I worked for a major meat packing plant and they added dry ice pellets when they ground beef to kee it cool. this practice is approved by the USDA. It is safe for human consumption.

I am a former USDA Compliance Officer and you should contact your local health department for guidance. You cannot sell your brats to restaurants or retail stores only end users under USDA regulations

To sell meat or poultry products at a farmers market the meat must be from inspected sources then you must follow county or state guidelines and sell directly to end users or consumers.

Missouri is one of the 27 States that have their own state inspection program this means they can only sell product produced within their state if they want to sell it across state lines federal inspection is required.