Lieutenant Commander Rajal Mody, MD, MPH – CDC:

Lesson 1: A sprouted seed is a perfect vehicle for pathogens.

A sprouting seed is as inviting and nourishing as Salmonella or E coli could want, and the warm, moist conditions in which sprouts are produced only make matters worse. A single Salmonella organism on the outside of a seed can easily grow to an infectious dose after it has sprouted. The bacteria in or on growing sprouts cannot be washed off. Because Shiga toxin-producing E coli (STEC) have a low infectious dose, sprouts are a great vehicle. Sprouts have also been the vehicle for Listeria, which causes a very dangerous infection for pregnant women and the elderly.

Lesson 2: Sprouts have caused many outbreaks of illness.

Since sprouts were first recognized as a source of foodborne disease in the mid-1990s, they have become one of the “usual suspects” that foodborne disease epidemiologists look for when investigating an E coli or Salmonella outbreak. Since 1998, more than 30 outbreaks have been reported to the CDC, due to many different kinds of sprouts — alfalfa, bean, clover, and others. In fact, CDC’s foodborne disease surveillance systems have identified 3 sprouts-associated outbreaks since June of 2010 that spread across multiple states.

Lesson 3: It is difficult to grow “safe” sprouts.

Once the potential dangers of sprouts became known, the US Food and Drug Administration developed guidance to help sprout growers reduce the risk for pathogen contamination in sprouts they produce and sell. Many sprouts growers have implemented practices to decontaminate seeds before sprouting, but no available method has proved completely effective. People who eat raw sprouts ought to know that they are taking a risk, including people who grow their own sprouts, because the contamination typically starts with the seed.

Lesson 4: Sprouts can make even young and healthy people ill.

This is one of the biggest lessons learned from the outbreak in Europe in 2011 and from our experience with outbreaks in this country. Sproutbreaks in the United States predominantly affect healthy persons aged 20-49 years. A typical victim may be an especially health conscious person in the prime of life. Nevertheless, illnesses from sprouts can be particularly severe in vulnerable populations, such as young children, older adults, pregnant women, and people with compromised immunity.

Lesson 5: It can be hard for those who become ill to remember having eaten sprouts.

We have found in our investigation of outbreaks that were ultimately linked to sprouts that people often do not remember having eaten them, because they are often just a garnish or just one of many ingredients in a food dish. It is not necessary to eat large quantities of sprouts to make a person sick. An ill person’s inability to accurately recall what they ate sometimes makes it difficult to pinpoint an outbreak of sprouts.