Mathematical Modeling of Growth of Non-O157 Shiga Toxin-Producing Escherichia coli in Raw Ground Beef

2012 ◽  
Vol 77 (4) ◽  
pp. M217-M225 ◽  
Author(s):  
Lihan Huang ◽  
Shu-I Tu ◽  
John Phillips ◽  
Pina Fratamico
Keyword(s):  
Mathematical Modeling ◽  
Escherichia Coli ◽  
Shiga Toxin ◽  
Ground Beef

Survival comparison of Shiga toxin producing Escherichia coli (STEC) O26 and farm isolated O26 in ground beef

Meat Science ◽  
2014 ◽  
Vol 96 (1) ◽  
pp. 486
Author(s):  
C. Palmer ◽  
C. Bratcher ◽  
M. Singh ◽  
L. Wang
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Ground Beef

Low Prevalence of Salmonella and Shiga Toxin–Producing Escherichia coli in Lymph Nodes of Australian Beef Cattle

2017 ◽  
Vol 80 (12) ◽  
pp. 2105-2111 ◽  
Author(s):  
Gavin Bailey ◽  
Long Huynh ◽  
Lachlan Govenlock ◽  
David Jordan ◽  
Ian Jenson
Keyword(s):  
Escherichia Coli ◽  
Lymph Nodes ◽  
Shiga Toxin ◽  
Limit Of Detection ◽  
Ground Beef ◽  
Plate Count ◽  
Salmonella Spp ◽  
Live Animal ◽  
E Coli ◽  
Low Prevalence

ABSTRACT Salmonella contamination of ground beef has been viewed as originating from the surface of carcasses. Recent studies have identified lymph nodes as a potential source of Salmonella contamination because these tissues play an active role in containment of pathogens in the live animal and because some lymph nodes are unavoidably present in manufacturing beef trimmings or primal cuts that may be incorporated into ground beef. A survey was conducted of the microbiological status of lymph nodes from Australian cattle at the time of slaughter to determine the prevalence of microbiological contamination. Sets of lymph nodes (n = 197), consisting of the superficial cervical (prescapular), prepectoral, axillary, presternal, popliteal, ischiatic, subiliac (precrural), coxalis, and iliofemoralis (deep inguinal), were collected from five geographically separated Australian abattoirs over a period of 14 months. Samples were tested for the presence of Salmonella spp. and Shiga toxin–producing Escherichia coli by BAX PCR assay. Aerobic plate count, E. coli, and coliforms were enumerated with a lower limit of detection of 80 CFU per node. The observed prevalence of Salmonella within peripheral lymph nodes was 0.48% (7 of 1,464). Two of the seven lymph nodes in which Salmonella organisms were detected came from the same animal. Grass-fed, grain-fed, and cull dairy cattle were all found to have detectable Salmonella in lymph nodes. All Salmonella detections occurred during cooler months of the year. No Shiga toxin–producing E. coli were detected. Aerobic microorganisms were detected above the limit of quantification in 3.2% of nodes (median count 2.24 log per node), and E. coli was detected in 0.8% of nodes (median count 3.05 log per node). The low prevalence of Salmonella and low concentration of aerobic microorganisms in Salmonella-positive lymph nodes of Australian cattle at the time of slaughter suggest that the likelihood of lymph nodes contributing significantly to the presence of Salmonella in ground beef is low.

scholarly journals Predicting the Presence of Non-O157 Shiga Toxin-Producing Escherichia coli in Ground Beef by Using Molecular Tests for Shiga Toxins, Intimin, and O Serogroups

2012 ◽  
Vol 78 (19) ◽  
pp. 7152-7155 ◽  
Author(s):  
Joseph M. Bosilevac ◽  
Mohammad Koohmaraie
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Ground Beef ◽  
Content Type ◽  
Shiga Toxins ◽  
Molecular Tests

ABSTRACTWhen 3,972 ground beef enrichments with 6 confirmed to contain a non-O157 Shiga toxin-producing intimin-positiveEscherichia coliisolate were tested for Shiga toxin, intimin, and O group (O26, O45, O103, O111, O121, and O145) genes, 183 potential positives and only 2 of the 6 confirmed positives were identified.

