Colorado State University Extension
SafeFood Rapid Response Network
SAFEFOOD NEWS - Summer 2000 - Vol 4 / No. 4
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"X" Marks the Rot . . . Or Does It?
There will be a new product available to consumers which provides them with a visual alert to the presence of dangerous bacteria. This product is similar to plastic food wraps now available, but it has the ability to change colors when enough bacterial cells are present to trigger the color change, and possibly a blue "X" in the future, upon further development.
How does this work? The plastic wrap has three microscopic layers, each performing a necessary function. The first layer, which comes in direct contact with the food, has tiny holes that allow bacteria, which may be present on the food, to pass into the second layer.
In the second layer, the bacteria will come into contact with a gel containing antibodies for Salmonella, Campylobacter, E. coli 0157, and Listeria. Attached to the antibodies are tiny, colored plastic beads. The now-colored organism travels towards the third layer of the wrap, where they accumulate and the consumer can tell by a color change that the food is contaminated by bacteria.
At this point it takes between 1,000 and 10,000 bacterial cells to trigger the "X," so there are skeptics to this new product. Michael Doyle, the director of the Center for Food Safety and Quality Enhancement at the University of Georgia, is concerned this type of product may lead to a false sense of security for the consumer. For example, harmful bacteria (E.coli O157) can be present at cell counts well below 1,000 and still lead to foodborne illness if the food is not handled properly.
Toxin Alert, Inc., a Toronto-based company that is developing the Toxin Guard product states that "the message of the product is, if the test is positive, the food is definitely unsafe to eat. But if the test is negative, you should still treat it with some common sense."
Source: New Plastic Food Wrap Changes to Signal Contamination; Question Is, Why? April 18, 2000. National Food Safety Database: Hot Topics.
