Effective Sterilization Method of the Bacteria-inducing Offensive Odor of Shoes / 대한피부과학회지

BACKGROUND: It is known that the offensive odor of shoes is due to contaminated bacteria. Therefore, the foul odor can be eliminated if these bacteria are sterilized. There is an effective method to sterilize contaminated shoes, which involves vacuum drying evaporate water at a relatively low temperature. This dehydrates the bacteria rapidly, and sterilizes shoes without damage. OBJECTIVE: This study was undertaken to analyse the contaminated bacteria of shoes and to evaluate the bactericidal effect and rapid dehydration by heating and vacuum drying. METHODS: Contaminated bacteria were isolated from the soles and foul odor shoes of 15 volunteers by swab sampling method. Three strains of Staphylococcus (S.) aureus and S. epidermidis were used to find an effective sterilization method. Vacuum drying or wet heating of bacterial suspension was conducted by a vacuum dryer at various temperatures and exposure times. The treated bacteria were rehydrated and were cultured on nutrient agar petri dishes. The viability was expressed as colony forming unit (CFU) of experimental group divided by that of control group. RESULTS: S. aureus was isolated from the soles and shoes of 7 volunteers, and S. epidermidis from 5 volunteers. In 3 volunteers, both S. epidermidis and S. aureus were isolated. When S. epidermidis and S. aureus were dried for one hour by vacuum drying, the viability decreased as temperature increased, however, no sterilization was noted even at 90 degrees C for 8 hours. Moreover, under vacuum drying at 90 degrees C for 15 minutes, viability was reduced by 10%. The number of bacteria was reduced by 90% after 30 minutes of wet heating at 60 degrees C, or 15 minutes wet heating at 65 degrees C. However, sterilization was only accomplished by wet heating at 60 degrees C for one hour. Therefore, wet heating appears to be effective in reducing and sterilizing S. aureus and S. epidermidis, compared to vacuum drying. Sterilization was not obtained by vacuum drying at a moderate temperature. CONCLUSION: These results indicate that wet heating for one hour at 60 degrees C, followed by vacuum drying at a moderate temperature would be an effective way to sterilize contaminated bacteria, dry shoes and inhibit the offensive odor within shoes.

Effect of Rapid Dehydration by Vacuum Drying on Fungal Viability / 대한의진균학회지

BACKGROUND: Tinea pedis and candidiasis of the feet is the most common type of dermatomycosis. Contaminated shoes may play an important role in spread and relapse of tinea pedis and candidiasis of the feet. However there is no effective method to sterilize contaminated shoes. Since vacuum drying can evaporate water in relatively low temperature, it is thought to be able to dehydrate rapidly and to sterilize shoes without damaging them. OBJECTIVE: This study was designed to evaluate the fungicidal effect of rapid dehydration by vacuum drying. METHODS: The suspension of Trichophyton (T.) rubrum, T. mentagrophytes and Candida (C.) albicans was made with distilled water. Vacuum drying or wet heating of the suspension was conducted in the vacuum dryer at various temperature and time. The treated fungi were rehydrated and were cultured on Sabouraud dextrose agar petri dish. The viability was determined as colony forming unit (CFU) of experimental group divided by that of control group. RESULTS: When C. albicans was dried for one hour by vacuum drying, the viability decreased as temperature increased, but no sterilization was noted even at 80degrees C. Under vacuum drying at 50degrees C for one hour, viability decreased below 3% and there was no difference in the viability between one hour of the treatment and more than one hour. In T. rubrum, T. mentagrophytes, C. albicans, the number of fungi was reduced by 90% under the condition of one hour vacuum drying at 50degrees C. Wet heating was more effective than vacuum drying in reducing and sterilizing C. albicans. Sterilization was done under the condition of wet heating of one hour at 50degrees C or wet heating over 30 minutes at 60degrees C. The higher concentration of C. albicans was, the stronger resistance against the heat and dehydration was observed. Combined teatment with wet heating for one hour followed by vacuum drying for one hour at 50degrees C was effective way to sterilize C. albicans. CONCLUSION: These results suggest combined treatment with wet heating and vacuum drying can effectively sterilize shoes without damage and prevent the feet from spread and relapse of tinea pedia and candidiasis of the feet.