The Centers for Disease Control and Prevention (CDC) have issued a report about the 2015 E. coli O157:H7 outbreak linked to a dough mix that was made into pizzas at “restaurant A.” That outbreak sickened at least 13 people in nine states.
On January 4, 2016, PulseNet identified a cluster of 10 Shiga toxin-producing E. coli O157:H7 infections. The dates of illness onset ranged from December 6, 2015 through February 9, 2016. Eventually, 13 outbreak-associated cases were identified in Minnesota (5), Iowa (1), Illinois (1), Kansas (1), North Carolina (1), Nebraska (1), New Jersey (1), South Dakota (1), and Wisconsin (1). Eight of those patients were hospitalized, and two developed hemolytic uremic syndrome (HUS).
Twelve patients were interviewed, and nine reported eating at one of the nine locations of restaurant A the week before they got sick. Eight of those patients ate a specific dessert pizza made with a dough mix provided by “manufacturer A.” The restaurant stopped using the dough mix on February 4, 2016.
Eighty-eight samples of the dry dough mix from five restaurant locations where patients ate were collected by public health officials in Illinois, Iowa, Minnesota, Nebraska, and Wisconsin. The Minnesota Department of Agriculture identified some non-STEC bacteria.
The report states, “Although no laboratory evidence identified contaminated flour as the ultimate source of this STEC O157:H7 outbreak, the identification of other enteric pathogens in multiple samples of dry dough mix consumed by patients associated with the outbreak implicates contaminated flour as the possible source of pathogen introduction for this outbreak. The small number of cases and the lack of additional restaurant clusters suggest that this was a low level contamination event or that contamination only affected a limited amount of product.”
Officials found that the dessert pizzas may have been made with thicker dough that was undercooked in some parts. The flour used to make the dough has been implicated in this outbreak. Flour is a raw agricultural product and does not undergo a kill step when processed, so it can contain pathogenic bacteria.
To prevent E. coli infections, never eat raw or undercooked dough products made with flour. Be careful handling flour, and always wash your hands well after using it. In addition, clean countertops and other surfaces that may have been dusted with flour with soap and water after you are finished in the kitchen.
