Potassium Sorbate as a Biocide | Evaluation

Potassium Sorbate as a Biocide EvaluationEvaluation of Potassium Sorbate as a Biocide to Reduce Viability of Total Airborne Fungi in a Higher Educational Building of Computer StudiesChin Ming Er1,a *, N. M. Sunar 2,b, Abdul Mutalib Leman2,c, Othman Norzila1,d, Quin Emparan1,e, Umi Kalthsom1,f, Paran Gani1,g, Nurul Azreen Jamal1,h1Department of Water And environmental Engineering (DWEE), Faculty of Civil And Environmental Engineering (FKAAS), University Tun Hussein Onn Malaysia, 86400 Parit Raja, Batu Pahat, Johor, Malaysia2Department of Chemical Engineering Technology, Faculty of Engineering Technology (FTK), Universiti Tun Hussein Onn Malaysia, 86400, Parit Raja, Batu Pahat, Johor, MalaysiaKeywords Indoor Air Quality, tramp curative, bioactive compounds.AbstractIn countries which are humid throughout the year, mold is a common problem that canful occur even on a reckoner keyboard. It is smelly and may damage the computer keyboards. It is caused by fungal spores in the air. It can also affect occupants healthiness. This study is aimed to evaluate the efficiency of potassium sorbate to bring down viability of interior mobile fungus kingdom in a higher(prenominal) educational twist of computer studies of a university located at Southern Peninsular Malaysia. malted milk extract agar (MEA) was incorporated with the biocide and was used for air try of fungus kingdom at 3 different sites of the building including outdoors. The hard-hittingness of the biocide was evaluated by comparing the do by agar against the untreated agar. It was clearly shown that the biocide can effectively reduce the numbers of colony forming units of the mobile kingdom Fungi at all 3 tested sites (70% averagely) on the treated culture media, while the untreated media at all three sites was colonized by kingdom Fungi with different concentration.IntroductionIndoor mobile fungal contamination is a very common issue nowadays. Its presence brings a lot of problems to indoor occup ants, building owners or managers as it affects the indoor air whole step (IAQ) of those infected buildings and it has been associated with unhealthy symptoms including headache, asthma, allergy and irritant effects, respiratory problems, mycoses (fungal diseases) and several other non-specific health problems 1. IAQ is defined as the air quality within an enclosed building that leads to the comfort and healthiness of its occupiers 2. It is a major concern as around people in the developed and developing countries, such as Malaysia, Singapore, Indonesia and others, spent most of their time indoor in either offices, factories, homes or educational buildings.It has been estimated that approximate 10% of people worldwide and 5% of the population in industrial countries consider fungal allergies 3,4. Some fungi such as Aspergillus versicolor and Stachybotrys chartarum are able to produce mycotoxins and spend a penny been associated with sick building syndrome 1 Many animal studies h ave confirmed that mycotoxins are associated with carcinogenic, immune-suppressive, and other properties 5. Fungi release tiny spores that float through the air and land on other locations to reproduce. When they settle on damp surfaces, the spores can form new mold colonies. If these mobile fungal spores or mycotoxins are inhaled into bronchia and alveoli, they will be lysed and the human body thereby exposed to the primordial and secondary metabolites 6. Inhalation exposure has been suggested to cause acute kidney failure, damage of the upper respiratory tract, and central nervous system damage 7. Thus, the existence of these fungi is unacceptable in indoor environment.Fungi can grow anywhere all over a wide-ranging temperature with sufficient nutrients and moisture 8. Therefore, indoor mold problem has considerable existed in yearlong warm and humid countries like Malaysia and other Southeast Asian countries. In preliminary research, airborne fungi growth was found in a hi gh humid room (relative humidity 87%) in a higher educational building of computer studies by and by conventional therapeutic such as detergent-cleaning and changing of the affected ceiling boards 9. It is dangerous since researchers suggested that the chances of transmitting the contaminating microbes through using of computers in a university setting is potentially slap-up due to the enormous usage of computer keyboards that are not routinely sanitized by numerous users daily 10. The study also shows that the conventional remediation is not a long term solution to circumvent the indoor airborne fungal contamination. However, green solutions are needed to reduce the viability of the airborne fungi and thereby the existence of secondary metabolites of fungi in indoor setting in order to secure the quality of t all(prenominal)ing and learning among educators and students in a university building.Lately, a bioactive compound from food industry, potassium sorbate had been shown to be able to control the growth of two fungus species (Chaetomium globosum and Alternaria alternate) isolated from an indoor mobile coating 11. It is suggested to be effective against airborne fungi too. Therefore, this study aimed to evaluate the ability of potassium sorbate as a biocide to render the viability of indoor airborne fungi in a higher educational building of computer studies of a university located at Southern Peninsular Malaysia.Materials and MethodsSelection of Testing Sites. The indoor airborne fungal samples were taken from a new commissioning higher educational building of computer studies of a university in Johor, Malaysia that had been identified of having microbial growth in indoor environment from previous research 9. Three sites were selected by walk through inspection. They were each to represent a microbial-contaminated site (A), relatively mildly-contaminated site (B) and outdoors (O) of the