25 June 2015
The Port Health Office (PHO) of the Department of Health (DH) today (June 25) had a joint investigation with Cathay Pacific Airways Limited (CX), the Airport Authority Hong Kong (AA) and Hong Kong Aircraft Engineering Company Limited (HAECO) into the possible source of contamination which led to unsatisfactory laboratory testing results of water samples collected from the aircraft of CX.
Upon verification with CX, the PHO noted that, under the routine water surveillance programme of CX, the laboratory testing results of water samples collected from 14 out of 22 aircraft from June 10 to 18 were found unsatisfactory and coliform organisms were detected at a level ranging from less than ten to 90 colony-forming units per 100 millilitres. According to CX, cleansing and disinfection of water tanks of nine of the 14 affected aircraft have been conducted and results of follow-up testing are pending, while the remaining five aircraft will undergo cleansing and disinfection of water tanks when they return to Hong Kong before June 27.
In addition, CX has suspended the use of potable water for the 14 affected aircraft and arranged bottled water onboard while HAECO has conducted cleansing and disinfection for all eleven water tankers. Results of follow-up testing are pending. According to CX, the 14 affected aircraft did not share a common route and potable water was collected in Hong Kong or other airports.
Under the water surveillance programme of CX, water samples are collected from each aircraft every six months while cleansing and disinfection of water tanks are conducted every three months. The 14 affected aircraft were disinfected from April to June 2015 during the routine disinfection programme.
Regarding the airport, the regular inspection programme of the AA ensures the sanitary condition of the three water filling points in the airport. Results of water samples collected from the filling points on June 1, 8 and 15 were normal while the result of another sample collected on June 22 is pending.
As for ground handling companies, HAECO, China Aircraft Services Limited and Pan Asia Pacific Aviation Services Limited currently provide water filling services to aircraft of respective airlines and have protocols in regular cleansing and disinfection of water tankers. The latest investigation findings revealed that four water tankers of HAECO had filled the 14 affected aircraft.
"We have reviewed the overall water collection and filling procedures for aircraft and investigations so far have not identified the source of contamination. During the investigations, the PHO collected five water samples and five environmental swabs from three water filling points, 19 water samples from 19 water tankers and ten water samples from five airlines for testing. Microbiological investigations of the samples are ongoing," a spokesman for the DH said.
The PHO regularly collects water samples from water filling points at the airport, water tankers and airlines for surveillance. Results of the eight water samples collected from the water tankers of HAECO in May and June were normal.
"Coliform bacteria are not a single species of organism. They are a group of closely related, mostly harmless, bacteria which live in soil, water and the gut of animals. Coliform count is a hygienic indicator and a high level of coliform count generally indicates an unsanitary condition," the spokesman explained.
According to CX, Escherichia coli (E. coli) was not detected in the water samples.
"E. coli is one of the species in the coliform group commonly found in the gut of humans and warm-blooded animals and most strains are harmless. Some, however, such as Shiga toxin-producing E. coli (STEC), can produce powerful toxins and cause severe foodborne and waterborne diseases. The most recognised serogroup of STEC is E. coli O157:H7," the spokesman added.
"This incident was detected by a routine water surveillance programme of an airline while investigation and control measures have been implemented to reduce the health risk exposed to travellers and crew members. We will proceed follow-up investigations with airport stakeholders concerned and will closely monitor the situation," the spokesman said.