The U.S. Centers for Disease Control and Prevention (CDC) issued an alert February 9 after a California couple was hospitalized for more than a week. Stool tests showed evidence of Clostridium botulinum type A, a bacterium that causes a foodborne illness called botulism.

The illness typically occurs from eating contaminated home-canned foods, but also can occur from eating other types of contaminated foods. Symptoms may include facial weakness, slurred speech and the inability to urinate. Patients may also experience muscle weakness that begins in the shoulders, and then moves down the body, causing paralysis. The paralysis can restrict breathing and result in death unless the patient is put on a breathing machine (ventilator). Only about 8 percent of botulism cases end in death, according to the CDC.

The California couple -- a 67-year-old woman and her 75-year-old husband -- routinely prepare their own tofu, also called soybean curd. Tofu, a source of protein, is made from curdled soybean milk.

According to the report, the couple purchased the tofu at a retail market. They took it home and prepared it using a recipe the woman told authorities she has used for decades. It included boiling and marinading the tofu and storing it at room temperature for 10 to 15 days.

Officials are not certain what might have contaminated the tofu. According to the CDC, C. botulinum bacteria spores grow under conditions where temperatures are above 39.2 degrees Fahrenheit, where there is a pH less than 4.6 and where there is no oxygen (anaerobic). The couple's home was between 68 and 77 degrees, there was an almost neutral pH level and they boiled the tofu, creating a potentially anaerobic environment.

The woman began to experience symptoms on November 28, 2006, when she had double vision, followed the next day by sagging drooping eyelids on both sides of her face. Other symptoms included dizziness, difficulty swallowing, slurred speech, drooling and weakness in her right arm. Her husband reported the same symptoms.

On December 5, physicians treating the couple suspected foodborne botulism and alerted local public health authorities, who sent a botulinum antitoxin (antibodies that neutralize the toxins).

Copyright 2007 iVillage Total Health.