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Is Technology Leading to Microbial Cross-Contamination and Pathogen Spread in the Airport Environment?

Shelomo Alfassa,  Certified, Occupational Safety and Health Specialist 

5 February 2018


It’s not a far off assumption that members of the public are not washing their hands prior to or after boarding a commercial aircraft. However, new procedures such as the gate agent taking a mobile phone from a passenger, scanning it on an electronic boarding pass reader, then handing it back to the passenger, may mandate this at some point. It seems modern electronic boarding passes are openly causing cross-contamination of microorganisms between aircraft employees and the general public. And while environmental and human contamination related to microbial cross-contamination and pathogen spread in the airport space is not a commonly discussed topic, the question that needs to be asked, is, should it be a paramount concern for public health officials?[1]


It's well known that direct skin to skin contact and/or passing something between two individuals is a way that microorganisms can cross-contaminate. While human hands are harbingers of bacteria and viruses (among normal flora), so too are inanimate objects. Combine this in a situation where infrequent hand washing is the norm (such as traveling through an airport), and this can evolve to a point where infection becomes inevitable. There is a definite change occurring at airports across the world, as paper boarding tickets are rapidly bring replaced by electronic boarding tickets on mobile phones.

Formerly, one would obtain a paper boarding pass and hold on to it until they walked up to the aircraft gate to board their plane. They would give the boarding pass to the gate agent, they’d scan it and return the stub. And while using a mobile phone to do the same thing (passing it back and forth) superficially sounds similar, the big difference is that bacteria grows differently on plastics vs. paper.

In ambient air, paper (either made of wood pulp or cotton fibers), is not a medium which stays moist for long. Inherently, both wood pulp and cotton fibers dry rapidly, this manifests as having a natural bacteriostatic effect. Materials which once wet from moisture (i.e. from perspiration of the hand or intimate moisture from the nose or mouth) will have the opposite effect—this includes mobile phones, which will also have natural skin oils among the moist mixture. Due to their plastic shell, cell phones are prone to the growth of biofilm, an assemblage of microorganisms that cannot be easily wiped off and exist in a polysaccharide suspension; this type of biological material is not easily removed by gentle rinsing. “Biofilm represents a problem” as it can contribute to infections in humans.[2]

A 2014 Time magazine article entitled, “Bacteria Thrive for Days on Airplanes” discussed how bacteria lived on fomites inside an airplane cabin. This included on seatback pockets for 8 days, leather seats 7 days, plastic window shades for 3 days, and plastic tray tables for 3 days.[3]

The Situation

What is occurring, is that as passengers line up to board the aircraft, they step up to the gate, hand their mobile phone to the gate agent who takes the mobile phone from the passenger, scan it across a laser-sensor (which reads the screen) and hands it back to the passenger. This interaction of the gate agent handing the passengers mobile phone—then taking the next passengers phone, and so on, is openly cross-contaminating all the phones on the aircraft.

For the purposes of this discussion, we are not focusing the initial Transportation Security Administration (TSA) Credential Authentication Technology and Boarding Pass Scanning System (CAT/BPSS) scanners that are at the entrance of the security screening area. We are focusing on the airline boarding gate barcode readers that customers use right before stepping onto the jet way proximal to the aircraft. These are typical modern glass top readers which can interpret emailed 2D barcode boarding passes; these are commonly displayed on mobile phones and tablets. Austrian Airlines was the first airline to offer electronic boarding passes that could be pulled up on mobile phones in the mid-2000s,[4] today, these are in use around the United States and across the globe by most carriers.

Mobile phones are prone to being “dirty,” and medical science has abundantly confirmed this. A 2012 study reported that mobile phones of health care workers are “potential vectors for transferring nosocomial pathogens” between patients and the community.[5] The results of this study demonstrated that out of 183 tested phones, 179 came back positive for bacteria, including Escherichia coli, MRSA and ESBL-producing E. coli.[6] In 2014, the Journal of Epidemiological Global Health reported on a study which 112 phones were swabbed and analyzed for bacterial colonization. Of the 112 phones studied, 94.6% were colonized with bacteria pathogens, including Staphylococcus Epidermidis, Bacillus spp., Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, and others.[7] A 2015 study found that mobile phones were reservoirs for the transmission of pathogens, and that out of a test group of 316 phones, 100% contamination was found.[8] Another study, this one in 2016, demonstrated that of 110 university student’s phones that were tested, 77.3% of the phone were infected with Coagulase-negative staphylococci (CoNS) and Staphylococcus aureus.[9]


