Easy, just avoid any processed food. Eat only fresh meat, fruit, and vegetables. Make your own bread, jams, pickles, etc. Never eat any fast food, anything from a cafe, or anything at a restaurant. Wrap all your work lunches in linen you made yourself from flax you grew yourself. Boom, problem solved, no more toxic chemicals in your food unless they were in the air or groundwater where your fruits and vegetables were grown, harvested, or processed, or your cattle grazed or were slaughtered or packaged.

Why would one color meat, fruit or vegetables? This can create false expectation of their freshness and quality and must be banned. This is much easier solution.

Also coloring cheese should be banned. I always choose cheese without dyes but many people might be not aware that many types of cheese are artificially colored.