Inactivation of Shiga Toxin–Producing Escherichia coli and Listeria monocytogenes within Plant versus Beef Burgers in Response to High Pressure Processing

2020 ◽  
Vol 83 (5) ◽  
pp. 865-873
Author(s):  
ANNA C. S. PORTO-FETT ◽  
LAURA E. SHANE ◽  
BRADLEY A. SHOYER ◽  
MANUELA OSORIA ◽  
YANGJIN JUNG ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
High Pressure ◽  
Listeria Monocytogenes ◽  
Shiga Toxin ◽  
Ground Beef ◽  
High Pressure Processing ◽  
Empirical Observation ◽  
Beef Burger ◽  
Beef Burgers

ABSTRACT We evaluated high pressure processing to lower levels of Shiga toxin–producing Escherichia coli (STEC) and Listeria monocytogenes inoculated into samples of plant or beef burgers. Multistrain cocktails of STEC and L. monocytogenes were separately inoculated (∼7.0 log CFU/g) into plant burgers or ground beef. Refrigerated (i.e., 4°C) or frozen (i.e., −20°C) samples (25 g each) were subsequently exposed to 350 MPa for up to 9 or 18 min or 600 MPa for up to 4.5 or 12 min. When refrigerated plant or beef burger samples were treated at 350 MPa for up to 9 min, levels of STEC were reduced by ca. 0.7 to 1.3 log CFU/g. However, when refrigerated plant or beef burger samples were treated at 350 MPa for up to 9 min, levels of L. monocytogenes remained relatively unchanged (ca. ≤0.3-log CFU/g decrease) in plant burger samples but were reduced by ca. 0.3 to 2.0 log CFU/g in ground beef. When refrigerated plant or beef burger samples were treated at 600 MPa for up to 4.5 min, levels of STEC and L. monocytogenes were reduced by ca. 0.7 to 4.1 and ca. 0.3 to 5.6 log CFU/g, respectively. Similarly, when frozen plant and beef burger samples were treated at 350 MPa up to 18 min, reductions of ca. 1.7 to 3.6 and ca. 0.6 to 3.6 log CFU/g in STEC and L. monocytogenes numbers, respectively, were observed. Exposure of frozen plant or beef burger samples to 600 MPa for up to 12 min resulted in reductions of ca. 2.4 to 4.4 and ca. 1.8 to 3.4 log CFU/g in levels of STEC and L. monocytogenes, respectively. Via empirical observation, pressurization did not adversely affect the color of plant burger samples, whereas appreciable changes in color were observed in pressurized ground beef. These data confirm that time and pressure levels already validated for control of STEC and L. monocytogenes in ground beef will likely be equally effective toward these same pathogens in plant burgers without causing untoward effects on product color. HIGHLIGHTS

Performance of Chromogenic Agar Media for Isolation of Shiga Toxin–Producing Escherichia coli from Ground Beef

2020 ◽  
Vol 83 (7) ◽  
pp. 1149-1154
Author(s):  
GENTRY L. LEWIS ◽  
NATALIA CERNICCHIARO ◽  
RODNEY A. MOXLEY
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Culture Media ◽  
Geometric Mean ◽  
Ground Beef ◽  
Immunomagnetic Separation ◽  
Broth Culture ◽  
True Negative ◽  
Chromogenic Agar ◽  
Agar Media

ABSTRACT The performance of three chromogenic agar media for detection of the “top seven” Shiga toxin–producing Escherichia coli (STEC) in beef was compared. Samples of retail ground beef were inoculated with STEC O26, O45, O103, O111, O121, O145, or O157 at geometric mean (±standard error of the mean) levels of 0, 48 (±1), 420 (±1), 4,100 (±1), or 45,000 (±1) CFU/10 g and enriched 1:10 (90 mL) in EC broth (40°C for 6 h). Following enrichment, aliquots of broth culture were treated by immunomagnetic separation with one of three pools of beads against the seven STEC serogroups: pool I, O26, O45, and O121; pool II, O103, O111, and O145; and pool III, O157. After immunomagnetic separation, 50 μL of washed bead suspensions in buffered peptone water were spiral plated onto modified Rainbow Agar O157 (mRBA), CHROMagar STEC (CS), or modified Possé differential medium (mPossé2) and incubated at 37°C for 18 h. Up to six isolated colonies were picked from each spiral plate based on expected colony phenotypes for STEC on the respective media, and isolate identity was confirmed with an 11-plex PCR assay targeting the O serogroups and virulence genes. Overall, mRBA had the highest sensitivity (99.2%), correctly detecting a significantly higher proportion of STEC serogroups than either CS (79.4%; P < 0.05) or mPossé2 (91.7%; P < 0.05). mRBA also had the highest negative predictive value (90.0%), correctly identifying a significantly higher proportion of true-negative samples compared with CS (25.7%; P < 0.05) and mPossé2 (46.2%; P < 0.05). However, mRBA also had the lowest analytical specificity of 83.2% (P < 0.05), yielding the lowest proportion of colonies tested that were STEC positive (3,548 of 4,263) compared with 97.7% (3,607 of 3,693) for mPossé2 and 98.0% (2,875 of 2,935) for CS. Reduced specificity results in more work and higher expense due to the increased number of colonies that must be tested. Further improvements in agar culture media for non-O157 STEC isolation are needed. HIGHLIGHTS

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