Well, I think Mai Kuraki has only
42 singles out.
Official site discography here
But, every single she's released since her debut with Love, Day After Tomorrow has been in the top 10. Maybe that's what they meant. (Which is kind of amazing. Every single to be in the top 10 since 19-freaking-99. And, you know, not to mention, her
entire career.)
Wikipedia states 'Kuraki holds the record for being the only female artist to have all of her singles consecutively debut in the Top 10 since her debut'
(Sure, wikipedia is definitely not the greatest place to go throwing around facts but it's the best I can do. So she may not have the most consecutive top 10 singles, but her top 10 streak has never ended since she began.)