Disinfection efficiency of chlorine dioxide gas in student cafeterias in Taiwan

Abstract

In Taiwan, the food and drink requirements of students and faculty members are met by student cafeterias. The air quality within these cafeterias should satisfy the guidelines laid down by the Taiwan Environmental Protection Agency (Taiwan EPA). Accordingly, this study performed an experimental investigation into the efficiency of two different gaseous chlorine dioxide (ClO 2 ) treatments in disinfecting a local student cafeteria, namely a single, one-off application and a twice-daily application. In both cases, the ClO 2 was applied using strategically placed aerosol devices. The air quality before and after disinfection was evaluated by measuring the bioaerosol levels of bacteria and fungi. Moreover, a stepwise discriminant analysis method was applied for predicting the residual concentrations of bacteria and fungi, as a function of the environmental parameters and the ClO 2 concentration. The experimental results showed that the average background levels of bacteria and fungi prior to ClO 2 disinfection were 972.5 AE 623.6 and 1534.1 AE 631.8 colony-forming units (CFU)/m 3 , respectively. A single ClO 2 application was found to reduce the bacterial and fungal concentration levels by as much as 65% and 30%, respectively. By contrast, a twice-daily ClO 2 application was found to reduce the bacterial and fungal concentration levels by as much as 74% and 38%, respectively. The statistical analysis results showed that the residual bacterial concentration level was determined primarily by the number of individuals present in the cafeteria, the temperature, and the ClO 2 concentration, whereas the residual fungal concentration level was determined mainly by the temperature, the total number of suspended particles, and the ClO 2 concentration. Thus, the integrated results suggest that the air quality guidelines prescribed by the Taiwan EPA for student cafeteria can best be achieved by applying ClO 2 twice daily using an appropriate deployment of aerosol devices.Implications: ClO 2 gas can destroy all manner of microorganisms, including bacteria, spores, fungi, viruses, and even protozoans, in indoor environments. Moreover, it is popularly known that bioaerosols are able to grow and propagate on a wide variety of building materials and indoor surfaces. Thus, through optimal ClO 2 disinfection methodology, the indoor microbial contaminants can be decreased and the residual concentrations of bacteria and fungi as a function of the environmental parameters and the ClO 2 concentration can be predicted via some statistical techniques.

Use of chlorine dioxide to sterilize medium for tissue culture of potato

“…CD is an environmentally safe disinfectant that does not release toxic substances while sterilizing. CD has been applied broadly, including to disinfect tap water 22 , refresh agri-products 23 and sterilize air 24,25 . In 2009, Cardoso successfully used CD to sterilize plant media to culture anthurium 13 .…”

A study of the properties of chlorine dioxide gas as a fumigant

“…Although gaseous ClO 2 inactivates bacteria, viruses and fungi [ 6 , 8 , 9 , 10 , 23 , 24 , 25 ], its antimicrobial effect is known to be affected by the atmospheric moisture [ 14 , 16 , 17 ]. Therefore, under conditions of high-humidity (75%–85% relative humidity), we evaluated the antibacterial effect of ClO 2 gas against S. aureus , E. coli and B. atrophaeus spores.…”

“…Aqueous ClO 2 is known as an environment-friendly disinfectant and has been successfully employed for the treatment of drinking water [ 3 , 19 , 27 ] because, unlike chlorine, it does not result in the formation of trihalomethanes or react with ammonia to form chloramine in water. Recent studies presented that gaseous ClO 2 also has a potent antimicrobial efficacy [ 6 , 8 , 9 , 10 , 23 , 24 , 25 ]. However, because the generation of ClO 2 typically requires employing an expensive machine, the gas so far has not been widely used as a fumigant.…”

Inactivation of Salmonella on Eggshells by Chlorine Dioxide Gas

“…ClO 2 has been known to be a potent sanitizer/disinfectant for more than 40 years ( Benarde et al ., 1965 ). Recently, ClO 2 in its gaseous form has been used to disinfect space, food, and food-related equipment ( Hsu and Huang, 2013 ; Lee et al ., 2004 ; Lowe et al ., 2013 ; Prodduk et al ., 2014 ; Sun et al ., 2014 ; Trinetta et al ., 2012 ; Trinetta et al ., 2013a ; Trinetta et al ., 2013b ). The use of ClO 2 gas as an effective disinfectant is promising for the microbial reduction on fruits ( Du et al ., 2003 ).…”