Unfortunately it isn't that simple. It won't be classified as food-grade since it is not a food-additive. Sanitizing chemicals are regulated by the EPA, not the USDA/FDA. Some chemicals termed "pool" sanitizers are approved, others are not. It is necessary for end users to make a determination based upon the product literature. Don't ask the local pool dealer...CHECK THE DOCUMENTATION.
If it is an approved sanitizer it will say something like "approved for porous or non-porous food preparation surfaces" on the product label or EPA registration documents. An example for Zappit (note that this is not an endorsement, just one example). The emphasis in italics is mine.
https://www.westlake.com/safety_guid...02-14-2014.pdf
Zappit 73
EPA Reg. No. 748-296
FOOD CONTACT-SANITIZATION - SANITIZATION OF NONPOROUS FOOD CONTACT
SURFACES continued
SPRAY/FOG METHOD
Preclean all surfaces after use. Use a 200 ppm available chlorine solution to control bacteria, mold or fungi
and a 600 ppm solution to control bacteriophage. Prepare a 200 ppm sanitizing solution of sufficient size by
thoroughly mixing the product in a ratio of 1 ounce product with 20 gallons of water. Prepare a 600 ppm
solution by thoroughly mixing the product in a ratio of 3ounces product with 20 gallons of water. Use spray or
fogging equipment which can resist hypochlorite solutions. Always empty and rinse spray/fog equipment with
potable water after use. Thoroughly spray or fog all surfaces until wet, allowing excess sanitizer to drain.
Vacate area for at least 2 hours. Prior to using equipment, rinse all surfaces treated with a 600 ppm solution
with a 200 ppm solution.
__________________________________________________ __________________________________
Zappit 73
EPA Reg. No. 748-296
FOOD CONTACT-SANITIZATION - SANITIZATION OF POROUS FOOD CONTACT
SURFACES
It is a violation of Federal law to use this product in a manner inconsistent with its labeling.
RINSE METHOD - Prepare a 600 ppm solution by thoroughly mixing 3 ounces of this product with 20 gallons
of water. Clean surfaces in the normal manner. Rinse all surfaces thoroughly with the 600 ppm solution,
maintaining contact for at least 2 minutes. Prepare a 200 ppm sanitizing solution by thoroughly mixing 1
ounce of this product with 20 gallons of water. Prior to using equipment, rinse all surfaces with a 200 ppm
available chlorine solution. Do not rinse and do not soak equipment overnight.
IMMERSION METHOD - Prepare a 600 ppm solution by thoroughly mixing, in an immersion tank, 3 ounces of
this product with 20 gallons of water. Clean equipment in the normal manner. Prepare a 200 ppm sanitizing
solution by thoroughly mixing 2 ounces of this product with 10 gallons of water. Prior to using, immerse
equipment in the 200 ppm sanitizing solution for at least 2 minutes and allow the sanitizer to drain. Do not
rinse and do not soak equipment overnight.
SPRAY/FOG METHOD - Preclean all surfaces after use. Prepare a 600 ppm available chlorine sanitizing
solution of sufficient size by thoroughly mixing the product in a ratio of 3 ounces product with 20 gallons of
water. Use spray or fogging equipment which can resist hypochlorite solutions. Always empty and rinse
spray/fog equipment with potable water after use. Thoroughly spray or fog all surfaces until wet, allowing
excess sanitizer to drain. Vacate area for at least 2 hours. Prior to using equipment, rinse all surfaces with a
200 ppm available chlorine solution. Prepare a 200 ppm sanitizing solution by thoroughly mixing 0.7 ounce of
this product with 20 gallons of water.