From the Guidelines
Oatmeal soap does not inherently promote bacterial growth, but improper storage or preparation can lead to contamination. When considering the use of oatmeal soap, it's essential to understand that the soap itself, whether commercial or homemade, is not typically a medium for bacterial growth due to its low moisture content and the presence of preservatives in commercial products 1. However, the key factor influencing bacterial growth is not the oatmeal soap's composition but rather how it is stored and used.
- Proper storage in a dry, well-ventilated area is crucial to prevent moisture accumulation, which can lead to bacterial growth.
- Homemade oatmeal soap, in particular, requires careful preparation to ensure it is properly cured, reducing its moisture content and thereby minimizing the risk of bacterial contamination 1.
- It's also worth noting that while oatmeal soap may not promote bacterial growth, handwashing with plain soap (which could include oatmeal soap without antimicrobial additives) can remove loosely adherent transient flora from the skin, but it may not remove all pathogens 1.
- Furthermore, the addition of emollients to soap preparations, like those found in some oatmeal soaps, can reduce skin irritation and dryness associated with soap use 1.
- In rare cases, contamination of soap can occur, but this is more related to the handling and storage of the soap rather than its composition 1.
- To ensure the safe use of oatmeal soap, it's recommended to store it in a way that allows it to dry between uses and to discard any soap that shows signs of spoilage or contamination.
From the Research
Oatmeal Soap and Bacterial Growth
- Oatmeal soap, specifically colloidal oatmeal, has been studied for its effects on skin health and microbial communities.
- According to a study published in 2021 2, colloidal oatmeal was found to support the growth of cutaneous commensal bacteria, including Staphylococcus epidermidis, and enhance the production of lactic acid.
- This suggests that oatmeal soap may promote the growth of certain beneficial bacteria on the skin.
Skin Microbial Communities
- A study published in 2018 3 investigated the effect of antibacterial soap on skin microbial communities in a rural Malagasy population.
- The results showed that soap use did not significantly impact ecological measures of diversity and richness, but the amount of soap used was a predictor of community-level change.
- However, this study did not specifically examine oatmeal soap, but rather antibacterial soap.
Bacterial Transfer from Soap
- A study published in 1988 4 found that washing with contaminated bar soap is unlikely to transfer bacteria to the hands.
- Another study published in 1984 5 compared the microbial flora of in-use soap products and found that bar soaps had a higher bacterial load than liquid soaps.
- However, these studies did not specifically examine oatmeal soap, but rather general soap products.
Colloidal Oatmeal and Skin Health
- A study published in 2016 6 found that colloidal oatmeal improved skin barrier function and provided clinically effective benefits for dry and compromised skin.
- This suggests that oatmeal soap, which often contains colloidal oatmeal, may have beneficial effects on skin health, but the specific relationship between oatmeal soap and bacterial growth is still being researched.