• The Korean Journal of Food And Nutrition
• /
• v.33 no.6
• /
• pp.702-709
• /
• 2020

The purpose of this study was to evaluate microbiological contamination of knives and cutting boards in child-care centers. Materials used in this study were swabbed of cutting boards and knives (blade, handle of knife, and joint of handle and blade) in 129 child-care centers. Mean values of total aerobic bacteria of swabs of knives and cutting boards were 1.7±0.7 log cfu/100 ㎠ and 1.7±0.9 log cfu/100 ㎠, respectively. Contamination levels of coliform bacteria from knives and cutting boards were 1.5±0.6 log cfu/100 ㎠ and 1.7±0.8 log cfu/100 ㎠, respectively. Comparing microbiological contamination levels of knives and cutting boards according to type and size of child-care centers, there was no significant difference. Bacillus cereus was detected in knife handles and cutting boards. Diarrhea-type toxin gene (entFM) was detected in B. cereus isolates. Antibiotic resistance tests showed that B. cereus was resistant to β-lactam antibiotics. To reduce microbiological contamination levels of knives and cutting boards in child-care centers and prevent food poisoning from bacteria contamination, continuous education by children's food-service management center is needed for sterilization and disinfection of knives and cutting boards.

• 제어로봇시스템학회:학술대회논문집
• /
• 1995.10a
• /
• pp.323-327
• /
• 1995

A new air knife system for coating thickness control in hot dip galvanizing process had been developed and installed on the CGL in Pohang Steel Works, POSCO. This new system consists of air knives with remotely adjustable nozzle slot and an automatic control system which can control both longitudinal and traverse coating deviations. Based on the optimal control algorithm, a traverse coating deviation control was designed. The controller controls the lip profile of the air knives with flexible structure according to the deviation of coating weight. From the measured values which are dependent on the strip width, the lip gaps are calculated with optimal algorithm and the model of the coating deviation. Time delay between knives and a coating thickness gauge is solved by the Smith Predictor.

• Journal of Biosystems Engineering
• /
• v.20 no.1
• /
• pp.13-21
• /
• 1995

This study was conducted to investigate the cutting mechanism of reciprocating knife of combine harvester. The cutting operation of reciprocating knife with the arrangement of the low-cutting and the double-cutting was demonstrated through cutting pattern diagram which was drawn by computer graphics. Various kinds and dimensions of reciprocating knives were analyzed using the developed program. The results are summarized as follows (1) The low-cutting type reciprocating knife was represented similar cutting characteristics to the standard type, but the maximum stalk-deflection was decreased as 1/2 level of the standard type. And the first ledger plate should be designed shorter than the second ledger plate. (2) The bunching area and the maximum stalk-deflection for the double cutting knife almost were not changed since cutting velocity ratio of 0.6, but the secondary cut were occurred at ratio of 0.8 and increased rapidly over these ratio. (3) The double cutting knife was recommended for the high speed combine, because its bunching area and the maximum stalk-deflection were decreased as 1/2 level of the standard type. (4) In order to maintain the proper cutting mechanism characterized by the bunching area, the maximum stalk-deflection and the secondary cutting length etc., the adequate cutting velocity at forward speed of 0.5㎧ to 1.2㎧ was from 0.3㎧ to 0.96㎧ for the double cutting knives.

• Journal of forensic and investigative science
• /
• v.1 no.2
• /
• pp.31-43
• /
• 2006

I searched the recent murder cases for other criminal methods of homicides the monthly statistics of the local police agencies of the whole country, I found that there are many criminal cases where knives were used. Based on this finding, I decided to conduct my survey about kitchen knives. The statistics indicated more than five hundread male and female adults were reported to have committed murders. Of the 500 people, 21 used a kitchen knife to commit murder. This study showed that when people have a conflict, the kitchen knife is as a tool that can be easily changed into a weapon. If the points of the knife is round, more homicides could be avoided. If regulations were established, as we have with dagger when producing, selling or purchasing, I would assume that the number of the crimes with knives will be remarkably diminished. It is our responsibility to create a bill concerning regulatory standards in understanding the dangers of kitchen knives. We must immediately participate in active publicity campaigns.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 1997.04a
• /
• pp.506-512
• /
• 1997

Ultrasonic knives have been successfully used for the surgery of many medical fields. However, the conventional ultrasonic knives for surgical operation cannot be controlled its resonant frequency. So if the material to cut has different characteristic impedance then different ultrasonic knife will be needed. Because the optimum driving frequency of ultrasonic knife is different by characteristic impedance of material. In this work, using a frequency variable ultrasonic transducer made of multi-layered PZT vibrator, a frequency controllable ultrasonic knife will be suggested. The design and computation principles will be also derived. For this work, firstly, the characteristics of this ultrasonic knife will be analyzed by transmission line model equivalent circuit, and the free admittance characteristics and vibrational velocity distributions will be obtained. Secondly, we will design and make the frequency controllable electrical oscillator for driving this ultrasonic knife.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.39 no.11
• /
• pp.1719-1723
• /
• 2010

The purpose of this study was to verify feasibility of using a ATP Luminometer, real-time hygiene monitoring tool for food contact surfaces in foodservices. For this, 54 cutting boards, 70 knives, 21 rubber gloves in 4 institutional foodservices were studied. ATP (RLU: relatively light unit) values by ATP Luminometer were compared with APC (CFU: colony forming unit) of swabbing culture method using aerobic count plates of 3M petrifilm. ATP ranged from 0 RLU/$cm^2$ to 64693 RLU/$cm^2$ on knives, from 0.1 RLU/$cm^2$ to 6743.6 RLU/$cm^2$ on cutting boards and from 31 RLU/$cm^2$ to 465635 RLU/$cm^2$ on the rubber gloves. APC ranged from 0 CFU/$cm^2$ to 166667 CFU/$cm^2$ on knives, from 0 CFU/$cm^2$ to 1000 CFU/$cm^2$ on cutting boards and from 0 CFU/$cm^2$ to 730000 CFU/$cm^2$ on the rubber gloves. To express the degree of association between ATP and APC, a linear regression was performed. There were significant positive correlations found between log RLU and log CFU on the knives (r=0.84, p<0.001), the cutting boards (r=0.79, p<0.001), the rubber gloves (r=0.78, p<0.001). Results of this study showed the possibility that ATP bioluminescence technique can be used as the monitoring tool for surface hygiene in foodservices.

