The governing body's chief medical officer claims positive testing in football is frequently as a result of recreational drug use
The World Anti-Doping Authority (Wada) revealed earlier this month that footballers across the world produced 250 urine samples which led to further investigation by drugs testers in 2012, but football's governing body has stressed that recreational drug use is often to blame for positive tests.
"I am confident that there is no systematic doping in football. There is no systematic doping culture in football. I am confident of this," Dvorak told the official Fifa website.
"Of course there are individual cases, for sure. We do more than 30.000 sampling procedures every year and we have between 70 to 90 positive cases, most of them for marijuana and cocaine. We also have anabolic steroids, but these are individual cases.
"So there are some cases; that’s why we are doing so many controls with such a stringent protocol. But we don’t have scientific evidence from the statistical analysis – and for me as a scientist I believe in facts and figures, not in speculation. We have no evidence that there is systematic doping."
The issue of doping in football has reared its head once more this week after Fifa provisionally suspended an unnamed Tahiti player for the use of a forbidden substance at this summer's Confederations Cup.