Ice cubes, a nice addition to a range of drinks. Coffee shops, bars and restaurants, it’s pretty hard to miss them. Apart from the disappointment of returning only a few moments later to your watered down beverage, could there be something potentially far worse happening to your drink?

A study conducted on 60 samples of ice cubes produced at domestic, restaurant and industrial levels were examined for microorganisms other than enteric or normally ‘harmless’ bacteria. It showed there was a significant difference in the amount of bacterial contamination at varying levels of ice cube production. The study found that ice cubes made at home or from ice machines in pubs and restaurants contained significantly more bacteria than industrial level ice cubes (5).

According to the ranges produced from the study, 1kg of ice made from a commercial ice machine could contain diseases hidden in ice and as much as 63,100 bacteria which is about 147 per ice cube*(1)(5). The cocktail of bacteria found includes Pseudomonas, Bacillus, Acinetobacter and Staphylococcus, of which could be an indication of contamination by human contact (4) and a lack of cleanliness of the ice machines used within industries.

More recently, an investigation by BBC’s Watchdog discovered that ice from a number of popular fast food and coffee chains contained unsettling amounts of faecal bacteria such as Enterococcus and Escherichia coli (E. coli)(6). According to the Drinking Water Inspectorate (DWI): an independent body concerning UK water standards, any level of such contamination is deemed unacceptable to drink and an immediate response is required to identify and remove sources of faecal contamination (2).

Diseases hidden in ice

Bacteria are everywhere and can survive even the harshest of environments (3). It’s therefore not a surprise that ice, even when made from sterile water, can be contaminated further down the production line. It does however shed some light on the current hygiene standards our food and drinks under go.

Although a bit chilling, luckily a number of drinks accompanying your ice combat bacteria through their naturally inherent properties. Drinks such as vodka, whiskey, peach tea and coke containing either alcohol, CO2 or the right levels of pH and can reduce the numbers of bacteria consistently (5).

So it’s likely you won’t be left feeling ill from the occasional iced beverage. However it is certainly food for thought.

*2.5 cm3 ice cube.

References:

  • 1. CRC Handbook of Chemistry and Physics. Journal of the American Chemical Society. 2006; 128 (16):5585-5585.
  • 2. Drinking water safety. London: Drinking Water Inspectorate; 2009.
  • 3. Rampelotto P. Extremophiles and Extreme Environments. Life. 2013; 3 (4):482-485.
  • 4. Otto M. Staphylococcus colonization of the skin and antimicrobial peptides. Expert Review of Dermatology. 2010; 5 (2):183-195.
  • 5. Settanni L, Gaglio R, Stucchi C, De Martino S, Francesca N, Moschetti G. Presence of pathogenic bacteria in ice cubes and evaluation of their survival in different systems. Annals of Microbiology. 2017; 67 (12):827-835.
  • 6. Watchdog – Fast Food Ice – BBC One [Internet]. BBC. 2017 Available from: http://www.bbc.co.uk/programmes/articles/r8TGX1qjHstSwG1XHTzm4X/fast-food-ice