Federal officials have been unable to determine the specific product implicated in an E. Coli outbreak linked to cake mixes and have declared the outbreak over.

The investigation into the outbreak is also over, according to an update from the Centers for Disease Control and Prevention. The Food and Drug Administration worked on traceback, but could not identify a specific flavor or brand of cake mix as the source of the pathogen. No recalls were initiated in relation to the outbreak.

The outbreak sickened at least 16 people across 12 states. The E. Coli involved was particularly virulent with almost half — seven — of the known patients so sick they had to be admitted to hospitals.

Illnesses started on dates ranging from Feb. 26 to June 21, 2021. The sick people ranged in age from 2 to 73 years old, with a median age of 13, and 100 percent were female. One person developed a type of kidney failure called hemolytic uremic syndrome (HUS). No deaths were reported.

The true number of sick people in an outbreak is likely much higher than the number reported, and the outbreak may not be limited to the states with known illnesses. This is because many people recover without medical care and are not tested for E. coli.

State and local public health officials interviewed people about the foods they ate in the week before they got sick. Of the eight outbreak patients interviewed, six reported tasting or eating raw batter made with a cake mix. People reported buying different varieties and brands of cake mix.

Public health investigators used the PulseNet system to identify outbreak illnesses. Whole Genome Sequencing (WGS) showed that bacteria from sick people’s samples was closely related genetically. This means that people in this outbreak likely got sick from the same food.

The CDC advises people not to eat raw batter of any kind. Eating raw batter can make you sick because some raw ingredients such as flour and eggs can be contaminated with bacteria. Bacteria are killed only when raw batter is baked or cooked.

About E. coli infections

Anyone who has eaten any raw batter of any kind and developed symptoms of E. coli infection should seek medical attention and tell their doctor about their possible exposure to the bacteria. Specific tests are required to diagnose the infections, which can mimic other illnesses.

The symptoms of E. coli infections vary for each person but often include severe stomach cramps and diarrhea, which is often bloody. Some patients may also have a fever. Most patients recover within five to seven days. Others can develop severe or life-threatening symptoms and complications, according to the Centers for Disease Control and Prevention (CDC).

About 5 to 10 percent of those diagnosed with E. coli infections develop a potentially life-threatening kidney failure complication, known as a hemolytic uremic syndrome (HUS). Symptoms of HUS include fever, abdominal pain, feeling very tired, decreased frequency of urination, small unexplained bruises or bleeding, and pallor.

Many people with HUS recover within a few weeks, but some suffer permanent injuries or death. This condition can occur among people of any age but is most common in children younger than five years old because of their immature immune systems, older adults because of deteriorating immune systems, and people with compromised immune systems such as cancer patients.

People who experience HUS symptoms should immediately seek emergency medical care. People with HUS will likely be hospitalized because the condition can cause other serious and ongoing problems such as hypertension, chronic kidney disease, brain damage, and neurologic problems.

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