In-package atmospheric cold plasma treatment of bulk grape tomatoes for microbiological safety and preservation

Min, Sea C.,Roh, Si Hyeon,Niemira, Brendan A.,Boyd, Glenn,Sites, Joseph E.,Fan, Xuetong,Sokorai, Kimberly,Jin, Tony Z. Elsevier 2018 Food Research International Vol.108 No.-

<P><B>Abstract</B></P> <P>Effects of dielectric barrier discharge atmospheric cold plasma (DACP) treatment on the inactivation of <I>Salmonella</I> and the storability of grape tomato were investigated. Grape tomatoes, with or without inoculation with <I>Salmonella</I>, were packaged in a polyethylene terephthalate (PET) commercial clamshell container and cold plasma-treated at 35 kV at 1.1 A for 3 min using a DACP system equipped with a pin-type high-voltage electrode. DACP treatment inactivated <I>Salmonella</I> (<I>p</I> < 0.05) without altering the color or firmness of the grape tomatoes (<I>p</I> > 0.05). DACP treatment inactivated <I>Salmonella</I> uniformly in both layers of the double-layer configuration of the grape tomatoes regardless of the position of the tomatoes in each layer. <I>Salmonella</I> was most efficiently inactivated when the headspace to tomato volume ratio of the container was highest. Integration of rolling of tomatoes during treatment significantly increased the <I>Salmonella</I> reduction rates from 0.9 ± 0.2 log CFU/tomato to 3.3 ± 0.5 log CFU/tomato in the double-layer configuration of the tomato samples. Rolling-integrated DACP also initially reduced the number of total mesophilic aerobic bacteria and yeast and molds in the double-layer configuration of tomato samples by 1.3 ± 0.3 and 1.5 ± 0.2 log CFU/tomato, respectively. DACP treatment effectively reduced the growth of <I>Salmonella</I> and indigenous microorganisms at 10 and 25 °C, and did not influence the surface color, firmness, weight loss, lycopene concentration and residual ascorbic acid of grape tomatoes during storage at 10 and 25 °C. DACP treatment holds promise as a post-packaging process for improving microbial safety against <I>Salmonella</I> and storability of fresh grape tomatoes.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Atmospheric cold plasma treatment (ACPT) inactivates <I>Salmonella</I> on grape tomatoes. </LI> <LI> A higher container headspace to tomato volume ratio results in higher inactivation. </LI> <LI> Inactivation is uniform with tomatoes in a 2-layer configuration in the container. </LI> <LI> Rolling of samples during ACPT increases <I>Salmonella</I> reduction rates. </LI> <LI> ACPT inhibits microbial growth during storage without affecting quality. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Inactivation of Escherichia coli O157:H7 and Aerobic Microorganisms in Romaine Lettuce Packaged in a Commercial Polyethylene Terephthalate Container Using Atmospheric Cold Plasma

MIN, SEA C.,ROH, SI HYEON,BOYD, GLENN,SITES, JOSEPH E.,UKNALIS, JOSEPH,FAN, XUETONG,NIEMIRA, BRENDAN A. ational Association for Food Protection 2017 Journal of food protection Vol.80 No.1

<B>ABSTRACT</B><P>The effects of dielectric barrier discharge atmospheric cold plasma (DACP) treatment on the inactivation of Escherichia coli O157:H7 and aerobic microorganisms in romaine lettuce packaged in a conventional commercial plastic container were evaluated during storage at 4°C for 7 days. Effects investigated included the color, carbon dioxide (CO2) generation, weight loss, and surface morphology of the lettuce during storage. Romaine lettuce pieces, with or without inoculation with a cocktail of three strains of E. coli O157:H7 (~6 log CFU/g of lettuce), were packaged in a polyethylene terephthalate commercial clamshell container and treated at 34.8 kV at 1.1 kHz for 5 min by using a DACP treatment system equipped with a pin-type high-voltage electrode. Romaine lettuce samples were analyzed for inactivation of E. coli O157:H7, total mesophilic aerobes, and yeasts and molds, color, CO2 generation, weight loss, and surface morphology during storage at 4°C for 7 days. The DACP treatment reduced the initial counts of E. coli O157:H7 and total aerobic microorganisms by ~1 log CFU/g, with negligible temperature change from 24.5 ± 1.4°C to 26.6 ± 1.7°C. The reductions in the numbers of E. coli O157:H7, total mesophilic aerobes, and yeasts and molds during storage were 0.8 to 1.5, 0.7 to 1.9, and 0.9 to 1.7 log CFU/g, respectively. DACP treatment, however, did not significantly affect the color, CO2 generation, weight, and surface morphology of lettuce during storage (P &gt; 0.05). Some mesophilic aerobic bacteria were sublethally injured by DACP treatment. The results from this study demonstrate the potential of applying DACP as a postpackaging treatment to decontaminate lettuce contained in conventional plastic packages without altering color and leaf respiration during posttreatment cold storage.</P>

