• Asian-Australasian Journal of Animal Sciences
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• v.15 no.11
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• pp.1646-1652
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• 2002

Si-Raw is a raw cured meat (raw, cured meat fermented with steamed rice) produced by the aboriginal people of Taiwan. In order to prevent food poisoning or intoxication from botulism, new methods of monitoring the production base on hurdle technology were investigated. New methods investigated incorporated citric acid, sodium hypophosphite, Monascus anka mash, plum paste or lactic acid bacteria inoculum added separately to meat with steamed rice and salt to lower the Aw (water activity) and pH values of the products to control the microbial growth. Results showed that anaerobic bacterial counts, lactic acid bacterial counts and aerobic bacterial counts for the products of all treatments were less than $10^6$, $10^5$ and $10^2cfu/g$, respectively. Sodium chloride content of all products was above 5.46%, water activity was below 0.939 and pH value was below 4.27. IMP was lower and ATP and hypoxanthine were higher. ATP concentrations were higher in the samples which contained the anka mash. Result of sensory panel test indicated that most people preferred the products with added sodium hypophosphite. Except for the fact that the content of tryptamine in the sample with Monascus anka mash was higher, the amine concentrations for all treatments were lower than those of other fermented meat products. The amino acid nitrogen content was higher in the product made from raw meat treated with citric acid, but lower in the other products. Neither Clostridium botulinum nor Trichinella spiralis were detected in any of the treatments. The result may indicate that hurdle technology is effective for hygiene and safe producing Si-Raw.

• Korean Journal of Food Science and Technology
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• v.38 no.1
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• pp.35-41
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• 2006

Possible application of hurdle technology extention of shelf-life of fresh-cut apples was investigated by evaluating various hurdle factors known to be effective microbial growth inhibitors and their synergistic effects. Fresh-cut apples treated with chitooligosaccharide or grapefruit seed extract (GSE) showed higher microbial counts than those treated with distilled water during latter half of storage period, and at high concentrations. Citric and malic acids showed similar results, although microbial counts of fresh-cut apples treated with 0.75% or higher concentration of citric acid increased at 4 days of storage at $18^{\circ}C$, indicating malic acid is more effective than all hurdles tested for controlling microbial growth. Using ascorbic acid and calcium chloride as additional hurdles to control browning and softening, minimum and maximum compositions of dipping solution were: 0.25 : 0.5 : 0.25% and 0.75 : 1.0 : 0.75% malic acid: ascorbic acid: calcium chloride, respectively.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.14 no.2
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• pp.65-72
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• 2008

Vinegar and/or sake are often added for preservation hurdle in Korean seasoned beef product, affecting sensory quality. Sous vide packaging formerly developed requires optimization of formulation recipe in these ingredients. Therefore this study looked into the effect of vinegar and sake on the sensory quality attributes by response surface methodology. The addition of vinegar lowered the product pH significantly but sake addition did increase it slightly. Water activity did not change with the addition of these. Ten day storage at $8^{\circ}C$ did not make any significant changes in salt content and water activity. The added vinegar and/or sake in the formulation degraded the hedonic sensory scores of the product. The storage of the product made the degradation effect less pronounced. For the stored product the effect of sake on taste, texture and flavor was greater than that of vinegar. The respective addition of vinegar and sake less 4.0 and 4.5% could maintain the required sensory quality and thus was suggested in this study as their affordable use level for preservation hurdle.

• Journal of Korea Technology Innovation Society
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• v.17 no.3
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• pp.449-466
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• 2014

There have been various researches on the relationship between a company's R&D investment and the outcome from innovation. However, these studies failed to effectively analyze the decision-making process followed by companies in relation to knowledge production. Especially, in analyzing the patent of companies, the Poisson model has been commonly used, but its limitations have been pointed out. In recent years, many studies have adopted negative binomial models, but they still pose limitations in analyzing the selection process. This paper proposed a hurdle negative binomial model to effectively reflect the company's decision embedded within patent information and conduct an empirical analysis on a survey of businesses' activities. In particular, the study analyzed the selection process of companies in determining the number of patents. As a result of estimation, the presence of over-dispersion was identified. In addition, the Wald-test confirmed that setting up of hurdles was valid, and there was a difference between the results of hurdle models and those of general negative binomial settings.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.10
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• pp.76-91
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• 2019

There have been many studies to examine the patterns in innovations reflecting industry-specific characteristics from an evolutionary economics perspective. The purpose of this study is to identify industry-specific differences in product innovation patterns and determinants of innovation performance. For this, Korean manufacturing is classified into high-tech industries and low-tech industries according to technology intensity. It is also pointed out that existing research does not reflect the decision-making process of firms' R&D implementations. In order to solve this problem, this study presents a Heckman sample selection model and a double-hurdle model as alternatives, and analyzes data from 1,637 firms in the 2014 Survey on Technology of SMEs. As a result, it was confirmed that the determinants and patterns of manufacturing in small and medium-size enterprise (SME) product innovation are significantly different between high-tech and low-tech industries. Also, through an extended empirical model, we found that there exist a sample selection bias and a hurdle-like threshold in the decision-making process. In this study, the industry-specific features and patterns of product innovation are examined from a multi-sided perspective, and it is meaningful that the decision-making process for manufacturing SMEs' R&D performance can be better understood.

• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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• 2002.08a
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• pp.171.1-171
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• 2002

• Korean Journal of Microbiology
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• v.47 no.4
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• pp.364-374
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• 2011

Lactobacillus brevis DK25 isolated from Dongchimi was identified by physiological and biochemical tests and 16S rDNA sequence analysis. Bacteriocin of L. brevis DK25 exhibits inhibitory activity against Enterococcus faecalis and Listeria monocytogenes when using agar well diffusion method. Maximal production of bacteriocin was reached in the beginning of the stationary phase, and inhibitory activity declined after the late stationary phase. This result suggested that bacteriocin was produced in a growth-associated manner. Complete inactivation of bacteriocin activity was observed after treatment with protease, but the activity was stable between pH 4-9 and heat resistant (30 min at $100^{\circ}C$). Bacteriocin showed a concentration-dependent antimicrobial activity against L. monocytogenes KCTC 3569. Moreover, the application experiment showed that combination of bacteriocin (320 AU/ml) with potassium benzoate (0.05%) could significantly reduce the counts of L. monocytogenes KCTC 3569 in mayonnaise during storage at 4 or $25^{\circ}C$ for 10 days. Thus, bacteriocin from L. brevis DK25 may be used for hurdle technology by combination with potassium benzoate in order to increase pathogenic bacteria inactivation in food processing and food safety control.

• 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.

• Food Science and Preservation
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• v.21 no.4
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• pp.581-586
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• 2014

With the current consumer trend toward health and wellbeing, the demand for consumption of fresh cut vegetables has been increasing. As a popular vegetable with functional components, sedum (Sedum sarmentosum) is widely used in Korea as a side dish that needs no cooking. In this study, to provide a hurdle technology for postharvest sedum, the effects of combined treatment of 1% acetic acid for washing and $10kJ/m^2$ UV-C irradiation on the microbial growth and quality of sedum were examined. After the treatment, the sedum samples were stored at $10^{\circ}C$ for six days, and the results of their microbial analysis as well as their color, vitamin C content, and antioxidant activity were analyzed. The combined treatment with acetic acid and UV-C irradiation reduced the initial populations of the total aerobic bacteria and the yeast and molds in the sedum by 3.28 and 4.22 log CFU/g, respectively, compared to those in the control. The Hunter L, a, and b values of the sedum did not significantly differ across the treatments. In addition, the vitamin C content and the antioxidant activity decreased significantly during the storage, regardless of the treatment. These results suggest that the combined treatment with 1% acetic acid and $10kJ/m^2$ UV-C irradiation can be useful as a hurdle technology for retaining the microbiological safety and quality of sedum during its storage.

• Korean Journal of Food Science and Technology
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• v.40 no.6
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• pp.712-716
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• 2008

In an effort to evaluate Salmonella food safety using combinations of preservation techniques, its viabilities when exposed to HCl, acetic acid, and the oxidative agents (hydrogen peroxide and butyl hydrogen peroxide), were analyzed using sub-lethal heat-shocked Salmonella Typhimurium at $56^{\circ}C$. 2D gel electrophoresis and MALDI-TOF MS analyses were also conducted to determine the expression and repression of proteins in heat-shocked cells. Heat-shocked S. Typhimurium evidenced a reduction of viable counts by 1-2 log CFU/mL. However, viality of non heat-shocked S. Typhimurium decreased markedly by 5-6 log CFU/mL at a pH 4 in response to acid and oxidative stresses. Sub-lethal heat treatment greatly increased the resistance of S. Typhimurium against acid and oxidant agents. As for 2D gel electrophoresis and protein identification via MALDI-TOF MS, 17 major proteins in non heat-shocked S. Typhimurium were detected, and only 13 proteins among these proteins were detected in heat-shocked S. Typhimurium. The heat shock proteins such as DnaK and small heat shock proteins were included, and may be associated with the resistance of S. typhimurium against exposure to acids and oxidants. Therefore, even though the promising hurdle technology using the combined mild treatments including heat was applied to S. Typhimurium, the proper heat treatment to reduce its crossprotection activity toward the following preservative agents might be considered.