Holland America Line has announced that the Amsterdam and Noordam recently earned a perfect score of 100 on United States Public Health (USPH) inspections conducted by the U.S. Centers for Disease Control and Prevention (CDC). The Amsterdam’s and Noordam’s scores are said to follow the sister ship Zuiderdam’s perfect 100 earlier this year, adding to the Eurodam’s record-making six-year run of perfect scores.

According to Holland America, the Amsterdam’s unannounced USPH inspection was held Aug. 9, 2018, during a call at Sitka, in the middle of a seven-day Alaska cruise. The Noordam’s inspection was held Aug. 29 at Juneau, also in the middle of a seven-day cruise. Over the past five years, several Holland America Line ships have achieved a perfect score of 100 nearly 30 times, the cruise line stated.

CDC inspections are part of the Vessel Sanitation Program, which was introduced in the early 1970s and is required for all passenger ships that call at a U.S. port. The inspections are unannounced and are carried out by officials from the United States Public Health Service twice a year for every cruise ship.

The score, on a scale from one to 100, is assigned on the basis of a checklist involving dozens of areas of assessment encompassing hygiene and sanitation of food (from storage to preparation), overall galley cleanliness, water, shipboard personnel and the ship as a whole.