You drop a piece of cucumber on the floor. Do you immediately throw it in the bin or reassure yourself of the age-old “five-second rule” and reckon it’s fine to pop it in your mouth after a quick rinse?

If you fall into the latter camp, John Tregoning, professor of vaccine immunology at Imperial College London, has some bad news. He refers to three studies into bacteria transfer that all point towards the rule being false.

In the first, scientists looked at what happens when a range of foods (bread, buttered bread, watermelon and gummy bears) were dropped on a range of surfaces (tile, steel, wood, and carpet) that had been coated with bacteria. “They transferred almost immediately,” he says, adding that the worst combination for transfer happened when wet food hit a solid surface (watermelon on tile or steel).

Another study – where cooked sausage was dropped on to surfaces – showed that bacteria transferred on to the meat even if they had been applied to the surface hours earlier. It showed that “if you put a piece of contaminated chicken on to a work surface and then, two hours later, drop your piece of bread on to it, you can still pick up bacteria from it. It’ll be there for about 24 hours,” he says.

The final paper looked at the “five-second rule” for medical objects in the operating room. Perhaps unsurprisingly, it found that if surgeons drop something on the floor, they need to wash that instrument with detergent for it to be safe to use again.

What does all this mean for your fallen cucumber? “I think you have to accept it’s gone,” says Tregoning. Rinsing it with water won’t be enough to guarantee it’s clean. That’s especially the case if you’re particularly susceptible to infections, or if your dog might have walked something terrible through the house (even hours earlier).

THE GUARDIAN

Saudi Arabia’s national digital platform Tawakkalna is providing Hajj-related government services in 19 languages for pilgrims and workers during the 1447H Hajj season, as part of wider efforts to improve the pilgrimage experience through advanced digital solutions.

The initiative comes within the efforts of the Saudi Data and Artificial Intelligence Authority to strengthen integration between government service entities during Hajj and support pilgrims throughout their journey, from arrival in the Kingdom and entry into Mecca and the holy sites to visits to the Prophet’s Mosque in Madinah and departure back to their home countries.

The app supports Arabic, English, Indonesian, Hindi, Urdu, Turkish, French, Bengali, Persian, Malay, Russian, Chinese, Filipino, German, Dutch, Japanese, Italian, Spanish and Portuguese.

Pilgrims can access a range of services through the platform, including Hajj permits linked to the unified digital Hajj permit platform “Tasreeh”, as well as permits related to entering Mecca, work authorisations, volunteer permits and vehicle permits issued by various government entities.

According to officials, Tawakkalna is designed to serve as a trusted digital companion for pilgrims by supporting daily movement and offering a smoother and safer digital experience during Hajj and visits to Madinah after the pilgrimage.

The app also allows users to book visits to Al Rawdah Al Sharifah through the Nusuk gateway service integrated into the platform.

Additional services available during Hajj include multilingual access to the Arafah sermon, an emergency assistance service called “Assefni”, live weather updates for the holy sites, Qibla direction, prayer times and digital Quran services.

Saudi authorities said the services are part of broader efforts aligned with the Pilgrim Experience Programme under Saudi Vision 2030, which prioritises improving services for pilgrims and Umrah performers through smart technology solutions.

The Tawakkalna platform currently offers more than 1,300 services in cooperation with over 350 government entities across sectors including health, education, justice, tourism and professional services, with more than 35 million users registered on the app.

GN

It used to be thought that the lungs couldn’t regenerate,” says Dr Charlotte Dean, head of the lung development and disease group at Imperial College London. “But we know now that’s not the case. Broadly speaking, they can repair when you quit smoking.”

Smoking is in effect damaging your lungs, Dean says, and the lungs have a substantial capacity to heal themselves. They have evolved to cope with pollution or getting infected by bacteria or viruses. “Because they’re so vital – you can’t survive without your lungs – they needed to have this capacity,” she says.

Dean says this shouldn’t be used as an excuse to smoke, though; smoking and vaping expose your lungs to more toxic particles than they can cope with. Importantly, everyone is different and some people’s lungs will not be able to regenerate as well as others and so will be much more susceptible to permanent tissue damage from smoking.

“While it’s broadly true that if you stop smoking you can revert to having much better lung health, it doesn’t mean you’re completely out of the woods. You may well have triggered mutations or genetic changes or tissue damage, and those things can affect your overall lung health, meaning that the decline as you age will come quicker or could lead to cancer.”

She would encourage smokers to quit as early as possible as – similarly to how your bones don’t mend as well as you age – your lung tissue gets less effective at repairing itself as you get older. A healthy lifestyle can help. “Exercise is really important,” says Dean. “Just like how when you exercise you keep your muscles healthy, in a way the lungs are the same. You build up the capacity for gas exchange to happen more effectively, to provide oxygen around the body.”

The Guardian