Figure 2.

Smartphone sampling procedure and contamination measured by using aerobic bacterial counts at each sampling site. (A) A sterile cotton-tipped applicator moistened with tryptic soy broth (TSB) was used to sample the front of the smartphone face, smartphone-case junction, and sides and back of the smartphone case as designated by yellow dashed lines. (B) Swabs from smartphone sampling were plated down the center of a tryptic soy agar plate with 5% sheep blood, and the initial swab inoculum was spread in perpendicular manner by using a 10-µL disposable inoculating loop. (C) The smartphone face was significantly less contaminated than the phone-case junction. Tukey box and whiskers plot; Kruskal–Wallis with Dunn multiple comparison test, P = 0.0046. †, P ≤ 0.01.