There is no "food grade" stainless steel. You can buy plastic spoons that are food grade or "food compliant". FDA kitchen grade refers to 304 18-8 grade. The FDA specifies a chemical composition for stainless steel used in restaurant kitchens and the medical industry. The steel cannot have less than 18% chromium, 8% nickel and not more than .03% sulfur; thus creating the "18-8" designation. * 17.8% chromium will not qualify it to be "304" grade stainless. Also a company that says it will give you a Ceritificate of Compliance but won't show you the chemical analysis of the steel they are using are most likely using an inferior grade stainless.
All reputable companies will show you the grade of steel they use.