(10:27 a.m. EST) -- Holland America's Eurodam continued its streak of perfect health ratings from the Centers for Disease Control in 2016, receiving a score of 100 for the 10th consecutive time.
Five other Holland America ships -- Westerdam, Veendam, Noordam, Maasdam and on its first time out, Koningsdam-- also earned perfect scores during the year, joining the 31 total vessels that passed the unannounced inspections with no black marks.
The CDC inspects all ships that sail in or out of a U.S. port twice a year. Ships must earn a score of 86 or higher to pass. In 2015, 32 cruise ships received perfect scores.
Celebrity earned the most perfect scores, with six ships receiving 100: Celebrity Reflection, Celebrity Solstice, Celebrity Eclipse, Celebrity Millennium, Celebrity Silhouette and Celebrity Equinox.
Royal Caribbean had four ships with perfect scores, including Grandeur of the Seas, Allure of the Seas, Radiance of the Seas and Freedom of the Seas, as did Princess Cruises, with Emerald Princess, Regal Princess, Royal Princess and Ruby Princess. Carnival Cruises had three - Carnival Elation, Carnival Victory and Carnival Breeze.
Both Norwegian Cruise Line and Disney Cruises had two ships that scored 100: Norwegian Getaway and Norwegian Spirit; and Disney Fantasy and Magic, respectively.
Within the luxury category, Sea Dream II, Crystal Serenity, Oceania's Regatta and Silver Shadow all earned top scores.
Conversely, two cruise ships failed the inspection in 2016: Royal Caribbean's Empress of the Seas and P&O's Oceana.
When a ship receives a grade of 85 or under, it is usually re-inspected within 30 to 45 days, if still sailing in U.S. waters. Unless the violations pose an imminent health risk, the ship is permitted to continue sailing.
Empress of the Seas received a failing score of 80 on June 3, but then received a 97 on its follow-up inspection on July 9. Oceana, which scored 82 on March 1, hasn't been re-inspected.
--By Chris Gray Faust, Senior Editor