Rachel Burford, Georgina Roberts and a penalty try ramped up the scoreline after the interval but, despite dominating the Italians, Street felt the six-time defending Six Nations champions were guilty of sloppy moments.
Adding to their 47-0 opening day triumph over Scotland, England lie top of the table but Street insists his players must tighten up their game to continue their winning streak against Wales in two weeks' time.
"We're delighted to get another win under our belts," said Street.
"The performance was a mixed bag really. Some of our tries were world class and we showed some real brilliance but we also struggled a bit.
"We tried too hard sometimes with passes going amiss or by making simple mistakes.
"Next up we face Wales at Twickenham in two weeks' time.
"We now have a week to iron out some areas of our game as we know Wales will like nothing better than inflicting a win on us on our home turf."