to explain the inactivation of Salmonella. ADCPT did not significantly affect the values of thiobarbituric acid reactive substance or color of BCB. Thus, these results suggest that ADCPT is an effective method for enhancing the microbiological safety of ready-to-eat packaged BCB by inactivating major foodborne pathogens and human norovirus without affecting the lipid oxidation and color of BCB. Image 1 • Cold plasma (CP) effectively inactivates the foodborne pathogens on chicken samples. • In-package CP effectively inactivates Tulane virus, a human norovirus surrogate. • CP effectively decontaminates chicken samples in commercial plastic containers. • Microbial inactivation data are explained by the investigated mathematical models. • CP does not affect the sample's color, lipid oxidation, and protein degradation. [ABSTRACT FROM AUTHOR]

This study investigated the effects of washing and packaging combined treatments on satsuma mandarin (Citrus unshiu Marc.) quality during storage at 4 °C and 25 °C. The treatments involved the combinations of washing using calcium oxide (CaO, 0.2%) solution, carnauba wax coating with grapefruit seed extract (1%) (CW coating), and modified atmosphere packaging (MAP) using O 2 –CO 2 –N 2 (9.9%, 2.1%, and 88.0%, respectively). The growth of P. digitatum was inhibited across all samples at 4 °C and 25 °C. CaO washing delayed the increase in mandarin CO 2 generation during storage at both temperatures and the decrease in antioxidant capacity at 4 °C. CW coating retarded the increase in CO 2 generation and the decrease in firmness and antioxidant capacity at both temperatures. MAP delayed the decrease in ascorbic acid concentration at 25 °C and the increase in CO 2 generation at 4 °C and 25 °C and also retarded the reduction in antioxidant capacity with or without CaO washing at both temperatures. The combination of three treatments effectively delayed decreases in firmness, ascorbic acid concentration, and antioxidant capacity, and retarded increases in the CO 2 generation of mandarins during storage, which demonstrates the potential effectiveness of combined treatments in extending the shelf life of mandarins. • The combined treatment systems developed in the study increase mandarin storability. • The CaO washing, wax coating, and MAP combined treatment is most effective. • This treatment suppresses mandarin respiration rates during storage. • This treatment controls the loss of firmness and ascorbic acid and antioxidant levels. • The use of this technology is anticipated to extend the shelf life of citrus fruits. [ABSTRACT FROM AUTHOR]

We evaluated the effect of plasma-activated water (PAW) on the populations of foodborne pathogens and food-spoilage microorganisms on Korean rice cake. PAW was produced by treating distilled water with two atmospheric dielectric-barrier discharges (51.7 W, 14.4 kHz, air discharge) for 20 min. The inactivation effect of PAW on indigenous microorganism and inoculated Escherichia coli O157:H7, Salmonella Typhimurium, Listeria monocytogenes , Penicillium chrysogenum and Candida albicans on Korean rice cake were measured and their effect on the color and texture values of the samples were determined. PAW treatment for 20 min reduced the numbers of the three foodborne pathogens by about 2.0 log CFU/g. PAW treatment for 20 min reduced the numbers of total aerobes, P. chrysogenum, and C. albicans by 2.78, 1.97, and 1.00 log CFU/g, respectively. The antimicrobial effect of PAW was not significantly different from 0.2 ppm of sodium hypochlorite solution, which is used in Korean rice cake production. PAW treatment did not affect the color, texture, or pH of Korean rice cake. Therefore, PAW treatment can be used as an alternative method to reduce safety risk and spoilage of Korean rice cake without deteriorating its quality. • Plasma activated water (PAW) were used to pasteurize Korean rice cake. • PAW treatment on Korean rice cakes showed ~2 log CFU/g on foodborne pathogens, total aerobes, and a food spoilage fungi. • PAW showed similar inactivation rate compared to 0.2 ppm of sodium hypochlorite solutions. • The quality changes of Korean rice cake subjected to PAW treatment were not observed. [ABSTRACT FROM AUTHOR]