Some codes are more rigid than others in their approach to this question. SQF has interesting guidance on this topic. The relevant section for food processing operaitons (Module 11) says:
11.3.3.1 Clothing worn by staff engaged in handling food shall be maintained, stored, laundered and worn so as not to present a contamination risk to products.
11.3.3.2 Staff engaged in high-risk areas shall change into clean clothing or don temporary protective outerwear when entering high-risk areas.
11.3.3.3 Clothing, including shoes shall be clean at the commencement of each shift and maintained in a serviceable condition. Excessively soiled uniforms shall be changed where they present a product contamination risk.
So how to interpret the above? SQF provides a guidance document that says:
“Employees and visitors must wear clean clothing and footwear while in the processing area. Employees and visitors with excessively soiled clothing are not to handle products or packaging materials. In high risk areas, employees must not wear processing uniforms off site. Employees engaged in low risk processes can wear uniforms off site provided they are properly cleaned at the beginning of their work operation.”
Many people in food processing companies may have a bias in favor of change rooms and leaving uniforms at work. The above guidance from SQF appears to provide some leeway in that direction. Auditors bring their own bias to the party. Ultimately you have to perform a risk analysis and be able to justify any decision you make in this regard. Go to www.sqfi.com to view their GFSI bench-marked program for additional details. BRC and other programs can also provide you with GFSI bench-marked guidance on this topic.