In an analysis of ice cube samples collected from bars, restaurants and canteens around Switzerland last year, 26 percent fell short of legal health standards, said Sunday paper SonntagsBlick, which released the figure prior to the report’s official publication.

The presence of bacteria including pseudomonas, E. coli and enterococci is “a clear sign of unsanitary production of ice cubes,” Otmar Deflorin, president of the  cantonal chemists association and head of the Swiss federal laboratory in Bern, told SonntagsBlick.

The primary cause is a lack of hygiene in bars and restaurants, where ice machines may be badly cleaned and maintained, he said.

Machines are often placed in basement and cellars, with no one taking responsibility for them.

However no charges have yet been brought, said Deflorin, because although the legal limits were exceeded, the amount of bacteria found was not enough to present a danger to human health.

Some disagree. Sara Stalder, director of a consumer protection group, said the bacteria levels could present a health risk to some, particularly those with a suppressed immune system, for whom such bacteria could cause “serious gastro-intestinal illnesses”.

“Abroad you are always careful with ice,” she told SonntagsBlick, “but in Switzerland one would never expect one in four ice cubes to exceed legal limits.”

“If you pay for your food you expect impeccable hygiene,” she added.

Stalder is calling for a change to the established practice of bars automatically adding ice cubes to drinks.

“It should be normal practice that you explicitly ask for ice your drink, rather than it being automatically added to the glass,” she told the paper.

But Casimir Platzer of industry association GastroSuisse disagreed, saying customers would be “disappointed” to not be served ice automatically.