Regulations regarding cleaning of plane water cooking equipment?

The World Health Organization does set standards and guidelines, according to the International Health Regulations which are legally binding on the 194 States Parties throughout the world.

Your answer is within 1.3 Roles and responsibilities on page 3 paragraph 5: in sum, compliance redounds to each airline and, while you might hope that urns are dedicated containers that are washed and sanitized separately, airlines don't share that information (and random testing reports are not encouraging).

World Health Organization Guide to Hygiene and Sanitation in Aviation

The airline has full responsibility for the management of water on board the aircraft; proper water system operation and maintenance procedures are essential to ensure that all of the intended potable water on board is safe. Cleaning of the aircraft water tanks at regular intervals is part of the aircraft maintenance process.

Airlines are responsible for the food they serve on board aircraft, whether it is prepared in an airline-owned “flight kitchen” or obtained from an independently owned catering company. The steps involved—including food preparation, transport to the aircraft, storage and, finally, serving on the aircraft—need to be well coordinated in order to avoid contamination.

Routine cleaning and disinfection are also important aspects of aircraft and airport operations. In addition, aircraft disinfection procedures following transport of a suspected case of communicable disease are a particularly difficult issue that needs to be addressed by many stakeholders in a cooperative approach; not all effective disinfectants are suitable for use on board aircraft, as they may cause corrosion or other damage to the aircraft structure and contents, or their fumes may be noxious to inhale in an unventilated space. WHO, IATA, aircraft manufacturers and ICAO are the main organizations involved in determining a suitable disinfection process at the international level.

Box 2.1. Studies on aircraft water safety

Random testing of water on aircraft by Health Canada in June 2006 found that 15.1% of the aircraft tested positive for total coliform bacteria and 1.2% tested positive for E. coli. Most contamination was found in water from lavatory taps or faucets, indicating the possibility of localized contamination rather than general water contamination (Health Canada, personal communication, 2008).

During a USEPA study conducted in 2004, 327 passenger aircraft were randomly tested at 12 airports that served both domestic and international routes. The USEPA analysed the drinkingwater samples from galleys and lavatories for total coliforms (in the case of a positive result for total coliforms, the sample was tested for E. coli/faecal coliforms), total residual chlorine, heterotrophic plate count, and total nitrate and nitrite. In regard to the presence of microorganisms, 15% (49/327) of the aircraft tested positive for total coliforms in one or more sampling sites, and 4.1% (2/49) of these total coliform–positive aircraft also tested positive for E. coli/faecal coliforms. Twenty-one per cent of the aircraft tested had a non-detectable chlorine residual (USEPA, 2008).

The APHA study conducted in 1999 examined 850 samples of water from mains, bowser and aircraft sources from 13 airports in the United Kingdom. Pseudomonas aeruginosa was detected in 27% of all samples, total coliforms in 7.8%, E. coli in 0.4%, enterococci in 1.2% and sulfite-reducing clostridia in 0.4%. Of the samples with coliform contamination, 7.9% had contamination with faecal indicators, compared with 1.3% of samples without coliforms (APHA, personal communication, 2008)