A lab experiment released by travel provider JRPass found that passports carried far more bacterial growth than other common travel items, with samples from the document testing well above shoes, checked luggage, hand luggage, phones and coats.
The finding is getting attention because it flips a familiar travel assumption. Many people worry most about shoes, suitcase wheels or airport trays, but the experiment pointed instead to the item travelers repeatedly hand over at check-in counters, security lines and border checkpoints. The release, published in February and picked up by several outlets this month, framed passports as the most contaminated of six travel categories tested. The immediate significance is less about proving a health emergency than about showing how often-handled objects can quietly collect bacteria during routine trips through crowded transit hubs.
According to accounts of the experiment, JRPass used nutrient agar in a petri-dish microbial culture test to compare samples taken from six common travel items: airport clothing, mobile phones, hand luggage, shoes, checked luggage and passports. The company said it tested three items from each category to check for consistency, then measured bacterial growth in colony-forming units, or CFUs. Passports ranked first by a wide margin at 436 CFUs. Checked luggage was next at 97, followed by shoes at 65, hand luggage at 56, phones at 45 and coats at 15. The spread between the top result and the rest of the field is the detail that helped push the story beyond ordinary travel-hygiene chatter. Rather than clustering near one another, the results placed passports alone at the high end of the chart, with every other item finishing below 100. That contrast became the core headline finding in the coverage that followed.
Primrose Freestone, an associate professor in clinical microbiology at the University of Leicester, said the result makes sense because passports move through many hands and many surfaces during a trip. In comments carried in follow-up coverage, Freestone said human hands already carry normal bacteria and also pick up microbes from crowded settings such as airports and public transport hubs. The more often a passport is handled by different people, she said, the more bacteria, fungi and even viruses can be deposited on its surface. That explanation helped turn a novelty statistic into a more concrete account of why the numbers may have broken so sharply in one direction. Passports are handled at check-in, at security, at boarding and at immigration, then tucked into pockets, bags, bins and counters before being handled again. Unlike phones or bags, they are also less likely to be cleaned regularly. The public reporting did not suggest the document itself is uniquely dangerous. Instead, it described the passport as a high-contact object that picks up contamination because of where it travels and how many hands touch it along the way.
The study’s limits are as important as its headline result. The experiment measured bacterial growth from swabbed items, not actual illness among travelers. It was also commissioned by a travel company rather than released through a peer-reviewed medical journal. That does not automatically make the results unsound, but it does place the finding in a different category from a formal academic study with outside review and a published methods section. The available reporting gave a broad description of the test but did not lay out every methodological detail that would usually matter in scientific scrutiny, including how the items were selected, whether the sampled trips were comparable, how recently each item had been cleaned, or what kinds of bacteria made up the total counts on the passports. The gap matters because not all bacteria carry the same risk. Some are common background microbes that appear on skin and shared surfaces every day. In other words, the experiment was useful as a snapshot of contamination, but not as a direct measure of danger.
Even with those caveats, the story landed in a broader moment of interest in the hidden grime of travel. Reports over the past year have focused on suitcase wheels, tray tables, seatback pockets, trolley handles and hotel-room touch points. Those stories usually follow a familiar script: a seemingly ordinary object is tested, the numbers come back higher than expected, and a microbiologist explains how public spaces move germs from surface to surface. What made the passport result stand out was the surprise factor. Travelers already accept that shoes touch dirty floors and bags roll through crowded terminals. A passport, by contrast, often feels like a protected object, something kept in a sleeve or zipped compartment. The JRPass experiment challenged that assumption by showing that an item associated with security and careful storage may still accumulate the heaviest bacterial load simply because it changes hands so often. That everyday handling, not visible dirt, appears to be the main reason the document topped the list.
The timeline behind the story is straightforward. JRPass published the experiment in February. Travel + Leisure reported on it March 5, describing the petri-dish culture test and the six categories sampled. The New York Post followed March 11, adding comments from Freestone that helped explain why passports would outscore bulkier and visibly dirtier items. By then, the findings had begun circulating more widely through travel and lifestyle coverage, where the passport number became the headline figure repeated across summaries of the test. The most consistent facts across those reports are the ranking itself, the 436-CFU result for passports, the wide gap between passports and checked bags, and the explanation that repeated handling in dense travel environments can build up contamination. Less clear are the finer points that would sharpen the scientific picture, including the precise species breakdown of the microbes found and whether the same pattern would hold across a larger sample collected over time.
There is also a practical reason the result spread so quickly. Passports sit at the center of travel stress. They are touched when plans are moving, lines are long and attention is split among bags, documents, children, phones and gate changes. That makes them a strong symbol for the invisible residue of travel itself. Freestone’s comments gave that symbol a scientific frame, saying airports and transport hubs are high-contact places where microbes move easily from hand to hand and surface to surface. Her role in the coverage also helped anchor the story beyond a branded study release. The University of Leicester identifies her as an associate professor in clinical microbiology, and her comments in the coverage stayed close to the mechanics of transfer rather than dramatic claims about outbreaks or immediate illness. That restrained framing is part of why the story has held up: the finding is striking, but the explanation behind it is ordinary, rooted in repeated contact, crowded public settings and infrequent cleaning of a document people rarely think of as a germ collector.
As of March 12, the public conversation around the experiment remains centered on that contrast between expectation and result. The next milestone is likely to be whether JRPass or outside researchers release fuller methodological details or whether new testing by other groups confirms the same ranking across a larger pool of travel items.
Author note: Last updated March 12, 2026.