building. The location for outdoor sampling was as close as possible to the outdoor air intake for the primary air handling system for the building 12.Biocide Antifungal Activity. The antifungal occupation of the potassium sorbate as a biocide was evaluated by air sampling with biocide-treated and untreated culture media which takes into account that the concentration of the viable fungi can be represent by colony forming unit (CFU) analysis as the calculation infraCFU/m3 = Number of colonies x 1000 Sampling time (min) x Flow rate (L/min). (1)The airborne fungi samples were stack away using a BioStage single-stage viable cascade impactor (SKC, USA) attached to a SKC QuickTake 30 Sample Pump (SKC, USA) onto Malt Extract Agar (MEA) plates with 0.03% (w/v) biocide at a pay heed rate of 28.3 L/min as per requirement of National Institute of occupational Safety and Health (NIOSH) stated in method NIOSH Manual uninflected Standard Method (NMAM 0800). The impactor was located at the centre of the sampling location at a height of 1.0 to 1.5 meter abo ve the floor. Every sample was obtained over 5 minute periods. The same procedure was carried out with control MEA without biocides. Both kinds of sampling with treated and untreated MEA were done in triplicate at each site on the same day during office hours and in the presence of indoor occupants. The air samplings at different sites were carried out on different week. The samples were analysed for innate airborne fungi count by incubating them at 37C for 5 days and counting of the colony formed was done thereafter.Results and DiscussionsThe viability of total airborne fungi on the biocide-treated MEA was successfully reduced by 76.2% averagely if compared to their viability on control MEA without biocide (Fig. 1). Notably, potassium sorbate showed the best performance at the mildly-contaminated site, which had the lowest total airborne fungi on control MEA, by successfully reducing the viability of total indoor airborne fungi by 84.2% on biocide-treated MEA. Meanwhile, its perfo rmance dropped when the mean concentrations of total airborne fungi on control MEA increase. The percentage of reduction of viability of total airborne fungi at the contaminated site and outdoors of the building are 63.9% and 80.4% respectively. The results argue that potassium sorbate can show the best performance to control total indoor airborne fungi concentrations if it is applied in a clean environment. This is in accordance with the function of potassium sorbate in wine-making industry to prevent a second fermentation through rendering any surviving yeast incompetent of metabolizing and multiplying 13. Hence, it is suggested that this biocide is very suitable to be applied together with and after conventional remediation of indoor fungal contamination periodically.Fig. 1 Comparison of viability of total airborne fungi on biocide-treated and untreated MEA.According to Industry Code of Practice on Indoor Air Quality (ICOP-IAQ 2010) set by Department of Occupational Safety and H ealth Malaysia, the maximum exposure limit of total indoor airborne fungi concentrations is 1000 CFU/m3. Any value of the concentrations of indoor airborne fungi that approaches or over 500 CFU/m3 can be also considered as a possible health hazard. In this study, this number was successfully reduced to below 100 CFU/m3 at two of the three testing sites and below 200 CFU/m3 at the contaminated site. These reductions might be due to high solubility of this biocide in water of growth media to convert to sorbic acid that exhibits potent antifungal properties with assorted mode of action such as genetic changes, alteration of morphological grammatical construction of cell, inhibition of enzymes and cell transport processes 14. All of these after-treatments numbers suggests that potassium sorbate is a proper biocide to maintain the concentrations of total indoor airborne fungi at an acceptable healthy level for human beings.In a higher educational building of computer studies, computers are always shared. Touches of computer parts oddly computer keyboards by students always occur without practicing of hand hygiene. The sweats or dirt on the hands and fingers of students left on the computer parts after they using them. This in turn provides nutrients and breeding sites for airborne fungi that settle on these computer parts. The reduction of the viability of indoor airborne fungi on the biocide-treated media indicates that the airborne fungi are unable to grow on the substrate that are treated with potassium sorbate and thus suggesting that this biocide can be applied on various wall coatings, surfaces of furniture and electrical appliances including these computer parts.In conclusion, the results of this study indicate that potassium sorbate is fit to be applied as a biocide in a higher educational building of computer studies to reduce the viability of indoor airborne fungi. This in turn reduces the amounts of secondary metabolites of fungi such as mycotoxin and fungal spores that can induce sick building syndrome and other unpleasant and uncomfortable feeling of indoor occupants.AcknowledgementThe authors greatly appreciate Universiti Tun Hussein Onn Malaysia (UTHM) and the supporting Fundamental look into Grant Scheme (FRGS) 1479 for facilitating the work and National Institute of Occupational Safety and Health Malaysia (NIOSH) for providing technical assistance.ReferencesKuhn, D. M., Ghannoum, M. A. (2003). Indoor mold, toxigenic fungi, and Stachybotrys chartarum infectious disease perspective. Clinical microbiology reviews, 16(1), 144-172.Yau, Y.H. Chew, B.T. and Saifullah, A.Z.A. (2012) Studies on the indoor air quality of Pharmaceutical Laboratories in Malaysia. International Journal of Sustainable Built Environment 1, 110124.Pasanen, A. L., Lappalainen, S., Pasanen, P. (1996). 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