Improvement of the Antioxidant Activity, Water Solubility, and Dispersion Stability of Prickly Pear Cactus Fruit Extracts Using Argon Cold Plasma Treatment

Kim, Su Yeon,Lee, Seung Young,Min, Sea C. Institute of Food Technologists 2019 Journal of Food Science Vol.84 No.10

<P> Microwave-powered cold plasma (CP) treatment was evaluated as a means to increase the antioxidant activity, water solubility, and dispersion stability of prickly pear cactus fruit <I>(Opuntia ficus-indica</I> (L.) Mill.) extract. The extract (2 g) was treated at various CP generation powers and treatment times at 25 °C to 28 °C. The antioxidant activity of the prickly pear cactus fruit extract increased by 1.8% and 1.7% after CP treatment at 750 W for 40 min and 856 W for 36 min, respectively. Both the water solubility and dispersion stability (delta backscattering) of the extract increased by 2.4% and 0.1%, respectively, following CP treatment at 644 W for 36 min. These results suggest the potential of CP treatment to increase the applicability of the prickly pear cactus fruit extract and possibly other insoluble natural antioxidant compounds in foods by improving their antioxidant activities and solubility in water. </P>

Preservation of red pepper flakes using microwave‐combined cold plasma treatment

Kim, Jung Eun,Oh, Yeong Ji,Song, Ah Young,Min, Sea C John Wiley Sons, Ltd 2019 Journal of the Science of Food and Agriculture Vol.99 No.4

<P><B>Abstract</B></P><P><B>BACKGROUND</B></P><P>Red pepper flakes are often contaminated with various microorganisms; however, any technologies aiming to decontaminate the flakes should also maintain their quality properties. This study investigated the effect of microwave‐combined cold plasma treatment (MCPT) at different microwave power densities on microbial inactivation and preservation of red pepper flakes. Red pepper flake samples inoculated with spores of <I>Bacillus cereus</I> or <I>Aspergillus flavus</I> and without inoculation were subjected to MCPT at 900 W for 20 min at either low microwave power density (LMCPT, 0.17 W m<SUP>−2</SUP>) or high microwave power density (HMCPT, 0.25 W m<SUP>−2</SUP>).</P><P><B>RESULTS</B></P><P>The numbers of <I>B. cereus</I> and <I>A. flavus</I> spores on red pepper flakes after LMCPT and HMCPT were initially reduced by 0.7 ± 0.1 and 1.4 ± 0.3 log spores cm<SUP>−2</SUP> and by 1.5 ± 0.3 and 1.5 ± 0.2 log spores cm<SUP>−2</SUP> respectively and remained constant for 150 days at 25 °C. Immediately after HMCPT, the concentrations of capsaicin and ascorbic acid in the flakes were significantly lower than in untreated samples; however, no difference in concentration was detected during storage. Neither LMCPT nor HMCPT affected the antioxidant activity or color of the flakes during storage. LMCPT also did not affect the sensory properties and the concentrations of capsaicin and dihydrocapsaicin of the flakes, indicating its suitability in preserving their quality properties.</P><P><B>CONCLUSION</B></P><P>MCPT may provide an effective non‐thermal treatment for food preservation which can improve the microbial safety and stability of red pepper flakes while maintaining intact their qualitative properties. © 2018 Society of Chemical Industry</P>

