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Houston Department of Health and Human Services > Food Inspection and Safety (Consumer Health) > Food Safety Tips > Slime in the Ice Machine

"Slime In The Ice Machine:" How To Prevent Ice Contamination

It's amazing how this one little phrase speaks volumes about the cleanliness (or lack thereof) of some of Houston's food establishments. Most people think this sentence is the best part of the evening news; it keeps them smiling. If your restaurant is mentioned while this phrase is flashed across the television screen, well, it's not quite a laughing matter.

What exactly is slime? It is a type of mold or fungus that accumulates from bacterial growth on surfaces that are constantly exposed to clinging water droplets and warm temperatures. Water residuals may be present on these surfaces due to machine construction or the presence of scouring utensils such as steel wool or scouring pads. If the residuals are left exposed and not wiped clean or the machine is not sanitized regularly, you will then see bacteria and mold growths in the moist, cool environment of your ice machine. Most times, slime will take on a pinkish tone; if left untreated, the pink will turn to red, green, brown and even black ropes of slime hanging from the freezer panels inside the machine after a while. Pretty picture, isn't it?

Slime doesn't exactly cause foodborne illness, but it can cause the ice to have an objectionable taste or odor. Imagine what would happen if one of your customers happens to get a slimy green ice cube in their iced tea -- just don't try telling them that it's St. Patrick's Day in December. More than likely, you'd wind up losing valuable customers at your establishment. People who have sensitive immune systems (such as infants, elderly persons and people with immune deficiencies) are most at risk to diseases passed on through the pathogens found in contaminated ice and other foods, so it's no joke to have slime in the ice machine.

To prevent any potentially embarrassing situations, try keeping the ice machine interior surfaces clean and sanitized using an approved sanitizer as often as twice a week. Take a clean cloth or paper towel, and wipe the condensation from the ice machine surfaces not scoured by ice or water. Follow by wiping the same surface with a clean cloth that moistened with an approved sanitizer and then wrung dry so that it will not drip.

While bleach is a popular and cost-effective sanitizer, it is not safe to use on stainless steel parts. In fact, the chlorine in the bleach reacts with the nickel in the stainless steel, so be careful. The best sanitizer to use is quaternary ammonium (QAC) at 200 parts per million; QAC's have a residual effect which lingers well in ice machines. This chemical should be readily available from your chemical supplier.

Besides working on the ice machine, make sure that your bar guns and soda nozzles are also cleaned, washed and sanitized at the end of the day. Slime can and often will linger in hoses and nozzles that are exposed to moisture and microbes.

By taking the necessary steps for sanitization, you can rest assured that your establishment will not suffer the humiliation of being on the Friday night report as a victim of "slime in the ice machine!"

For more information on this or any other subject, please contact the Bureau of Consumer Health Services at 713-794-9200.

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