ABSTRACT
To assess the relationship of bacterial and fungal contamination on used surgical masks worn by the hospital personnel and microbial air quality in their working wards. This is a cross-sectional study of 230 used surgical masks collected from 214 hospital personnel, and 215 indoor air samples collected from their working wards to culture for bacterial and fungal counts. This study was carried out at the hospital in Bangkok. Group or genus of isolated bacteria and fungi were preliminarily identified by Grams stain and lacto-phenol cotton blue. Data were analyzed using paired t-test and Pearsons correlation coefficient at the significant level of p<0.050. Means and standard deviation of bacterial and fungal contamination on inside area of the used masks were 47 +/- 56 and 15 +/- 9 cfu/ml/piece, and on outside area were 166 +/- 199 and 34 +/- +/- 18 cfu/ml/piece, respectively, p<0.001. The bacterial and fungal contamination on used masks from hospital personnel working in the male and female medical wards and out-patient department, as well as the bacterial and fungal counts of the indoor air sample collected from the same area were relatively higher than the other wards. The predominant isolated bacteria and fungi contaminated on inside and outside areas of the used masks and air samples were similar [Staphylococcus spp. and Aspergillus spp.; respectively]. For its relationship, results found that bacterial and fungal counts in air samples showed significantly positive correlation with the bacterial contamination load on outside area of the used masks, r=0.16, r=0.018 and r=0.21,p=0.003, respectively. High bacterial contamination on outside area of the used masks was demonstrated, and it showed a significant correlation with microbial air quality of working wards
ABSTRACT
This research was designed to study the efficiency of non-carbonated soft drink color removal by using granular activated carbon (GAC) for coliform bacteria detection by SI medium. The conditions established in the study were to use 6 color tones of non-carbonated soft drinks (red, green, purple, blue, orange and yellow) which were removed by using 3 GAC amounts (100, 200, 300 mg per soft drink 1 mL) at two contact times of color removal, 30 and 60 minutes. The results showed that a higher amount of GAC and the increasing of contact time significantly increased color removal efficiency at p-value \< 0.05, and that, also, the different color tones of soft drinks significantly affected different color removal efficiencies at p-value \< 0.05. The highest color removal efficiency derived from using 300 mg/mL of GAC amount at 60 minutes, but was not the best suitable for every color tone. The best suitable condition of each color tone was selected from the lowest GAC amount and the shortest contact time for the color removal as well as affected the color of SI medium, which was changed to yellow color for a positive result, but was still purple color for a negative result within 24 hours. Using 200 mg/mL of GAC amount at 30 minutes was the best suitable condition for red-green-purple-orange color tones, using 300 mg/mL of GAC amount at 30 minutes was the best suitable condition for yellow color-tone, and using 300 mg/mL of GAC amount at 60 minutes was the best suitable condition for blue color-tone. The validity of coliform bacteria detection by SI medium for these removed-color soft drinks when compared with the standard MPN method were sensitivity value, specificity value and efficiency of test of more than 80%. Thus, GAC can be used to efficiently remove the colors of soft drinks for coliform bacteria detection by SI medium.