S16: Developments in STEC detection to meet the new regulations

Monday, October 29, 2012: 1:30 PM
Wendy Warren, Aegis Food Testing Laboratories, Inc., North Sioux City, SD
Shiga-toxin producing Escherichia coli (STEC) causing severe and even
fatal foodborne illness have been a focal point for public health
agencies, regulators and food processors for a number of years.  In
particular, E. coli O157:H7 has consistently proven in the U.S. to be
the most concerning STEC strain due to its ability to cause severe
hemolytic uremic syndrome (HUS).  Major advances have been made by the
food processing industry in controlling E. coli
O157:H7 based on verified program adjustments, and thus the overall
number of associated illnesses has decreased.  While E. coli O157:H7
control remains a top priority, additional non-O157 STEC are a more
recent concern due to continued association with foodborne illness.   
Accordingly, this year the USDA-FSIS has declared six strains of STEC
in addition to E. coli O157:H7 as adulterants in raw, non-intact beef.  
While surveillance for and verification of E. coli
O157:H7 control has been successfully conducted based unique
diagnostic features of this strain, the additional, non-O157 STEC
strains lack such features and appear very similar to harmless
bacteria at the molecular level, often resulting in an improper signal
to noise ratio generated by currently available diagnostic
tools.   Consequently, food processors are limited in their ability  
to verify whether assay reactivity is due to pathogenic E. coli or
their benign counterparts.