Science can never be a 100% surety, that is why new methods and procedures are being introduced all the time.
In the old days, it was a usual verdict that evidence by alibi, fingerprint or witness statement was the norm. DNA as improved the chances of wrongful conviction, but as stated in this report, further improvements are possibly required on the collection and storage stages. We only have to look at the way the Madeleine McCann incident as turned out, and the methods used in collecting and perhaps processing DNA evidence.
Other examples have occurred over past years (Colin Pitchfork evidence!) when DNA samples were changed or wrongfully submitted. This evidence only came to light via a casual conversation in a pub.But as a result of that, and over the years things have improved considerably, and will do further.