The practice of moistening an envelope flap with the tongue to seal it frequently prompts questions about hygiene and safety. This action involves ingesting a small amount of adhesive and potentially coming into contact with microbes on the envelope’s surface. Understanding the actual risks associated with both the biological and chemical components of this everyday item can provide clarity.
Examining the Microbial Risk
Envelopes are handled by numerous people and machines during manufacturing, packaging, and distribution, meaning they collect a variety of microorganisms. These surfaces may harbor common, non-pathogenic bacteria, fungi, or dust particles, especially if stored poorly. However, the concentration and viability of dangerous pathogens on a standard envelope are typically very low.
The likelihood of contracting a serious illness from this low-risk exposure is minuscule. Any bacteria transferred from the envelope to the mouth has a limited chance of survival and even less chance of causing systemic infection. The risk of infection from the glue is extremely small. Furthermore, the exposure time is brief, and the surface area contacted is minimal, making microbial contamination a negligible health threat.
Chemical Components in Envelope Adhesives
Modern envelope adhesives are designed to be non-toxic, as manufacturers anticipate contact with skin and saliva. The primary ingredient in most water-activated envelope glue is dextrin, a natural, edible starch derivative. Another common component is gum arabic, a natural gum sourced from the sap of acacia trees. Both are water-soluble polymers used widely in the food industry.
While some manufacturers may include small amounts of non-food grade chemicals to enhance performance, the quantity consumed when licking a single envelope is extremely small. The minute amount of glue ingested is not considered chemically hazardous, though some people may experience minor irritation or an unpleasant taste. A more practical concern is the possibility of an allergic reaction to an adhesive component or the risk of a small paper cut on the tongue, which can allow germs to enter the bloodstream.
Safe Sealing Methods
For those who wish to avoid the minimal risks of microbial contact or chemical ingestion, several non-oral methods are available for sealing envelopes. The simplest alternative involves using a small sponge, cotton swab, or damp cloth to activate the water-soluble adhesive. Lightly moistening the strip with water achieves the same sealing effect without involving your mouth.
A convenient option is to switch to self-sealing or peel-and-seal envelopes, which feature a protective strip removed to expose a permanent adhesive. For high-volume mailing, a specialized desk-top envelope moistener can efficiently dampen the flap. Everyday alternatives like a standard glue stick or clear adhesive tape can also be used to securely close the flap.