but I’m seriously doubting they easily cover all kinds of food AND all types of chemicals and viruses and bacteria,
You are equating several different things. Chemicals, which is what poisons are, are detectable.
Viruses are rarely put in food. Much easier to just sneeze on him.
Bacteria is usually dealt with by just cooking the food and then not letting it set out. While there are a very few bacteria that can not be dealt with that way the easiest way to deal with them would be to hit the food with gamma rays. That would deal with any bacteria.
Might be why he eats his steaks well done.
And is a germaphobe and drinks canned Coke.