Ice is kind of the Jan Brady of the food world. One of the first food safety talks I ever saw was about ice. The session was wittily titled, The Forgotten Food.
Restaurant servers, who often don’t see themselves as food handlers, fill up glasses with ice (sometimes with a scoop, sometimes not). A cup-filling server, if diagnosed with Hepatitis A, ends up causing line-ups of patrons looking for post-exposure shots.
For folks traveling to countries where the safety of water is compromised, ice cubes (made from that water) can be a missed risk (and Canadian provinces tourism boards try to capitalize on this, see below).
A paper by Serdarvic and colleagues published in Epidemiology and Infection (which should be renamed to Outbreak Junkies Monthly) details another ice-related outbreak associated with a 2008 Lake Michigan dinner cruise. 41 out of the 72 cruisers came down with a mix of gastro illnesses (Shigella, Giardia, Cryptosporidia) after consuming ice-containing drinks. The paper details that prior to the cruise, rainfail cause a bunch of diluted sewage released into the lake – and that the hose used to pipe potable water into the boat’s water tank was likely contaminated due to user error.
Multi-pathogen waterborne disease outbreak associated with a dinner cruise on Lake Michigan
F. Serdarevic, R. C. Jones, K. N. Weaver, S. R. Black, K. A. Ritger, F. Guichard, P. Dombroski, B. P. Emanuel, L. Miller and S. I. Gerber
We report an outbreak associated with a dinner cruise on Lake Michigan. This took place on the same day as heavy rainfall, which resulted in 42·4 billion liters of rainwater and storm runoff containing highly diluted sewage being released into the lake. Of 72 cruise participants, 41 (57%) reported gastroenteritis. Stool specimens were positive for Shigella sonnei (n=3), Giardia (n=3), and Cryptosporidium (n=2). Ice consumption was associated with illness (risk ratio 2·2, P=0·011). S. sonnei was isolated from a swab obtained from the one of the boat’s ice bins. Environmental inspection revealed conditions and equipment that could have contributed to lake water contaminating the hose used to load potable water onto the boat. Knowledge of water holding and distribution systems on boats, and of potential risks associated with flooding and the release of diluted sewage into large bodies of water, is crucial for public health guidance regarding recreational cruises.