Inadequate hand hygiene may result in cross-transmission of pathogens and hand colonization or infection. Several studies have shown that microorganisms can survive on hands for differing times, and this may be from minutes to many hours. “Pathogens of fecal, nose or throat, and skin origin are most likely to be transmitted by the hands.”[10] The literature clearly demonstrates that “contaminated hands could be vehicles for the spread of certain viruses and bacteria.”[11] Handing someone a fomite such as a mobile phone which has spent much time in contact with someone's face and hands, then passing it back, is an assured way of transmitting microorganisms from one person to another. Cross-transmission of organisms by those with contaminated hands is heightened by variables such as moisture and the lack of handwashing.[12] What we realize is that examining environmental contamination related to microbial cross-contamination and pathogen spread (including the flu virus) in the airport space, should be a paramount concern for public health officials.[13] In late 2017, microbiological tests conducted at three major (non-disclosed) airports, demonstrated that the highest bacteria / fungal cell counts were located on the screens of self-service boarding pass kiosks, some 253,000 colony forming units (CFUs). This number is 2.5 times that of CFUs found on the airplane toilets, and 21.8 times higher than the number of CFUs found on the airplane’s tray tables.[14]

Utilizing the current method to scan individual boarding passes: Hand-Phone-Hand (Scan) Hand-Phone-Hand presents a tangible risk that a number of opportunistic organisms (which may include bacteria, fungi and viruses) may be spread via the customers’ mobile phones. This type of transmission may play a role in the development of subsequent microbial-related illnesses. The benefit of innovative technology that expedites the boarding of passengers, needs to be weighed against the potential for microbial cross-contamination and the potential, in some circumstances, for infection.



[1] Griffith CJ, et al. Environmental surface cleanliness and the potential for contamination during handwashing. American Journal of Infection Control. 2003;31:93–96.

[2] Balagna, C. et al., “Silver Nanocluster/Silica Composite Coatings Obtained by Sputtering for Antibacterial Applications” in Njuguna, James. (Ed.) Structural Nanocomposites: Perspectives for Future Applications. Springer: Aberdeen, UK. 2013. 226



[5] Ustun C, Cihangiroglu M. Health care workers' mobile phones: a potential cause of microbial cross-contamination between hospitals and community. J Occup Environ Hyg. 2012;9(9):538-42.

[6] Ustun C. Op. cit.

[7] Nwankwo EO, Ekwunife N, Mofolorunsho KC. Nosocomial pathogens associated with the mobile phones of healthcare workers in a hospital in Anyigba, Kogi state, Nigeria. J Epidemiol Glob Health. 2014;4(2):135-40.

[8] Pal S, Juyal D, Adekhandi S, et al. Mobile phones: Reservoirs for the transmission of nosocomial pathogens. Adv Biomed Res. 2015;4:144.

[9] Kotris I, Drenjančević D, Talapko J, Bukovski S. Identification of microorganisms on mobile phones of intensive care unit health care workers and medical students in the tertiary hospital. Med Glas (Zenica). 2017;14(1):85-90.

[10] Greig, J.D. (2010). Infective doses and pathogen carriage. Public Health Agency of Canada. Food Safety Education Conference, Atlanta Georgia; 6.

[11] WHO Guidelines on Hand Hygiene in Health Care: First Global Patient Safety Challenge Clean Care Is Safer Care. Geneva: World Health Organization; 2009. 7, Transmission of pathogens by hands.

[12] WHO Guidelines on Hand Hygiene in Health Care. Op. cit.

[13] Griffith CJ, et al. Environmental surface cleanliness and the potential for contamination during handwashing. American Journal of Infection Control. 2003;31:93–96.

[14] Germs at the airport. (2018, January 12). Austin, TX.

Tags: Airlines, Pathogens, Microorganisims, cell phones, boarding passes

APA Citation

Alfassa, S. (2018). Is technology leading to microbial cross-contamination and pathogen spread in the airport environment. New York

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