• Title/Summary/Keyword: sterilization of microorganisms

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Quality Changes in Apple Juice Containing Pulp upon Sterilization by Hot Water (열수 살균 조건에 따른 과육 함유 사과주스의 품질 변화)

  • Park, Nan-Young;Kim, Jae-Whoa;Woo, Sang-Cheul;Jeong, Yong-Jin
    • Food Science and Preservation
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    • v.17 no.2
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    • pp.230-235
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    • 2010
  • We investigated the physicochemical quality characteristics of apple juice upon sterilization using hot water, and under various storage conditions. None of sugar content, acidity, or pH differed significantly among various sterilization conditions but chromaticity was considerably reduced in sterilized juice compared with control material. The chromaticity of non-sterilized juice decreased significantly after sterilization compared with material supplemented with vitamin C (0.1%, w/v). Fungi, yeast, and aerobic bacteria were detected in juice sterilized at $65^{\circ}C$ for 10 or 20 min, but no microorganisms were observed in juice sterilized by other procedures. Vitamin C content affected sterilization temperature to a greater extent than sterilization time. When juice was stored at $4^{\circ}C$ or $37^{\circ}C$ for 3 weeks after application of different sterilization conditions, almost no change in acidity, sugar content, or pH was observed, regardless of sterilization mode or storage period. However, chromaticity decreased with longer storage. Vitamin C levels were reduced by higher sterilization temperatures. However, longer storage periods had the greatest effect on reduction of vitamin C levels, which tended toward lower values regardless of differences in sterilization and storage conditions. In sensory evaluation tests, all of taste, color, and overall preference were highest for juice sterilized at $75^{\circ}C$ for 20 min. The ASC value was low at a storage temperature of $4^{\circ}C$ and at high sterilization temperatures, and a long storage period was associated with a greater ASC value. Thus, the quality of apple juice was excellent when juice was hot water-sterilized, with additional vitamin C, at $75^{\circ}C$ for 20 min, followed by storage at $4^{\circ}C$.

The Effects of Edible Coating and Hurdle-Technology on Quality Maintenance and Shelf-Life Extension of Seafood (식용 코팅 및 허들기술이 수산물의 품질 유지와 저장성 연장에 미치는 영향)

  • Baek, Ji Hye;Lee, So-Young;Oh, Se-Wook
    • Journal of Food Hygiene and Safety
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    • v.35 no.3
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    • pp.205-212
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    • 2020
  • Foodborne diseases occur frequently and have various being related to the intake of contaminated foods. Seafood products are susceptible to contamination due to higher water content and microorganisms, which combine to give them a short shelf-life. Various approaches have been applied to overcome this problem. Edible coatings that are also biodegradable and biocompatible have been discussed as one of the applicable solutions. These coatings can actually help to maintain seafood quality by inhibiting the growth of microorganisms and delaying the loss of moisture. This paper presents the effects of various natural bio-polymers, antimicrobial substances and physical sterilization techniques such as gamma irradiation, ultraviolet (UV) sterilization, and light-emitting diode (LED) sterilization on seafood coatings.

Sterilization of Yakju(Rice Wine) Using a Batch-type High Voltage Pulsed Electric Field System (고전장펄스를 이용한 약주의 회분식 살균)

  • Kim, Su-Yeon;Park, Young-Seo;Mok, Chul-Kyoon
    • Korean Journal of Food Science and Technology
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    • v.31 no.5
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    • pp.1247-1253
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    • 1999
  • Yakju(rice wine) was sterilized with high-voltage pulses of short time on a batch pulsed electric field(PEF) system. The initial microbial counts of Yakju were 7.52 X $10^4\;CFU/mL$ for total aerobes, 2.20 X $10^4\;CFU/mL$ for lactic acid bacteria and 7.08 X $10^4\;CFU/mL$ for yeasts. The pH, acidity and electric conductivity of Yakju were 3.36, 0.462% and 1.24 mS/cm, respectively. Yakju was treated with 2-250 of pulses exponential-wave formed electric pulses under the field strength of 12.5-25 kV/cm. The critical strengths of the electrical field for the sterilization of Yakju were 7.5 kV/cm for total aerobes, 8.5 kV/cm for lactic acid bacteria and 6.5 kV/cm for yeasts. Logarithmic survival rates decreased linearly at low pulse number, but curvilinearly at high pulse number. The PEF sterilization kinetics of Yakju could be analysed by In s = In A-k In (n) and the sterilization rate constant increased with electric field strength and the size of target microorganisms. No changed in pH, acidity, and the growth of microorganisms were found in the PEF treated Yakju during the storage for 6 weeks at both $4^{\circ}C$ And $30^{\circ}C$.

