Article Figures & Data
Figures
- FIG 1
N95 respirator microwave steam decontamination by ceramic mug either inside or in the absence of Ziploc containment. (A) Image of ceramic mug decontamination system. A 10-cm-diameter mug was filled with 60 ml of distilled water and covered with mesh from a produce bag, secured with a rubber band. Triplicate N95 1-cm2 coupons were placed on top of the mesh. The mug was then placed in the microwave either in a sealed, ventilated Ziploc bag or directly into the microwave. (B) After a 1-min microwave treatment, with or without Ziploc bag enclosure, or a 60-min treatment with dry 105°C heat, phage was extracted from N95 coupons and quantified by plaque assay. Triplicate untreated N95 coupons were included as controls in all assays. There was no significant reduction in plaque titer between Ziploc bag-enclosed and open-mug decontamination systems or between dry-heat-treated and untreated controls (P = 0.9 or P = 0.66, respectively, as determined by analysis of variance (ANOVA) with Holm Sidak posthoc test). PFU, plaque-forming units, a direct measure of viable viral titer; n.s., not significant.
- FIG 2
N95 respirator decontamination by microwave-generated steam over an open ceramic mug. (A) Triplicate N95 coupons treated with 107 PFU MS2 were placed on the mesh-covered ceramic mug and treated for the indicated durations in an 1,100-W microwave. After treatment, phage was extracted from N95 coupons and quantified by plaque assay. (B) We next evaluated treatment of an entire N95 respirator on the mug decontamination system. (C) 107 PFU of MS2 was spotted on 10 premarked sections of a whole N95 respirator as indicated. (D) After a 3-min treatment in an 1,100-W microwave, demarcated pretreated segments measuring 1 cm2 were excised from the respirator, and MS2 phage was then extracted and quantified by plaque assay. Triplicate untreated precut N95 coupons were included as a control in all assays. Bars shown are means and standard deviations of phage titers from each excised segment from a single respirator. An asterisk indicates that no viable MS2 were detected. The limit of detection of all assays is 10 PFU. Data shown are representative of three separate respirator experiments.
- FIG 3
N95 respirator decontamination with microwave-generated steam over an open glass container. (A and B) Image of glass container decontamination system. A 17 cm × 17 cm glass container was filled with 60 ml of distilled water, covered with mesh from a produce bag, secured with a rubber band. (C) Triplicate N95 respirator coupons inoculated with 107 PFU MS2 phage, placed on the mesh-covered container, and treated for indicated times in an 1,100-W microwave. After treatment, MS2 phage was extracted from N95 coupons and quantified by plaque assay. (D) 107 PFU of MS2 phage was spotted onto 10 different premarked locations on a N95 respirator as indicated. (E) The whole N95 respirator was then treated for 3 min as shown in panel B in an 1,100-W microwave. Demarcated segments measuring 1 cm2 encompassing the area of inoculation were excised from the respirator, and MS2 phage was extracted and quantified by plaque assay. Triplicate untreated precut N95 coupons were included as a control in all assays. Data shown are the means and standard deviations of plaque titers from a single respirator and are representative of three separate experiments. In one experiment, no viable PFU were detected from all excised segments (data not shown). An asterisk indicates that no viable MS2 was detected. The limit of detection of all assays is 10 PFU.
