If you have seen the “danger zone” for food given as two different ranges: 40 degrees to 140 degrees and more recently 41-135 degrees, don’t be confused. What’s most important to remember is the simple notion behind it: Keep hot foods hot and cold foods cold.

The “danger zone” concept indicates that foods within the temperature range are susceptible to growth of bacteria and production of toxins, and can be dangerous if held in that range too long. For years, the zone was marked by 40 degrees Fahrenheit at the bottom end and 140 degrees at the top.

However, more recent research and experience shows that the danger zone is a bit narrower than we thought. As long as foods are kept colder than 41 degrees or hotter than 135 degrees, they’re deemed to be safe. So, in 2009 the Food and Drug Administration amended its Food Code to address the issue. Curriculums for food service training have also adopted the change, as has the Ohio Food Code.

Still, the U.S. Department of Agriculture’s Food Safety and Inspection Service (FSIS) will keep using the old range of 40-140 in its educational materials for consumers. Why? Well, for all practical purposes in the home kitchen, the new range of 41-135 degrees and the old range of 40-140 degrees just aren’t that different from each other. Plus, it’s easier to remember “40-140” than “41-135.” And finally, the FSIS likes to err on the side of caution when it comes to its consumer advice, mostly because it assumes home kitchens have fewer technical controls for food safety than commercial kitchens (which follow the official food codes and are inspected by local departments of health).

Luckily, the food-borne illnesses usually associated with inadequate holding temperatures are usually relatively mild. A 2001 study in the Journal of Nutrition Education estimated that less than a half-million of the 76 million annual cases of food-borne illness are caused by the three pathogens usually associated with the danger zone: Staphylococcus aureus, Clostridium perfringens, and Bacillus cereus.

Still, don’t fall into the trap of believing that reheating foods kept in the danger zone for too long will prevent illness. Some toxins, such as those produced by Staphylococcus aureus, are heat-stable and may never be destroyed even if the food is boiled for 10 hours. That’s why it’s important to remember another old saying: “When in doubt, throw it out.”

This article originally appeared in Chow Line (4/24/05), a service of Ohio State University Extension and the Ohio Agricultural Research and Development Center, and was adapted for use on NetWellness with permission, 2009.

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