Martinez did not respond to questions about whether Celebrity or Royal Caribbean had ever done such a lengthy cleaning before.
The plan follows a "no-sail recommendation" from the CDC, which originally wanted four days but settled on three after talks with the company.
Carolyn Spencer Brown, editor-in-chief of cruise review site Cruise Critic, said she thought the cleaning is "highly unusual."
"I've seen worse, but I haven't seen worse in a long time," Spencer Brown said.
"They're doing the right thing to take it out. Maybe they could have taken it out a cruise earlier," Spencer Brown said.
Martinez said in response that Celebrity has been "working closely" with the CDC since the first sailing on which people took sick.
"After the second cruise, both parties agreed that the enhanced sanitizing would take place in port, in between sailings," she said. "The ship's departure was delayed in order to allow additional time to sanitize the ship."
Now, the Mercury is set to depart again Sunday, two days later than scheduled.
Passengers on the cruise will be refunded for two days in the form of an onboard credit, Martinez said, plus a credit for a future cruise equal to 25 percent of their fare paid.
Celebrity is also offering passengers the chance to cancel without a penalty. Those who take the offer will get a full refund and a certificate for a future cruise equal to 15 percent of the fare paid.
"I think this is appropriate and right," Spencer Brown said. "That's decent of them because a lot of cruise lines will just make you go."