Thermal inactivation of airborne viable Bacillus subtilis spores by short-term exposure in axially heated air flow

Grinshpun, Sergey A.; Adhikari, Atin; Li, Chunlei; Reponen, Tiina; Yermakov, Michael; Schoenitz, Mirko; Dreizin, Edward L.; Trunov, Mikhaylo; Mohan, Sharad

doi:10.1016/j.jaerosci.2010.01.007

Cited by 42 publications

(72 citation statements)

References 24 publications

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“…The experimental facility and test design were described in detail in our earlier paper (Grinshpun et al 2010). The setup was operated inside a class II biosafety cabinet (Model 6TX, Baker Co., Inc., Sanford, ME).…”

Section: Preparation Of Viral Suspension and Experimental Protocolmentioning

confidence: 99%

“…The above definition assumes that all the viruses were exposed to the same air temperature during the same time interval, which is not the case in the presence of gradients of air temperature and velocity-longitudinally (y) and radially (x) (Figure 1). Unlike the confined thermal systems used for sterilizing food and liquids, a continuously heated air flow system cannot, in principle, maintain a single temperature because of continuous energy transfer (Grinshpun et al 2010;Jung et al 2009b). Consequently, an aerosol particle passing through the chamber is exposed to different temperatures along its trajectory.…”

Section: Preparation Of Viral Suspension and Experimental Protocolmentioning

confidence: 99%

“…Consequently, an aerosol particle passing through the chamber is exposed to different temperatures along its trajectory. In an axially heated flow, the radial (cross-sectional) gradient of air temperature is relatively high in a close proximity to the heater; it essentially diminishes as the distance to the heater increases (Grinshpun et al 2010). The virions moving close to the heater are expected to be inactivated much more efficiently than those moving further from the heater and closer to the wall.…”

Section: Preparation Of Viral Suspension and Experimental Protocolmentioning

confidence: 99%

“…In accordance to the approach developed in our earlier study (Grinshpun et al 2010), the characteristic exposure temperature was defined based on the following considerations:…”

Section: Characteristic Exposure Temperature and Conservative Estimatmentioning

confidence: 99%

“…Consequently, these studies involved microorganisms in aqueous media or on solid surfaces. Few investigations on heat-induced microbial inactivation have dealt with aerosolized biological particles-bacterial spores (Grinshpun et al 2010;Mullican et al 1971), vegetative cells (Jung et al 2009a;Lee and Lee 2006), or fungal spores (Jung et al 2009b). To our knowledge, no data are currently available on the inactivation of aerosolized viruses by their exposure to hot air flow.…”

Section: Introductionmentioning

confidence: 99%

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Inactivation of Aerosolized Viruses in Continuous Air Flow with Axial Heating

Grinshpun

Adhikari

et al. 2010

Aerosol Science and Technology

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Thermal inactivation of viruses has been studied in relevance to food sterilization, water purification, and other "non-aerosol" applications, in which heat treatment is applied for a relatively long time. No data are available on the inactivation of airborne viruses exposed to dry heat for a short time, although this is relevant to biodefense and indoor air quality control. In this study, we investigated inactivation of aerosolized MS2 viruses in a continuous air flow chamber with axial heating resulted from exposures during ∼0.1-1 s. For an airborne virion, the characteristic exposure temperature, T e , was defined utilizing the air temperature profiles in the chamber. The tests were conducted at two air flow rates, Q, which allowed for establishing different thermal flow regimes and exposure time intervals. The experimentally determined inactivation factor, IF, was subjected to correction to account for the temperature profiles. At T e up to ∼90• C (Q = 18 L/min) and up to ∼140• C (Q = 36 L/min), the loss of viral infectivity was relatively modest (≤ 10). However, IF increased exponentially as T e rose from ∼90• C to ∼160• C (for 18 L/min) or from ∼140 • C to ∼230• C (for 36 L/min). Under specific thermal exposure conditions (∼170• C and ∼250 • C, respectively), IF exceeded ∼2.4 × 10 4 (∼99.996% infectivity loss)-the maximum quantifiable in this study. The airborne MS2 virions exposed to hot air for <1 s were found to have survived much higher temperatures than those subjected to thermal treatment in liquid for minutes or hours. The findings are significant for establishing limitations of the heat-based bioaerosol control methods.

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Section: Preparation Of Viral Suspension and Experimental Protocolmentioning

confidence: 99%

Section: Preparation Of Viral Suspension and Experimental Protocolmentioning

confidence: 99%

Section: Preparation Of Viral Suspension and Experimental Protocolmentioning

confidence: 99%

“…In accordance to the approach developed in our earlier study (Grinshpun et al 2010), the characteristic exposure temperature was defined based on the following considerations:…”

Section: Characteristic Exposure Temperature and Conservative Estimatmentioning

confidence: 99%