Oh, Facebook! Isn't it just a cornucopia of useful information! The other day I even read something on it that made sense.

It was about a family, of unknown origin, who had gone on a picnic. Then, on "Monday, two family members were admitted to the hospital. He [presumably the father] died on Wednesday. Autopsy report: Leptospirosis."

Yes, he had died as a result of drinking from cans contaminated by mice urine, which presumably occurred when the drinks had been in storage. Eew, disgusting. Who'd want to die of mouse-urine poisoning? But equally, who would think to ask shopkeepers to wipe down their Heineken or Tsingtao (which should be spelt "Chengdou")? Thank you, Facebook.

A few days after reading this disturbing story, I went with L and F on a trip to Meizhou, a Hakka stronghold in Guangdong province. The prospect of an excellent time was made even more likely by a restaurant across the street from the hotel: all pink plastic chairs and an atmosphere so laid-back it lay prone.

The Chengdou was dewy, and so what if the "glasses" were made of plastic and not much thicker than a condom? At least we got a fresh, unopened packet of them; the wrapping was a bit tight but I forced it off, manfully, imagining I was peeling the trousers off a 1970s glam-rock star. Beer beckoned and all was well with the world.

I handed out the cups two at a time, one inside the other to make them a little thicker and sturdier. Cheers!

But … what was that smell? It was like a petrol-station toilet for truckers, probably uncleaned since the aforementioned 70s. Could it be that the beer wasn't really … beer?

I sniffed again. Now my hand smelt like that toilet - you know, the one in Trainspotting.

The plastic glasses had clearly been stored in the loo, or at least some storage room that had been used as a loo, probably by rodents as well as humans. Life in the mainland has taught me that such assumptions are reasonable. But if it hadn't been for Facebook and the leptospirosis story - wherever it originally came from - I would not have been quite so alert to the issue of beer hygiene, nor the source of any bad smells.

After a quick bout of handwashing, we were drinking beer as if nothing untoward had passed. We accepted the offer of a new packet of cups, though. And yes, we sniffed it first.