Sealing an envelope with a quick lick is a common habit many people perform without a second thought. However, there are genuine hygienic and chemical reasons why this practice should be avoided. The materials and processes involved in manufacturing and handling envelopes introduce risks that make alternative sealing methods a much wiser choice. Understanding the specific components and contamination pathways reveals the hazards lurking on the adhesive strip.
Biological Contaminants on Envelope Glue
The journey an envelope takes before it reaches your desk makes the adhesive strip a potential repository for foreign matter. Envelopes are handled by numerous factory workers, packaged, shipped, and stored in warehouses that are not always kept in pristine condition. This extensive travel exposes the paper surfaces to dust, dirt, and an accumulation of microorganisms.
The paper and the remoistenable glue act as surfaces where bacteria and other pathogens can settle and remain viable. Although the glue formula may be sterile when initially applied, subsequent handling means the surface is essentially germ-laden. While the risk of contracting a serious illness from a single envelope is low, introducing unknown environmental bacteria directly into the mouth is unnecessary.
Potential Chemical Exposure from Adhesives
The adhesive used on most modern envelopes is designed to be activated by moisture and is often called “gum.” These gums are frequently dextrin-based, derived from food-grade starches like corn or potato, or sometimes from natural compounds like gum Arabic. This composition ensures that accidentally ingesting a small amount of the glue is not overtly harmful to most people.
The primary chemical concern is the potential for allergic reactions, especially since many dextrin glues are corn-based. For individuals with a corn or potato allergy, even the trace amount of starch ingested can trigger a reaction ranging from mild irritation to severe symptoms. Manufacturers also sometimes add non-food-grade chemicals, such as plasticizers, to improve the adhesive’s performance and shelf life.
These additives are often formulated to discourage licking by imparting an unpleasant or bitter taste. Although these trace chemicals are regulated for use in adhesives, they are not intended for consumption. Repeated exposure can lead to mild symptoms like tongue irritation or an inflamed rash, and the risk of an unknown irritant remains a valid reason to avoid direct contact.
Safe Methods for Sealing Mail
Fortunately, there are several simple and safe alternatives that eliminate the need to use saliva to seal correspondence. The most efficient and hygienic method is to use a dedicated moistening device, such as a small office sponge or a cotton swab dipped in clean water. Lightly dabbing the tool along the adhesive strip provides the necessary moisture to activate the glue without any direct oral contact.
A standard PVA (polyvinyl acetate) glue stick can also be used to quickly run a layer of adhesive over the existing gum, creating a strong seal. For those who frequently mail large batches, investing in an envelope moistener with a roller or brush head is the fastest method. Selecting self-sealing or peel-and-stick envelopes bypasses the issue entirely, offering a secure, mess-free, and instantly sealed closure.