Rusticles, Mars and Human Responsibility

I was reading an article on MSNBC.com today about the Titanic,
http://www.msnbc.com/news/955061.asp?0dm=C12NT. Apparently, there are
microbes called rusticles, that consume the iron in the ship. It is
disintegrating much faster then they initially thought. This got me to
thinking. Mars is red, because of an abundance of iron, correct? So
theoretically, we (humans) could introduce a bacteria on Mars that could be
extremely detrimental. OK, I realize this is a far fetched example. I am
sure there is little chance that rusticles (or whatever the scientific name
is) will harm Mars. BUT...What procedures are in place to ensure our human
visitors do not harm other worlds?

BV.