I worked in a Food Safety lab, most of our customers were businesses selling food products, but we did have someone that sent us a can of coke every few months

I worked in a Food Safety lab, most of our customers were businesses selling food products, but we did have someone that sent us a can of coke every few months for, I assume, his own piece of mind. The panel of things you can test for is large, but not super cheap. As an interesting aside regarding testing, in addition to food you can also test control points along the manufacturing process. For example, ultra-sensititve tests on sewer output that detect contaminants is a presumptive bad resultfor the material created since your last all-clear and you then identify what broke and what food isn't good. It some cases, for some contaminants at well-chosen control points, this is a much cheaper and just as reliable way of ensuring safe food. Food safety is a huge industry. The teeth are generally only as sharp as the legal framework mandates but the capabilities are there on the testing side.