Malic Acid를 사용한 탈지 대두박 기반 항균 가식성 필름 개발

김정은,이한나,송아영,민세철 서울여자대학교 자연과학연구소 2013 자연과학연구논문집 Vol.25 No.-

Formation of edible films from food-process by-products, defatted soy bean meal (DSM), soybean meal-extracted soy protein, and persimmon peel and whey protein, has been investigated. The DSM-based film had a higher tensile strength (TS) (4-12 MPa) and percentage elongation at break (%E) (2.5-16.0%) than the films made of soybean meal-extracted soy protein or persimmon peel and whey protein, and the DSM-based film was selected as the base film material for developing an antimicrobial edible film incorporating malic acid. The malic acid-incorporating DSM-based film (MA-DSM film) inhibited Salmonella Typhimurium (2.2, 3.2, and 4.2 log CFU/cm2). The inhibition increased with the increase of the concentration of malic acid in the film from 10 to 30% (w/w, dry basis). The addition of malic acid increased lightness and %E (stretchability) and decreased TS (strongness) and Young’s modulus (stiffness) of the MA-DSM film. However, the water vapor permeability did not change after the addition of malic acid, indicating the moisture barrier property of the DSM-based film was not affected by the incorporation of malic acid in the film matrix. The results demonstrated the potential of applying MA-DSM films to food products and control surface contamination of the products with respect to Salmonella.

In-package inhibition of <i>E. coli</i> O157:H7 on bulk Romaine lettuce using cold plasma

Min, Sea C.,Roh, Si Hyeon,Niemira, Brendan A.,Boyd, Glenn,Sites, Joseph E.,Uknalis, Joseph,Fan, Xuetong Elsevier 2017 Food microbiology Vol.65 No.-

<P><B>Abstract</B></P> <P>Dielectric barrier discharge atmospheric cold plasma (DACP) treatment was evaluated for the inactivation of <I>Escherichia coli</I> 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 <I>E. coli</I> 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 (<I>P</I> > 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 <I>E. coli</I> 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.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Dielectric barrier atmospheric cold plasma (DACP) was applied to <I>E. coli</I> O157:H7. </LI> <LI> DACP inhibited <I>E. coli</I> O157:H7 on bulk lettuce layered in a commercial container. </LI> <LI> DACP uniformly inhibited the pathogen on 3- and 5-layer cut lettuce. </LI> <LI> Shaking container ensured inhibition uniformity in the 7-layer lettuce sample. </LI> <LI> Sensory and metabolic properties of the bulk lettuce were unaffected by DACP. </LI> </UL> </P>

Absorption of d-Limonene in Orange Juice into a Laminated Food Package Studied with a Solid Phase Micro-extraction Method

Hahn-Bit Lee,Hee-Jae Yang,Sea C. Min 한국산업식품공학회 2010 산업 식품공학 Vol.14 No.4

The methods for determining the diffusion parameters for the diffusion of d-limonene, a major volatile compound of orange juice, through a multi-layered food packaging material and predicting its absorption into the packaging material have been investigated. The packaging material used was the 1.5-mm thick multi-layered packaging material composed of high impact polystyrene (HIPS), polyvinylidene chloride (PVDC), and low density polyethylene (LDPE). Orange juice was placed in a cell where volatiles were absorbed in the sample package and kept at 23±2oC for 72 hr. The d-limonene absorbed in a 1.5-mm thick multi-layered food packaging material was analyzed by a solid phase micro-extraction (SPME). The absorption parameters for the absorption of d-limonene in the packaging material were determined and absorption of d-limonene into the packaging material was predicted using absorption storage data. The SPME desorption at 60oC for 1 hr resulted in the most sensitive and reproducible results. The diffusion coefficients of d-limonene in the packaging material and the partition coefficient at 23±2oC were approximately 1-2×10-12m2/s and 0.03, respectively. The absorption profile no earlier than 30 hr was fit well by a model derived from the Fick’s law.

Pasteurization of mixed mandarin and Hallabong tangor juice using pulsed electric field processing combined with heat

Lee, Seung Jo,Bang, In Hee,Choi, Hyuk-Joon,Min, Sea C. 한국식품과학회 2018 Food Science and Biotechnology Vol.27 No.3

Effects of pulsed electric filed (PEF) processing combined with heating (H-PEF processing) on the inactivation of microorganisms and the physicochemical properties of mixed mandarin and Hallabong tangor (MH) juice were studied. Using a pilot-scale PEF system, MH juice, pre-heated at $55^{\circ}C$, was PEF-treated at 19 kV/cm of electric field and 170 kJ/L of specific energy and the juice, pre-heated at $70^{\circ}C$, was PEF-treated at 16 kV/cm and 100 kJ/L or 12 kV/cm and 150 kJ/L. H-PEF processing at $70^{\circ}C$-16 kV/cm-100 kJ/L reduced the aerobe, yeast/mold, and coliform counts of MH juice by 3.9, 4.3, and 0.8 log CFU/mL, respectively, without affecting the ascorbic acid concentration and antioxidant capacity of juice. H-PEF processing changed juice color and browning degree (p < 0.05), but not total soluble solid content or pH. By controlling initial juice temperature and electric field strength, H-PEF processing can be an effective pasteurization method for mixed juice with minimal changes in quality.

