• Korean Journal of Food Science and Technology
• /
• 제41권4호
• /
• pp.392-398
• /
• 2009

This study identified risk factors of cross-contamination of foodborne pathogens and established a good agricultural practice (GAP) system for an agricultural products processing center (APC) for perilla leaves. All samples were collected before and after a standard work shift at the APC, while perilla leaves were also collected after each step in the APC. In addition, the workers and their surroundings were sampled by swabbing. The total plate count (TPC) and coliform count in the water samples increased significantly (p<0.05) to 3.36 and 1.73 log CFU/mL after work, respectively. However, no Escherichia coli and Listeria monocytogenes were detected. The bacterial populations of the workers and their surroundings did not differ significantly (p${\geq}$0.05) before and after work. However, Staphylococcus aureus (<1.66 log CFU) was detected at a high rate (13-50%) in the basket, packing table, gloves and cloth. Although perilla leaves passed through the washing steps, the TPC and coliform bacterial populations on the final products were higher (p${\geq}$0.05) than those of unwashed perilla leaves, which indicates that the washing system was not functioning properly. Accordingly, a GAP system with a better washing system should be employed at this facility.

• Restorative Dentistry and Endodontics
• /
• 제35권5호
• /
• pp.368-373
• /
• 2010

Objectives: This study investigated the effect of infection control barrier thickness on power density, wavelength, and light diffusion of light curing units. Materials and Methods: Infection control barrier (Cleanwrap) in one-fold, two-fold, four-fold, and eightfold, and a halogen light curing unit (Optilux 360) and a light emitting diode (LED) light curing unit (Elipar FreeLight 2) were used in this study. Power density of light curing units with infection control barriers covering the fiberoptic bundle was measured with a hand held dental radiometer (Cure Rite). Wavelength of light curing units fixed on a custom made optical breadboard was measured with a portable spectroradiometer (CS-1000). Light diffusion of light curing units was photographed with DSLR (Nikon D70s) as above. Results: Power density decreased significantly as the layer thickness of the infection control barrier increased, except the one-fold and two-fold in halogen light curing unit. Especially, when the barrier was four-fold and more in the halogen light curing unit, the decrease of power density was more prominent. The wavelength of light curing units was not affected by the barriers and almost no change was detected in the peak wavelength. Light diffusion of LED light curing unit was not affected by barriers, however, halogen light curing unit showed decrease in light diffusion angle when the barrier was four-fold and statistically different decrease when the barrier was eight-fold (p < 0.05). Conclusions: It could be assumed that the infection control barriers should be used as two-fold rather than one-fold to prevent tearing of the barriers and subsequent cross contamination between the patients.

• Journal of Food Hygiene and Safety
• /
• 제36권5호
• /
• pp.447-453
• /
• 2021

In this study, the effectiveness of physical control technology, a combined light sterilization (LED, UV) and hot water treatment in reducing Aspergillus ochraceus for food production environment was investigated. In brief, 1 mL aliquot of A. ochraceus spore suspension (10^7-8 spore/mL) was inoculated onto stainless steel chips, which was then dried at 37℃, and each was subjected to different physical treatment. Treatments were performed for 0.5, 1, 2, 5, 8, and 11 hours to reduce the strains using a light-emitting diode, but no significant difference was confirmed among the treatments. However, a significant reduction was observed on the chips treated with UV-C exposure and hot water immersion. After being treated solely with 360 kJ/m² of UV-C on stainless steel chip, the fungi were significantly reduced to 1.27 log CFU/cm². Concerning the hot water treatment, the initial inoculum amount of 6.49 log CFU/cm² was entirely killed by immersion in 83℃ water for 5 minutes. Maintaining a high temperature for 5 minutes at the site is difficult. Thus, considering economic feasibility and usability, we attempted to confirm the appropriate A. ochraceus reduction conditions by combining a relatively low temperature of 60℃ and UV rays. With the combined treatments, even in lukewarm water, A. ochraceus decreased significantly through the increases in the immersion time and the amount of UV-C irradiation, and the yield was below the detection limit. Based on these results, if work tools are immersed in 60℃ lukewarm water for 3 minutes and then placed in a UV sterilization device for more than 10 minutes, the possibility of A. ochraceus cross-contamination during work is expected to be reduced.

• Journal of Plant Biotechnology
• /
• 제50권
• /
• pp.155-162
• /
• 2023

Radish (Raphanus sativus L.), a root vegetable grown worldwide, is consumed in several ways. In the cross between parental lines to produce F1 seeds of radish, the problem of low purity may arise because of pollen contamination. Therefore, we aimed to establish conditions for callus induction and regeneration so that in vitro cultured plants could be used for the propagation of stock seeds. The most effective hormone combination containing various concentrations of 2,4-D, TDZ, and kinetin was selected for callus induction using radish hypocotyl, and the induced calli were transferred to two types of hormone media to investigate the optimal conditions for shoot regeneration of the callus. The combination of 1 mg/L 2,4-D + 0.05 mg/L kin was the most effective for callus induction of RA2 and RA10, 1 mg/L 2,4-D + 0.1 mg/L kin + 0.025 mg/L TDZ of RA4, and 1 mg/L 2,4-D + 0.2 mg/L kin of RA30. Shoot regeneration of the RA4 callus occurred in both shoot regeneration media, but the frequency was much higher in the 5H+1B medium (1 mg/L NAA + 0.1 mg/L 2,4-D + 1 mg/L IPA + 0.02 mg/L GA3 + 2 mg/L zeatin + 1 mg/L BA). For the in vitro micropropagation of radish, the conditions selected in this study can assist in the propagation and maintenance of stock seeds to produce F1 seeds.