I work in a microbiology lab. I was making up some plates for growing bacteria. The only difference in plates was that they contained varying concentrations of Silver Nitrate. The media (ie. bacteria food) contained baby formula, milk powder, yeast extract and agar, a polysaccharide made from seaweed. After autoclaving (exposing to 112 C degree heat with high pressure) the different media, one of the plates turned a strong shade of red, maybe with a hint of orange. Only the plate with a relatively high concentration of silver turned red, so I assume the silver had something do with it. It's possible the reaction precipitated some of the silver, because I noticed more growth than I expected on some plates. But results were inconclusive. Can anybody guess what the reaction was? I'm mainly just curious.