Research Publications (Food Safety)

Cattle are considered to be the main reservoir for Shiga toxin-producing Escherichia coli (STEC) and are often the direct or indirect source of STEC outbreaks in humans. Accurate measurement of the concentration of shed STEC in cattle feces could be a key answer to questions concerning transmission of STEC, contamination sources and efficiency of treatments at farm level.

We investigated the effects of deep-frying or oven cooking on inactivation of Shiga toxin–producing cells of Escherichia coli (STEC) in meatballs. Finely ground veal and/or a finely ground beef-pork-veal mixture were inoculated (ca. 6.5 log CFU/g) with an eight-strain, genetically marked cocktail of rifampin-resistant STEC strains (STEC-8; O111:H, O45:H2, O103:H2, O104:H4, O121:H19, O145:NM, O26:H11, and O157:H7).

Publication date: October 2016
, Volume 68

Author(s): Mastura Akhtar, Alice Maserati, Francisco Diez-Gonzalez, Fernando Sampedro

Publication date: August 2016
, Volume 57

Author(s): Hui Li, Rigoberto Garcia-Hernandez, Darcy Driedger, Lynn M. McMullen, Michael Gänzle

Several antimicrobial compounds are in commercial meat processing plants for pathogen control on beef carcasses. However, the efficacy of the method used is influenced by a number of factors, such as spray pressure, temperature, type of chemical and concentration, exposure time, method of application, equipment design, and the stage in the process that the method is applied.

Shiga toxin–producing Escherichia coli (STEC) strains produce extracellular cellulose and colanic acid, which may influence stress tolerance. This study investigates the role of these extracellular polymers on the tolerance of STEC to chlorine treatment after attachment to lettuce and spinach. Four STEC strains, two wild-type cellulose-producing and their cellulose-deficient derivatives, were used. One strain pair produced colanic acid in addition to cellulose.

Publication date: August 2016
, Volume 118

Author(s): Staci L. DeGeer, Luxin Wang, Gretchen N. Hill, Manpreet Singh, Sacit F. Bilgili, Christy L. Bratcher

Publication date: October 2016
, Volume 68

Author(s): Cangliang Shen, Amanda McKeith, Courtney Broyles, Russell McKeith

Enterotoxigenic Escherichia coli (ETEC) and Shiga toxin-producing E. coli (STEC) are important causes of diarrhea and edema disease in swine. The majority of swine-pathogenic E. coli strains belong to a limited range of O serogroups, including O8, O138, O139, O141, O147, O149, and O157, which are the most frequently reported strains worldwide.

Shiga toxin-producing Escherichia coli O157:H7 (STEC) cause food-borne illness that may be fatal. STEC strains enumerate two types of potent Shiga toxins (Stx1 and Stx2) that are responsible for causing diseases. It is important to detect the E. coli O157 and Shiga toxins in food to prevent outbreak of diseases. We describe the development of two multi-analyte antibody-based lateral flow immunoassays (LFIA); one for the detection of Stx1 and Stx2 and one for the detection of E.

Background: Shiga toxin (Stx) produced by pathogenic Escherichia coli (E. coli) is considered to be an AB5 heterohexamer; however no known mechanisms ensure AB5 assembly.

Results: Stx released by E. coli is not in the AB5 conformation and assembles at receptor interface.

Conclusion: Unassembled Stx can impart toxicity.

Significance: Preventing AB5 assembly is a potential treatment for Stx associated illnesses.

Shiga toxin (Stx)-producing Escherichia coli (STEC) bacteria are foodborne pathogens responsible for diarrhea and hemolytic-uremic syndrome (HUS). Shiga toxin, the main STEC virulence factor, is encoded by the stx gene located in the genome of a bacteriophage inserted into the bacterial chromosome. The O26:H11 serotype is considered to be the second-most-significant HUS-causing serotype worldwide after O157:H7.

Publication date: 15 April 2016
, Volume 186

Author(s): Qiyan Xiong, Jia Wang, Yan Ji, Bo Ni, Bixiong Zhang, Qinghong Ma, Yanna Wei, Shaobo Xiao, Zhixin Feng, Maojun Liu, Guoqing Shao

A culture method to detect non-O157 Shiga toxin–producing Escherichia coli (STEC) was optimized in this study. The finished dairy compost with 30% moisture content was inoculated with a cocktail of six non-O157 STEC serovars at initial concentrations of 1 to 100 CFU/g.

The primary objective of this study was to determine the prevalence and level of enterohemorrhagic Escherichia coli (EHEC) O26, O45, O103, O111, O121, and O145 (collectively EHEC-6) plus EHEC O157 in fecal, hide, and preintervention carcass surface samples from culled dairy cows. Matched samples (n =300) were collected from 100 cows at harvest and tested by a culture-based method and two molecular methods: NeoSEEK STEC (NS) and Atlas STEC EG2 Combo.

Publication date: September 2016
, Volume 67

Author(s): A. Gunvig, C. Borggaard, F. Hansen, T.B. Hansen, S. Aabo

Publication date: Available online 22 February 2016


Author(s): L. Pianciola, B.A. D’Astek, M. Mazzeo, I. Chinen, M. Masana, M. Rivas

Publication date: June 2016
, Volume 116

Author(s): S. Pokharel, J.C. Brooks, J.N. Martin, A. Echeverry, A.R. Parks, B. Corliss, M.M. Brashears

Escherichia coli O111 is an emerging non-O157:H7 serotype of Shiga toxin-producing E. coli (STEC). We previously reported that outbreak and environmental, but not sporadic-case, strains of STEC O111 share a distinct aggregation phenotype (M. E. Diodati, A. H. Bates, M. B. Cooley, S. Walker, R. E. Mandrell, and M. T. Brandl, Foodborne Pathog Dis 12:235–243, 2015, http://dx.doi.org/10.1089/fpd.2014.1887).

Raies A. Mir, Thomas A. Weppelmann, Mauricio Elzo, Soohyoun Ahn, J. Danny Driver, KwangCheol Casey Jeong

Shiga toxin-producing Escherichia coli (STEC) serotype O145 is one of the major non-O157 serotypes associated with severe human disease. Here we examined the genetic diversity, population structure, virulence potential, and antimicrobial resistance profiles of environmental O145 strains recovered from a major produce production region in California.

The increased summertime prevalence of cattle carriage of enterohemorrhagic Shiga toxin-producing Escherichia coli O157:H7 (STEC O157) is associated with the increased summertime incidence of human infection. The mechanism driving the seasonality of STEC O157 carriage among cattle is unknown. We conducted experimental challenge trials to distinguish whether factors extrinsic or intrinsic to cattle underlie the seasonality of STEC O157 colonization.

Publication date: 16 February 2016
, Volume 219

Author(s): Bavo Verhaegen, Inge Van Damme, Marc Heyndrickx, Nadine Botteldoorn, Mohamed Elhadidy, Karen Verstraete, Katelijne Dierick, Sarah Denayer, Lieven De Zutter, Koen De Reu

Enterohemorrhagic Escherichia coli (EHEC) O26:H11, a serotype within Shiga toxin-producing E. coli (STEC) that causes severe human disease, has been considered to have evolved from attaching and effacing E. coli (AEEC) O26:H11 through the acquisition of a Shiga toxin-encoding gene.

Publication date: May 2016
, Volume 63

Author(s): Christopher A. Baker, Si Hong Park, Sun Ae Kim, Peter M. Rubinelli, Stephanie M. Roto, Sang In Lee, Shawn Ramsaroop, Melinda Miller, Steven C. Ricke