• Korean Journal of Health Education and Promotion
• /
• v.23 no.3
• /
• pp.53-63
• /
• 2006

Objectives: The purpose of this study was to analyze the effects of microbe inspections on the hygienic improvement of school food service systems. Methods: Thirty-three school food service systems in Incheon metropolitan city participated in the study from Sep. 2004 to Apr. 2005. Major items of microbe inspections were cutting boards, knives, kitchen towels, and kitchen staff's hands. The Rodac plate and hand plate were used to measure the surface contamination level of germs such as Staphylococcus aureus, Vibrio species, Salmonella species and E. coli. Results: This study compared the results of the inspections in Sep. 2004 and Apr. 2005. The surface contamination level of Staphylococcus aureus and Vibrio species on the knives and kitchen towels had significantly improved. However, the surface contamination level of E. coli on the hands of the kitchen staff had worsened. Conclusions: This study showed that microbe inspections could control the hygienic level of the school food service systems. In the future, microbe inspections should be actively used to improve sanitary conditions in the school lunch system.

• Korean journal of food and cookery science
• /
• v.19 no.2
• /
• pp.231-240
• /
• 2003

The purpose of this study was to evaluate the effect of implementing the HACCP system on foodservice establishments. At first, the hygienic conditions were measured by microbiological hazard analyses of the cooking utensils and working areas. In order to solve the detected problems, the HACCP system was implemented, after what was considered a sufficient settlement period following the initial assessment, then microbiological verification was performed again. In relation to the cooking utensils and equipment(kitchen knives, cutting boards, knives for shredding vegetables, refrigerators, baskets, barts, working tables, preparation tables, tungs, dish-clothes and drains) the microbiological inspection on the Total Plate Count, Coliforms, Staphylococcus aureus and Listeria monocytogenes, were conducted with regard to the working areas(working tables, preparation tables, seasoning's shelves, serving tables, drinking water tables, refrigerators, storage rooms and dining tables), the Total Plate Count and Fungi were also examined. According to the microbiological hazard analyses there were many problems, especially with cutting boards, baskets, barts, dish-clothes and sinkballs. However, by introducing the HACCP system, the microbiological hazard levels were able to be controlled and lowered, and the total aerial bacteria in the working areas of the foodservice establishments were detected at levels below 6 CFU/plate.

• Journal of Environmental Health Sciences
• /
• v.40 no.2
• /
• pp.88-97
• /
• 2014

Objectives: The aim of this study was to evaluate the occurrence of microbiological contamination of kitchen utensils and environments of food service operations at university located in Seoul, Korea. Methods: We collected swab samples from the surfaces of knives, chopping boards, floors, and drains, as well as drinking water and airborne bacteria samples from 20 food service operations. Three bacterial indicators and five food poisoning bacteria were measured quantitatively and qualitatively, respectively. We used selective culture media and the PCR assay targeting 16S rRNA gene for the microbiological analysis. Results: We detected bacterial indicators on knives or chopping boards in eight different food service operations and, three food service operations (I, M, and O) showed more than 3 log colony forming units $(CFU)/100cm^2$ on their knives, significantly higher than the others. The levels of bacterial indicators on the floors and drains in the cooking areas were much higher than those on the cooking utensils. S. aureus was detected on 10 floors and 8 drains. Culturable bacteria were identified in 5 drinking water samples, and food service operation B ($431.1CFU/m^3$) and C ($551.2CFU/m^3$) showed more than $400CFU/m^3$ of total airborne bacteria. Conclusions: These results suggest that some of food service operations in this study may require additional investigation to secure the microbial safety of cooking environments. In addition, further actions including hygiene education for employees and proper guidelines to maintain clean cooking environments should be prepared.

• Journal of Industrial Convergence
• /
• v.21 no.2
• /
• pp.93-101
• /
• 2023

In this study, the physical and chemical fiber damage caused by knives, scissors, and chemicals was analyzed and used as technical data to determine the cause of the damage. Using 4 types of knives, 5 types of scissors and 4 types of chemicals(Sulfuric Acid, Hydrochloric Acid, Sodium Hydroxide, Potassium Hydroxide) physical and chemical to Cotton, Wool, Polyester, Rayon, T/C (Polyester 50%, Cotton 50%), T/W (Polyester 50%, Wool 50%) Damages were created and analyzed for damage caused by tools and chemicals. For penetrating damage caused by knives and scissors, 'V' type damage was generally seen when the blade part was penetrated, 'T', 'ㅁ', ''C' type damage was found, and in the case of scissors, 'Y' ' This type of damage was common. Fiber damage caused by chemicals showed various damage such as remanent trace, corrosion, degraded, contracting, and color changes. Physical damage of fibers showed differences in characteristics according to the shape characteristics of tools, and chemical damage showed differences in characteristics according to chemicals and types of fibers.