@TruptiG, here's a good breakdown of US Code regarding GMP control within a food plant: Fish and Fishery Products Hazards and Controls Guidance Fourth Edition – June 2021 (fda.gov) Ignore the title as linked, the document is titled "ADDENDUM 2: CURRENT GOOD MANUFACTURING PRACTICES (CGMP)" and is a solid breakdown of what the FDA expects from plants following CGMP protocols.
It's rare we'll find plain spoken explanations as to why we should control specific cases. Codes and laws are written broadly with the expectation plants will adopt individual programs to meet the codes. As you read through, if you need to build a case to show your higher management why PPE shouldn't be worn in a bathroom, you can build the explanation by pointing to the following sections:
(b) Cleanliness. All persons working in direct contact with food, food-contact surfaces, and food-packaging materials must conform to hygienic practices while on duty to the extent necessary to protect against allergen crosscontact and against contamination of food. The methods for maintaining cleanliness include:
(1) Wearing outer garments suitable to the operation in a manner that protects against allergen cross-contact and against the contamination of food, food-contact surfaces, or food-packaging materials.
(6) Wearing, where appropriate, in an effective manner, hair nets, headbands, caps, beard covers, or other effective hair restraints.
(9) Taking any other necessary precautions to protect against allergen cross-contact and against contamination of food, food-contact surfaces, or food-packaging materials with microorganisms or foreign substances (including perspiration, hair, cosmetics, tobacco, chemicals, and medicines applied to the skin).
In short, we know restrooms are points of microorganism growth. If the point of PPE is to protect the food from microorganism transmission, logic dictates we should keep PPE out of restrooms. We know the outdoors are a source of microorganism transmission, so the same logic applies there too.