You may want to make your iced coffee at home for now—at least, if you want to avoid accidentally drinking small amounts of shit. An investigation found that not one, not two, but three major coffee chains have fecal bacteria in their ice. The Guardian reports that the BBC's Watchdog undercover investigation found that ice from Starbucks, Caffè Nero, and Costa Coffee all contained fecal coliform bacteria. The worst offender was Costa, as a positive test was found for seven out of ten samples of coffee from ten different coffee shops in the UK; three out of ten samples were found positive for Starbucks and Caffè Nero.

Food-borne pathogens expert Rob Kingsley of Quadram Institute Bioscience told the Guardian that this crappy news shouldn't be taken lightly:

Coliforms are an indicator of fecal contamination which means that essentially anything which is in feces could be in that ice. It is an indicator that somewhere there has been some kind of breakdown in hygiene or the source of the water used for this ice...I would certainly think twice about eating something which may contain faecal contamination at that level, where it is detectable.

Microbiologist and senior lecturer at Leeds Beckett University Margarita Gomez Escalada, who carried out the study for BBC, told the Guardian that the ice was likely touched by contaminated hands, but that the ice machines and buckets may also not have been properly cleaned:

The levels allowed by law of bacteria in tap water are super low, so we would find say maybe 10 microorganisms per milliliter—we found hundreds per milliliter... The fact that we have found so many bacteria, it just increases the risk [of getting sick]. Some of the bacteria we identified were actually what we call opportunistic pathogens, which are bacteria that to healthy people do not often cause disease, but they cause disease to people [whose] immunity is reduced.

But if you just can't give up your iced coffee even with a little poo, Tony Lewis, head of policy at the Chartered Institute of Environmental Health, says that it's not anything to worry about. “Given that there are tens of thousands of coffee shops around the UK, we have to put this into context,” he said. “The samples that the BBC have got indicate a problem, or problems, in respect to the Costa and the Caffè Nero and the Starbucks that they sampled—but at the end of the day the public should not panic about this. You can’t generalize from the small sample size that we have got here.” So, you can make your own conclusions. But in the meantime, here's this.