The US FDA refers to the Food and Drug Administration, which does not certify most products under its jurisdiction on the market. If what you mean by FDA certification refers to registration and filing in the FDA system, then most products under FDA jurisdiction need to be registered and filed before entering the United States, and a U.S. agent must be designated, such as food, medicine, Medical equipment, cosmetics, radiation electronic products, etc.
FDA food grade testing generally refers to food contact materials. Definition of Food Contact Substances (FCSs): If a substance can be used as a component of food production, packaging, transportation or support materials and does not have any technical impact on the food, then the ingredient can be called Food contact substances.
For food contact materials, the U.S. Food and Drug Administration (FDA) has special requirements for food contact materials. The specific regulations are extremely complex. For example, some food contact materials can be used in the United States without going through FDA approval or notification; some food contact materials are restricted or prohibited; and some food contact materials can only be supplied to certain companies or licensed companies. How you determine whether your product is regulated depends on its chemical makeup. Any ingredient that makes up the product needs to be reviewed in accordance with the corresponding provisions of the following regulations: "United States Code of Federal Regulations", "Federal Register", current "Food Contact Notice", "Approved Use Letter", "Generally Recognized as Safe Notice" 》, "Basic Exemption List", "FDA Enforcement Actions" (for example: import rejection, import alert, warning letter, etc.),