The outer layer of the epidermis, called the stratum corneum (SC), comprises keratin-rich cells and intercorneal lipids. Staphylococcus aureus has been linked to the fragility of the stratum corneum and formation of atopic dermatitis (AD) lesions. Thus, binding of keratin to bacteria may reflect their binding to the AD-like stratum corneum. In this study, keratin films were prepared using keratin extracted from hair and their potential for bacterial removal and adhesion was investigated using chlorine dioxide, which exhibits bactericidal effects, and fucoidan, which is thought to inhibit bacterial adhesion. The results showed that chlorine dioxide was effective at the removal of S. aureus, whereas fucoidan effectively inhibited bacterial adhesion. Therefore, keratin films can be used to evaluate bacterial removal and inhibition of bacterial adhesion, and the results of this evaluation may reflect those of the AD-like stratum corneum. Using these methods, the effects of fucoidan on indigenous skin bacteria (Staphylococcus epidermidis and Cutibacterium acnes) and general bacteria (Escherichia coli) involved in moisturization were investigated. The results showed that fucoidan inhibited adhesion of S. epidermidis and S. aureus, but did not remove bacteria. Overall, the fucoidan (1700 kDa) used in this study has the potential to prevent and treat AD by inhibiting S. aureus adhesion and improving moisturization by maintaining C. acnes.