I provide the incorrect source in a previous post. The correct part of 21 CFR is 173.315 (washing of fruits...) Part 178 applying to the sanitizing of food contact surfaces.
... so I don't believe the 100ppm limit is based on occupational hazard. It must be based on some sort of risk being in direct contact with food, right?
I wasn't suggesting the EPA guidance you cited limited the usage of PAA based on occupational hazards (strictly beyond the scope of that entity), just making a side comment from personal experience.
As far as regulations and limits:
Part 173.315 states:
Prepared by reacting acetic acid with hydrogen peroxide. Not to exceed 80 ppm in wash water.
Part 180.1196 states:
An exemption from the requirement of a tolerance is established for residues of peroxyacetic acid in or on all food commodities, when such residues result from the use of peroxyacetic acid as an antimicrobial treatment in solutions containing a diluted end use concentration of peroxyacetic acid up to 100 ppm per application on fruits, vegetables, tree nuts, cereal grains, herbs, and spices.
This exemption seems to apply to end-use residual levels, if I'm reading this correctly, when used as a pesticide. Post-harvest wash would fall under part 173.315.
Why the limits? Perhaps industry has determined a 5-log reduction of target organisms is achieved at this level, and the risk(?) to increased levels is unnecessary? It affect flavors or denatures proteins?
I would recommend consulting with your sanitizer mfg. for an answer.
Again as a side-note, I have attached
28 downloads for a biocide processing aid we used in our plant in excess of 100 ppm (usually around 150 ppm) with no consequential issues, and still compliant to regulation.