Outbreaks caused by sprouts, United States, 1998-2010: lessons learned and solutions needed.

After a series of outbreaks associated with sprouts in the mid-1990s, the U.S. Food and Drug Administration (FDA) published guidelines in 1999 for sprouts producers to reduce the risk of contamination. The recommendations included treating seeds with an antimicrobial agent such as calcium hypochlorite solution and testing spent irrigation water for pathogens. From 1998 through 2010, 33 outbreaks from seed and bean sprouts were documented in the United States, affecting 1330 reported persons. Twenty-eight outbreaks were caused by Salmonella, four by Shiga toxin-producing Escherichia coli, and one by Listeria. In 15 of the 18 outbreaks with information available, growers had not followed key FDA guidelines. In three outbreaks, however, the implicated sprouts were produced by firms that appeared to have implemented key FDA guidelines. Although seed chlorination, if consistently applied, reduces pathogen burden on sprouts, it does not eliminate the risk of human infection. Further seed and sprouts disinfection technologies, some recently developed, will be needed to enhance sprouts safety and reduce human disease. Improved seed production practices could also decrease pathogen burden but, because seeds are a globally distributed commodity, will require international cooperation.

Geospatial Mapping of Early Cases in Multistate Foodborne Disease Outbreaks: A Strategy To Expedite Identification of Contaminated Imported Produce, United States, 2006 to 2013.

From 1998 to 2008, produce-related illness outbreaks accounted for roughly one-half of reported foodborne outbreaks in the United States. In 2013, Mexico accounted for approximately 50 and 30% of the monetary value of all vegetables and fruits, respectively, imported into the United States. We used historical import data to examine the correlation between the port of entry for five implicated produce vehicles from five multistate outbreaks and the geospatial and temporal distribution of illnesses in the corresponding outbreaks in the United States. For comparison, we analyzed the geospatial and temporal distribution of cases from two U.S. multistate outbreaks associated with domestically grown produce. The geospatial distribution of illnesses in the two outbreaks linked to domestic produce differed from that of the import-related produce outbreaks. The results of our pilot study suggest that geospatial distribution of early-onset cases may be used to identify ports of entry for produce likely to be responsible for causing multistate outbreaks in the United States and that targeted sampling of produce items from these ports of entry may expedite identification of an outbreak vehicle.