In 1999, two major events unfolded that raised public awareness of the foodborne illness risk associated with consumption of raw sprouts.
During September 1999, a multistate outbreak of Salmonella serovar Muenchen infection associated with eating raw alfalfa sprouts was identified in Wisconsin. Despite use of a calcium hypochlorite sanitizing procedure to pretreat seeds before sprouting, at least 157 outbreak-related illnesses were identified in seven states involving multiple sprout growers who received alfalfa seed from a specific lot.
That same year, the Food and Drug Administration (FDA) released guidance to help seed producers and sprout growers enhance the safety of their products. Specific measures recommended in the guidelines include a seed disinfection step and microbiologic tests of water that has been used to grow each lot of sprouts. Those recommendations are still in place today.
The current Jimmy John’s clover sprout E. coli O26 outbreak is evidence that more than a decade of special attention to the issue hasn’t eliminated the danger of pathogenic contamination of ready-to-eat raw sprouts — including those served on Jimmy John’s sandwiches in five Midwestern states from late December through January.
The Centers for Disease Control and Prevention (CDC) said two separate sprouting facilities that supplied Jimmy John’s used the same lot of seed to grow clover sprouts served at the restaurant locations where 12 people became sick (including two who were hospitalized.) On February 10, 2012, the seed supplier notified recipients of this lot of clover seed to stop using the seeds and investigations are ongoing to identify where clover sprouts grown from the seed lot were distributed.
Counting the Ways that Seeds go Bad
Experience has taught the industry that sprout seeds might become contaminated in several ways. They could be grown with contaminated water or improperly composted manure fertilizer. They could be contaminated with feces from domestic or wild animals, or with runoff from animal production facilities, or by improperly cleaned growing or processing equipment. Seeds also might become contaminated during harvesting, distribution, or storage.
Many clover seeds are produced for agricultural use, so they might not be processed, handled, and stored as human food would. The warm, moist conditions suitable for sprouting the seed also permit bacteria on seeds to grow and amplify quickly once they are in a growers’ hothouse.
Various seed treatments are in use to address the issue, but the continued occurrence of sprout-related outbreaks despite presprouting disinfection supports the concern that no available treatment will eliminate pathogens from seeds before sprouting.
By the CDC’s own admission, the FDA guidelines for seed suppliers and sprout growers would not have detected the strain of E. coli 026 in the Jimmy John’s outbreak because it is not a pathogen that the agency recommends that growers test for.
The world’s biggest reminder of the health risk associated with eating raw sprouts happened less than a year ago in Germany and other European countries. In that toxic E. coli outbreak more than 50 people died and more than 4,000 were confirmed as infected by the outbreak bacteria. On July 5, 2011, the European Food Safety Authority issued a report identifying a single lot of fenugreek seeds, from an exporter in Egypt, as the culprit.
The only effective way to eliminate risk of food-borne illness from raw sprouts is to avoid eating them. In particular, persons at high risk for severe complications of infection with Salmonella and toxic E. coli, such as the elderly, children, and those with compromised immune systems, have been cautioned for more than a decade not to eat raw sprouts.
