You probably haven't given much thought to the ice that makes your drink frosty. Ice is the cool savior of heated moments of sweaty dehydration. It's the subject of sweltering summer songs, like July 1990's "Ice Ice Baby." Why question the ice when it's so nice?
In Walden, Henry David Thoreau might have been one of the first to do so, when he documented the rise of the commercial ice cube industry and the human consumption of ice. Ice wasn't popular until the early 1800s, when "Ice King" Frederic Tudor began the first-ever ice empire, harvesting blocks from Walden Pond at the same time Thoreau was Bon Iver-ing in his cabin. "Thus it appears," Thoreau wrote, "that the sweltering inhabitants of Charleston and New Orleans, of Madras and Bombay and Calcutta, drink at my well."
While Thoreau's concerns were less about health as he pondered the abstract concept of ice access and global movement, if you're not trying to write the next great American novel you'll probably be more concerned with things like bacteria, mold and, well, human sh*t contaminating your icy beverage. Since the early days of the Ice King, research has unfortunately shown there's more in those ice cubes than dreams of self reliance. The Huffington Post talked to Dr. Pritish Tosh, an infectious diseases physician and researcher at the Mayo Clinic, and Martin Bucknavage, the senior food safety extension associate at the Department of Food Science at Pennsylvania State University, for some clarification on what exactly might be lurking in your ice cubes this summer (or any season).
Since the Safe Drinking Water Act in 1974, the Environmental Protection Agency (EPA) has done a good job of making sure harmful levels of bacterial pathogens are being kept out of the U.S. water supply. Dr. Tosh said that it's only very rare circumstances in which you should be worried about ice water being dirty from the start. However, EPA inspectors don't live in ice machines to ensure that the once-clean water isn't being contaminated during the freezing and dispensing process. One 2011 study that focused on ice dispensers in Las Vegas food establishments found that 33.3 percent of the ice samples "exceeded the EPA limits set for heterotrophic bacteria concentration for drinking water" and 72.2 percent were "positive for presumptive coliform bacteria presence." Bucknavage also suggested that it wasn't uncommon for bacteria to accumulate in ice makers, potentially contaminating the ice.
That said, a restaurant that has bacteria issues in its ice probably has bacteria issues everywhere, making it unavoidable. While there may be occasional concerns about the composition of the ice at some establishments, Dr. Tosh said that the main issue is the threat of ice being cross contaminated if it touches other foods being served, such as meat. If the restaurant performs poor food handling practices in general, that can be a problem. But contaminated ice by itself is a problem and as Bucknavage said, "ice is used as a ready-to-eat food, and like any kitchen appliance or utensil that directly touches food, we have to treat the ice machine in the same way."
Bucknavage suggested that mold may be the biggest culprit of ice contamination. Mold is too often found in the ice machines of local restaurants, but can grow in home freezers as well. The cold temperatures of freezers may make it harder for mold to grow, but the problems start when freezers are regularly turned off or for extended periods of time. Restaurant owners should make sure to clean their machines several times per year, and Bucknavage advised homeowners to do the same:
"If your freezer [or] ice maker has been off for sometime, that ice maker should always be cleaned before using," he said. "This can be an issue with people who have a summer home where the unit has been off for a number of months. ... People can have a reaction after consuming a slug of mold coming from the ice. Knowing this, the average person should put forth effort to keep their ice machine clean. Why take on risk when a regular cleaning will prevent issues?"
3. Whatever was on those hands.
If you use an ice scoop without washing your hands and then drop the scoop back into the ice, then the cubes could become contaminated with whatever was on your grubby mitts -- or already on the scoop. The same goes for your home, if you pick the ice out of the tray with your hands without washing them. You may remember to wash your hands before meals, but do you remember to do so every time you're pouring a drink with ice? Probably not, especially for those late night drinks.
Debra Huffman, a microbiologist with the University of South Florida, spoke with NBC News after a 15-year-old boy died from contaminated ice that could have been prevented from hand-washing. "Most people don’t realize that not washing their hands could cause death. They just don’t see the risk," she said. "It’s not going to smell funny. It’s not going to look funny. These are microscopic, and so you’re not going to see it. You wouldn’t known it happened."
In 2007, the Chicago Sun Times found that nearly 20 percent of 49 restaurants and hotel bars in Chicago had ice contaminated by high levels fecal coliform. According to a summary of the Sun Times report, "most of the positive test samples came from ice-bins used by waitstaff or otherwise exposed sources."
So soap up and be wary of those ice scoops. "Ice scoops need to be cleaned, just as any other kitchen utensil," Bucknavage said. "Finally, we don’t want people sticking their hands in the ice of the ice machine. Always use a clean scoop because the hands can be a source of bacteria." Including the kinds found in fecal matter, apparently.
While these contaminants may be disturbing, the average health risks from these types of dirty ice are fairly minimal to the average immune system. Both Dr. Tosh and Bucknavage repeatedly stressed that the normal immune system can handle these contaminations and the real trouble can come when poor food handling practices are taking place in general. Occasionally, deadly viruses can be transmitted through ice, though this is rare. Regardless, you should play it safe and avoid contaminating your home's ice by regularly cleaning storage devices. When going out, generally avoid restaurants with poor marks for cleanliness, as that could carry over to their ice as well. You wouldn't want someone to stick their hand in your drink before consuming it. Why should you let someone get into in your ice?