Doyle's video comes as , as the workers are known on YouTube.
In the two-minute video, Doyle said: "We thank members of the online community who quickly alerted us and allowed us to take immediate action.
"Although the individuals in question claim it's a hoax, we are taking this incredibly seriously."
Doyle said the store in Conover, North Carolina, where the videos were made, has been shut down and "sanitized from top to bottom".
He said: "There is nothing more sacred than our customers' trust. We are re-examining all of our hiring practices to make sure that people like this don't make it into our stores.
"It is not a surprise that this has caused a lot of damage to our brand."
Doyle ends the video by saying that Domino's will work hard to regain their customers' trust.
The franchise owner of the store at which the videos were made has already filed a criminal complaint against Michael and Kristy, whom he also sacked after being notified of the videos.
The videos, and rubbing a cleaning sponge between his buttocks, were discovered on YouTube by staff at Consumerist.com, a blog run by Consumer Media, the publisher of Consumer Reports.
They called the store as well as alerting Domino's corporate headquarters.