There’s good reason the label says “keep refrigerated.” And also good reason not to taste food to see if it’s gone bad.

Two people found that out the hard way, and became very sick with botulism after tasting potato soup left unrefrigerated for weeks, the Centers for Disease Control and Prevention relates in its current Weekly Morbidity and Mortality Report.

In “Notes from the Field,” the CDC tells the cautionary tale of a 29-year-old Ohio resident, who sampled potato soup on Jan. 18 from a “bulging plastic container, noted a bad taste” and discarded the rest.

The soup had been purchased on Dec. 7, 2010 from the refrigerated case at a local grocer, then remained unrefrigerated at home for 42 days, the CDC said.

After 5 days of progressively worsening dizziness, blurred vision, and difficulty swallowing and breathing, the man was hospitalized Jan. 28 and required mechanical ventilation and botulism antitoxin. He remained hospitalized for 57 days and then was moved to a rehabilitation facility because of residual weakness.

On April 3, a 41-year-old Georgia woman tasted potato soup that had been purchased from a local grocery store, the CDC said in its second story. The woman thought the soup tasted sour and threw it away.

Her soup, in a plastic container labeled “keep refrigerated,” had been purchased on March 16 and left unrefrigerated for 18 days.

After four days of dizziness and trouble swallowing, the woman developed respiratory distress, required mechanical ventilation and was given botulism antitoxin. She was hospitalized for 16 days before being transferred to a rehab facility.

These two cases weren’t the first in which improper food storage resulted in botulism. Although botulism is often associated with home canning problems, the CDC said that since 1975, 19 U.S. botulism cases have been linked to commercially produced, chilled foods, implying that in at least some of these cases, consumer carelessness or ignorance was responsible for life-threatening illness.

Labels advising refrigeration might be ignored or not noticed, the CDC noted, and do not warn about the danger of consuming unrefrigerated food. 

The health authority also observed that heating food to a temperature of 185°F (85°C) for 5 minutes inactivates the paralyzing toxin produced by Clostridium botulinum bacteria, so proper preparation also is an important safeguard.