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Evaluation of the Appropriateness of Previously Developed Escherichia coli Biotype I Surrogates as Predictors of Non-O157 Shiga-toxin Producing E. coli (STECs) in Beef


Meat and poultry are potential sources of pathogens associated with foodborne illness. The
seriousness of the problem was illustrated with the outbreak of foodborne illness in several western
states in 1992. The outbreak was attributed to undercooked hamburgers contaminated with E. coli
O157:H7 that were served at a fast-food restaurant. This particular outbreak caused hundreds of
illnesses and four deaths. Since then, great efforts from the government, industry and academic
sectors have been made to reduce E. coli O157:H7 contamination and improve meat safety.
Unfortunately, recalls and illnesses continue to be associated with beef products.<P>
Also, there is a growing concern over the risks associated with non-O157 STECs and beef.
Incidence of Foodborne caused illnesses due to STECs have increased over the past decade.
STECs comprise many pathogenic serotypes of which O157:H7 is the most studied. However, the
percentage of non-O157 serotype infections is increasing in many countries. In addition to
O157:H7, the CDC has stated that the serotypes most commonly identified in human illness are
O26, O45, O103, O111, O121, and O145. <P>
Three E. coli biotype I strains previously isolated from cattle hides and determined to be appropriate
for use as surrogates for E. coli O157:H7 based on collaborative studies conducted by Texas A&M
University and Iowa State University. Six non-E. coli O157 STECs serotypes identified as O26,
O111, O121, O145, O103, and O45 were selected as target pathogens for comparison against the
known surrogate bacteria. <P>
Objective : To compare the growth, resistance, and survival properties of non-O157 STECs to those of E. coli
biotype I microorganisms previously identified as E. coli O157:H7 surrogates.

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Ideally, growth characteristics of surrogate organisms should be equivalent or greater but no less
than target pathogens. Growth characteristics for O26 (ATCC 12795), O111 (ATCC 43887), and
O103 (ATCC 23982) were compared to determine if the previously identified E. coli O157:H7
surrogates can also be used for non-O157 STECs. These data demonstrate that the overall growth
characteristics for the E. coli biotype I surrogates and the three non-O157 STECs are similar. <P>

Harris, Kerri; Acuff, Gary
Texas A&M University
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