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Current status of research on microbial disinfection of food using ultrasound (초음파를 활용한 식품 살균 기술의 연구 현황)

  • Song, Kyung-Mo
    • Food Science and Industry
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    • v.53 no.3
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    • pp.277-283
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    • 2020
  • Microbial disinfection is essential to increase the preservation and safety of food. In general, thermal sterilization technology is most frequently used, but it often causes nutrient denaturation, and deterioration of food quality. Accordingly, non-thermal sterilization using a novel technology is emerging as an alternative technology. Among them, ultrasonic technology produces a disinfection effect by promoting the destruction of microorganisms by cavitation. Ultrasound technology alone has a low effect, so research is being actively conducted to develop an effective technology by applying as a hurdle technology with various other technologies. Ultrasound can be treated with various processes including traditional sterilization methods such as heating, high pressure, and chemical treatment, as well as novel technologies such as ultraviolet irradiation. Ultrasound assisted sterilization technology still remains at the laboratory level, requiring additional research such as the development of equipment for industrial application and establishment of an optimal process.

Quality Changes of Sterilized Soybean Paste during Its Storage (살균 된장의 저장과정 중 품질변화)

  • 오만진;김종생;최성현;이상덕;이규희
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.28 no.5
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    • pp.1069-1075
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    • 1999
  • The sterilization was attempted to improve the quality deterioration of soybean paste during its storage. For this experiment, soybean paste was sterilized at 80oC for 30 minutes and stored during 6 months at 15oC and 30oC, respectively. The total approximate composition contents were moisture 52.5%, crude protein 11.94%, crude fat 2.0%, amino nitrogen 413.3mg%, sodium chloride 11.61% and ash 15.5%. According to the increase of storage period, pH was decreased gradually because of the increase of organic acids by the metabolism of microorganisms and the acid accumulation by acid forming bacteria, but titratable acidity was increased during storage. Amino nitrogen was rapidly increased for the first one or two month storage period and maintained as the same level for the rest of them. Each amino acid contents of soybean paste, which were glutamic acid, tryptophan, proline, arginine, and aspartic acid, had much higher level than others. In color changes sterilized soybean paste(SSP) was much lower than that of raw ones(RSP). Hunter L and b values on the surface of soybean paste were decreased during storage, and the decreasing levels were higher at 30oC than at 15oC. Hunter a value, however, was increased a little in the initial storage, and thereafter it was decreased. Lactic acid bacteria, yeasts, and molds were disappeared completely by the sterilization. However, the bacteria of aerobes and anaerobes were not disappeared by this processing.

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Evaluation of the Quality of Canned Seafood with Added Spice-oil Extract

  • Yoon, Ho Dong;Shulgin, Yu.P.;Lazhentseva, L. Yu;Shulgina, L.V.;Xie, Chengliang;Mok, Jong Soo;Kim, Jeong Gyun
    • Fisheries and Aquatic Sciences
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    • v.18 no.1
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    • pp.7-11
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    • 2015
  • The influence of spice (cinnamon, allspice, black pepper)-oil extract on canned seafood quality was studied. During the processing of canned seafood, the substitution of spice-oil extract for vegetable oil (refined sunflower, corn, soybean and olive oil) resulted in a decrease in the heat resistance of spore microorganisms, making it possible to reduce the duration of sterilization for canned food to 5-10 min at $115^{\circ}C$. This reduction in the sterilization duration of canned seafood with spice-oil extract inhibited residual microflora in the product, thus reducing the deleterious effect of heating on the main food compounds while preserving protein digestibility.

