Boaters have become familiar with the deterrent effects of Copper; ever since TBT was banned as an antifouling because it caused lady Dog Whelks to grow penises we've depended on copper as the active substance to keep slime and barnacles at bay. Now hospitals have found that copper pipes kill superbugs, too.
So sorry to amateur push-fit plumbers everywhere; it's back to the Yorkshire fittings and the brazing torch for peace of mind. And throw out those plastic chopping boards that Nanny told us all to use a few years ago; they breed bacteria that are killed by the old wooden 'unhygienic' ones. And Silver kills bugs, too - which is one of the better reasons to keep using Silver cutlery and that Silver lined sauce pan.