Ice is dangerous stuff – it can cause your feet to whip out from under you and leave you humiliated on your rear-end; it can cause your vehicle to skid, and it can prevent planes from flying. It can also give you food-poisoning.
Ice is food
Ice is food. It seems a bit of a strange statement but, when it comes to the potential to cause harm, ice needs to be considered as a food product and given appropriate respect. In a rather sobering report titled “The Dirty Secrets Lurking in Your Ice Machine’, the myriad of ways in which ice can cause harm are carefully articulated. To put the risk into some sort of context, on average American consumers each buy 4 bags of ice each year; and between 1998-2016 ice featured in the top 10 vehicles for food borne illness in the CDC data. So, what are these ‘dirty secrets’?
First up, we have mould and slime. To grow and flourish, mould needs a food source, a place to grow and moisture, all of which can be found in the kitchen. Where it becomes an issue with ice makers is when the mould chooses to bed down in the drop zone of the ice maker, in the scoop used to fetch ice, or in the water receptacle for making ice. It is recommended that any ice-making facilities are cleaned regularly, particularly when there is abundant food for the mould to grow (no matter how clean our kitchens are, there is always the potential for airborne particles of food, grease and yeast, which provide tasty meals for moulds). In a study reported in the Journal of Applied Microbiology, samples of ice from a number of different sources (home ice making, bars and pubs, and commercial ice making) were analysed. Moulds were detected in almost all samples (and yeasts developed in the home made and bar made ice samples). The authors in that study found that even after adding alcohol or other drinks, the viability of the microfunghi did not reduce. Although, another study reported some risk reduction with the addition of alcohol to ice (as in, I’ll have that single malt on the rocks) – while the results are ambiguous it really is better not to add mould, spores or other nasties to you evening tipple.
The unspeakable item number 3
The authors on the Dirty Secrets list fecal matter as item number three – we choose to skip over this with the simple statement – wash your hands. There really is nothing else to say.
Next up is the risk of dust and dirt; while this is true for any food preparation, it’s important to note that ice machines can be fan cooled, meaning they pull in air to cool the water to make the ice. Regularly cleaning air filters is a must (and not just for food safety, but for appliance efficiency as well).
The (nearly) invisible risks
Mould, slime, dirt and dust can all be seen (ok, so can fecal matter). Arguably the most dangerous to human health though is the unseen – the presence of Salmonella, E. Coli, and Norovirus. As an aside, Salmonella is named after the scientist who discovered it, Dr Salmon, and not the fish. While there are reports of cases of salmonella, one of the most common causes is the virus: Norovirus. In one case, authors found that the presence of norovirus in ice made from un-boiled water sickened a number of Taiwanese students who had consumed iced tea. In another reported case, a number of people were sickened at a Christmas buffet – the culprit was the ice that was produced in machines near a leaky air vent. There are many reported cases of Norovirus and ice and, aside from basic good hygiene (see, the CDC’s fact sheet on preventing Norovirus here, there is very little that you can do – one ‘clever’ commentator suggests boiling your ice cubes before consuming. Similarly, the presence of E. coli is a hygiene issue addressed using the same suggested interventions as Salmonella and fecal matter. Wash your hands.
Cockroaches and critters The cheerful authors of the ‘Dirty Secrets’ list cockroaches and other critters as the last two items of potential contamination. A bit like fecal matter, these are big on the yuck factor. Many critters are attracted to food preparation areas and their presence is something that must be managed. It is easy to summarise probably the biggest two take-homes about ice are: 1) it is a food and, 2) wash your hands. Or, putting it another way, if you are in a premise where you would be reluctant to eat the food, it is wise to avoid the ice.
(As an aside, the controversial song Ice, ice baby was released in 1990 and is remembered for the legal wrangling associated with the singer not paying royalties to David Bowie and Queen – it was also voted one of the worst 50 songs of all times - further ‘evidence’ of the risks of ice).