Interesting jobI work in a dairy plant, my job at the moment unload all the tankers of raw milk we personally test them for antibiotics and bacteria. Bacteria is a microscope slide test antibiotics is much like the same as a pregnancy test or the covid test . Rubs me the wrong way just trusting a positive cause if we get one on milk state requires us to well get back a step, doesn't matter what it looks like to us we have to put it in a reader and wait a second for the results and print it out.
A positive requires redoing a positive and negative control and double sample of the milk that came up positive, double sample done twice so four more tests on the milk and has to come up both positive or both negative or keep testing. In 18yrs of doing this 99% of the time it was just a bad test strip, have had some positive but it's a rarity. I don't know how much these test strips cost at work compared to the covid test and I know it really doesn't matter the cost when it comes to food safety my company pays for it just think maybe the covid testing lacks some integrity. Test once positive and positive.