Radical Mist Generator Using a Water Plasma Jet and Its Sterilization Effect

  • Huh, Jin Young;Ma, Suk Hwal;Kim, Kangil;Choi, Eun Ha;Hong, Yong Cheol
    • Proceedings of the Korean Vacuum Society Conference
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    • 2016.02a
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    • pp.175.1-175.1
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    • 2016
  • In recent, tract infections such as atopic dermatitis, allergic rhinitis and a respiratory disease are increasing, giving rise to the atmospheric pollution, inflow of micro-size dust and side effect of humidifier disinfectant. In this context, the environment-friendly technology is required to eliminate airborne pathogens. We propose solution of the previous problems, making use of Radical Mist Generator (RMG). Existing technologies of air purification using a gas discharge produce harmful substances such as ozone, NOx, etc. However, the RMG uses a pure water as a plasma forming material. The RMG sprays the water mist, which contains reactive radicals to sterilize microorganisms. RMG is comprised of a power supply, plasma electrodes and a nozzle. In order to analyze the electrical characteristic and concentrations of reactive radicals, we employ an oscilloscope and a titration method. To test the sterilization effect of RMG, we used E.coli. We confirmed that E.coli was killed over 90%. Eventually, we expect that RMG can be promising tool for a purified system.

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Sterilization Effects of $\gamma-ray$ and Ozone on Microoganisms Contaminated in Angelica keiskei Powde (신선초 분말에 오염시킨 미생물에 대한 감마선과 오존의 살균효과)

  • 권오진;박순연;김광훈;이현자;변명우
    • Journal of Food Hygiene and Safety
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    • v.11 no.3
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    • pp.221-225
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    • 1996
  • For the purpose of improving hygienic quality of health-foods, sterilization effects of ${\gamma}$-ray and ozone on microoganisms associated with food cultured in the media and contaminated in Angelica keiskei powder were investigated. Ozone was immersed in water and sprayed in air, on the concentration of 3 mg liter-1 at an air flow rate of 5 liter min-3. Test strains cultured in the media completely inhibited by ${\gamma}$-ray at irradiation doses of 0.25~2 kGy. In the case of ozone, test bacteria inactivated after treatment of 10~20 minutes, but test mold, Aspergillus flavus was not effective. Strains contaminated in Angelica keiskei powder completely inhibited by ${\gamma}$-ray at irradiation doses of 2.5~7.5 kGy. However, when the powder was sprayed with ozonized air for 10hours, Bacillus subtilis and Staphylococcus aureus among five strains were eliminated.

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Studies on the Kinetics of the Heat Sterilization (가열멸균의 동력학적연구)

  • 우종학
    • YAKHAK HOEJI
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    • v.7 no.2_3
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    • pp.42-50
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    • 1963
  • The destruction rate of microorganisms by heat follows the first order reaction. In this experiments, the calculated sterilization velocity constants of Escherichia Coli are 1.97 * $10^{-2}min^{-1}.(45{\deg}$ C), 9.53 * $10^{-2}min^{-1}.(55{\deg}$ C) and $1.858min^{-1}.(70{\deg}$ C), 2.89 * $10^{-2}min^{-1}.(80{\deg}$ C), 1.32 * $10^{-1}min^{-1}.(90{\deg}$ C), 2.87 * $10^{-1}min^{-1}.(95{\deg}$ C), 7.91 * $10^{-1}min^{-1}.(100{\deg}$ C) and $1.777min^{-1}.(105{\deg}$ C). In the results, the activation energy of E. Coli is 62.0 Cal $mole^{-1}.(45{\deg}-60-{\deg})$, that of B. Subtilis are 17.8 Cal $mole^{-1}(60{\deg}-80{\deg}$ C) and 47.1 Cal $mole^{-1}(90{\deg}-105{\deg}$ C).

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