The recommended method to avoid touching the glued edge when opening a package is to open the package laterally and completely, (B).
Why is this the best approach?
This will allow you to access the contents of the package without having to touch the glue.
Locate the seal: Identify the sealed edge of the package. This may be a seam, a fold, or a flap.
Start at one end: Begin opening the package from one end of the seal.
Continue opening: Carefully peel back the seal, following the entire length of the package.
Open the package completely: Once you've reached the other end of the seal, the package should be fully opened.
This method allows you to avoid touching the glued edge and prevents any contamination from the adhesive.