Development of Strawberry-based Jelly as a Universal Design Food in Terms of Hardness

Ji Hyeon Kim,Hyeon Ju Lee,Myung Hwan Kim,Gwi Jung Han,Sea C. Min 한국산업식품공학회 2016 학술대회 및 심포지엄 Vol.2016 No.10

Strawberry jelly as a universal design food was developed using strawberry juice (SJ), sugar, xanthan gum (XG), and locust bean gum (LBG). Experimental variables included SJ concentration (30-40% (w/w)), sugar concentration (7.5-10.0% (w/w)), and the ratio of XG/LBG (0.3-4.0% (w/w)), and response variables were textural (hardness, gumminess, chewiness) and color properties. The formulation of strawberry jelly was optimized against hardness and the interactions among variables were predicted using the response surface methodology. Controlled storage test at 5 or 15°C was conducted to determine the values of the jelly at different temperatures. The optimal SJ and sugar concentrations and the ratio of XG/LBG against hardness were 40, 10, and 1.5%, respectively. The color did not change significantly during storage at 5 and 15°C (p>0.05). However, the textural characteristics during storage increased significantly at 5°C (p<0.05) and the hardness was appropriate to be used as a criterion for determining the shelf life of the jelly. The shelf life at 5°C generated from a zero-order kinetics (R²=0.96) was 40 d according to a criterial value, 1.8 N, of hardness. The Q10 value was calculated as 0.6, which allowed prediction of the shelf life values at different temperatures. The results from this study suggested a formulation of strawberry jelly as a universal design food and allowed determination of the shelf life of the food product.

비열 플라즈마 처리를 이용한 채소와 향신료의 미생물 저감화

김정은(Jung Eun Kim),김인하(In-Hah Kim),민세철(Sea C. Min) 한국식품과학회 2013 한국식품과학회지 Vol.45 No.6

본 연구에 사용된 비열 플라즈마 처리는 양배추와 상추에 접종된 S. Typhimurium, 후춧가루에 존재하는 호기성 미생물, 그리고 고춧가루에 접종된 B. cereus 영양 세포를 효과적으로 저해시켰으나, 고춧가루에 존재하는 호기성균과 B. cereus 포자는 효과적으로 저해시키지 못했다. 양배추에 접종된 S. Typhimurium를 가장 많이 저해시키는 최적 조건은 746 W, 6.8분으로 예측되었고, 이 때 저해 정도는 1.9 log CFU/cm2로 예측되었다. Fermi 모델과 Weibull 모델이 플라즈마 처리를 이용한 양배추에 접종된 S. Typhimurium 저해를 설명하는데 매우 적합하였다. 본 연구의 결과는 비열 플라즈마 처리를 채소류와 분말 식품의 미생물 안전성을 증진시키는 살균 처리 기술로 발전시키는데 유용할 것으로 사료된다. Effects of cold plasma treatment (CPT) against Salmonella Typhimurium inoculated on cabbage and lettuce, naturally occurring bacteria in black pepper powder and red pepper powder, and Bacillus cereus inoculated onto red pepper powder were investigated. The numbers of S. Typhimurium on cabbage and lettuce were reduced by 1.5±0.2 CFU/cm2 (900W, 5 min) and 1.1±0.1 log CFU/cm2 (900W, 10 min), respectively. The numbers of naturally occurring aerobic bacteria in both black pepper powder and red pepper powder were reduced by 2.3±0.3 and 0.6±0.2 log CFU/g, respectively. The numbers of B. cereus vegetative cells on red pepper powder were reduced by 1.5±0.1 log CFU/g, but the numbers of spores remained unchanged. The inhibition of S. Typhimurium on cabbage was adequately described by Fermi’s model and the Weibull model. The predicted optimum treatment power and time for S. Typhimurium inoculated onto cabbage were 746 W and 6.8 min, respectively. Our results indicate that CPT represents a useful method for microbial decontamination of vegetables and spices.