Antimicrobial Efficacy of a Lactic Acid and Citric Acid Blend against Shiga Toxin–Producing Escherichia coli, Salmonella, and Nonpathogenic Escherichia coli Biotype I on Inoculated Prerigor Beef Carcass Surface Tissue

2015 ◽  
Vol 78 (12) ◽  
pp. 2136-2142 ◽  
Author(s):  
BRITTNEY R. SCOTT ◽  
XIANG YANG ◽  
IFIGENIA GEORNARAS ◽  
ROBERT J. DELMORE ◽  
DALE R. WOERNER ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Lactic Acid ◽  
Citric Acid ◽  
Shiga Toxin ◽  
Hot Water ◽  
Antimicrobial Efficacy ◽  
Solution Temperature ◽  
Meat Industry ◽  
E Coli ◽  
Beef Carcass

Studies were conducted to (i) determine whether inoculants of nonpathogenic Escherichia coli biotype I effectively served as surrogates for E. coli O157:H7, non-O157 Shiga toxin–producing E. coli, and Salmonella when prerigor beef carcass tissue was treated with a commercially available blend of lactic acid and citric acid (LCA) at a range of industry conditions of concentration, temperature, and pressure; (ii) determine the antimicrobial efficacy of LCA; and (iii) investigate the use of surrogates to validate a hot water and LCA sequential treatment as a carcass spray intervention in a commercial beef harvest plant. In an initial laboratory study, beef brisket tissue samples were left uninoculated or were inoculated (~6 log CFU/cm2) on the adipose side with E. coli O157:H7 (5-strain mixture), non-O157 Shiga toxin–producing E. coli (12-strain mixture), Salmonella (6-strain mixture), or nonpathogenic E. coli (5-strain mixture). Samples were left untreated (control) or were treated with LCA, in a spray cabinet, at one of eight combinations of solution concentration (1.9 and 2.5%), solution temperature (43 and 60°C), and application pressure (15 and 30 lb/in2). In a second study, the E. coli surrogates were inoculated (~6 log CFU/cm2) on beef carcasses in a commercial facility to validate the use of a hot water treatment (92.2 to 92.8°C, 13 to 15 lb/in2) followed by an LCA treatment (1.9%, 50 to 51.7°C, 13 to 15 lb/in2, 10 s). In the in vitro study, surrogate and pathogen bacteria did not differ in their response to the tested LCA treatments. Treatment with LCA reduced (P < 0.05) inoculated populations by 0.9 to 1.5 log CFU/cm2, irrespective of inoculum type. The hot water and LCA sequential treatments evaluated in the commercial facility reduced (P < 0.05) the inoculated nonpathogenic E. coli surrogates on carcasses by 3.7 log CFU/cm2. This study therefore provides the meat industry with data for this sequential multiple hurdle system for the operation parameters described.

scholarly journals Evaluation of Commonly Used Antimicrobial Interventions for Fresh Beef Inoculated with Shiga Toxin–Producing Escherichia coli Serotypes O26, O45, O103, O111, O121, O145, and O157:H7†

2012 ◽  
Vol 75 (7) ◽  
pp. 1207-1212 ◽  
Author(s):  
NORASAK KALCHAYANAND ◽  
TERRANCE M. ARTHUR ◽  
JOSEPH M. BOSILEVAC ◽  
JOHN W. SCHMIDT ◽  
RONG WANG ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Lactic Acid ◽  
Shiga Toxin ◽  
Hot Water ◽  
Sodium Chlorite ◽  
Meat Industry ◽  
Peroxyacetic Acid ◽  
E Coli ◽  
Low Level ◽  
Antimicrobial Interventions

Although numerous antimicrobial interventions targeting Escherichia coli O157:H7 have been developed and implemented to decontaminate meat and meat products during the harvesting process, the information on efficacy of these interventions against the so-called Big Six non-O157 Shiga toxin–producing E. coli (STEC) strains is limited. Prerigor beef flanks (160) were inoculated to determine if antimicrobial interventions currently used by the meat industry have a similar effect in reducing non-O157 STEC serogroups O26, O45, O103, O111, O121, and O145 compared with E. coli O157:H7. A high (104 CFU/cm2) or a low (101 CFU/cm2) inoculation of two cocktail mixtures was applied to surfaces of fresh beef. Cocktail mixture 1 was composed of O26, O103, O111, O145, and O157, while cocktail mixture 2 was composed of O45, O121, and O157. The inoculated fresh beef flanks were subjected to spray treatments by the following four antimicrobial compounds: acidified sodium chlorite, peroxyacetic acid, lactic acid, and hot water. High-level inoculation samples were enumerated for the remaining bacteria populations after each treatment and compared with the untreated controls, while low-level inoculation samples were chilled for 48 h at 4°C before enrichment, immunomagnetic separation, and isolation. Spray treatments with hot water were the most effective, resulting in mean pathogen reductions of 3.2 to 4.2 log CFU/cm2, followed by lactic acid. Hot water and lactic acid also were the most effective interventions with the low-level inoculation on surfaces of fresh beef flanks after chilling. Peroxyacetic acid had an intermediate effect, while acidified sodium chlorite was the least effective in reducing STEC levels immediately after treatment. Results indicate that the reduction of non-O157 STEC by antimicrobial interventions on fresh beef surfaces were at least as great as for E. coli O157:H7. However, the recovery of these low inoculation levels of pathogens indicated that there is no single intervention to eliminate them.

Validation of a Sequential Hide-On Bob Veal Carcass Antimicrobial Intervention Composed of a Hot Water Wash and Lactic Acid Spray in Combination with Scalding To Control Shiga Toxin–Producing Escherichia coli Surrogates†

2018 ◽  
Vol 81 (5) ◽  
pp. 762-768
Author(s):  
JOSHUA D. HASTY ◽  
JOHN A. HENSON ◽  
GARY R. ACUFF ◽  
DENNIS E. BURSON ◽  
JOHN B. LUCHANSKY ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Lactic Acid ◽  
Ambient Temperature ◽  
Shiga Toxin ◽  
Hot Water ◽  
E Coli ◽  
Chemical Agents ◽  
Antimicrobial Interventions ◽  
Antimicrobial Intervention ◽  
Additional Reduction

ABSTRACT Scalding of hide-on bob veal carcasses with or without standard scalding chemical agents typically used for hogs, followed by an 82.2°C hot water wash and lactic acid spray (applied at ambient temperature) before chilling, was evaluated to determine its effectiveness in reducing Shiga toxin–producing Escherichia coli surrogate populations. A five-strain cocktail of rifampin-resistant, nonpathogenic E. coli surrogates was used to inoculate hides of veal carcasses immediately after exsanguination (target inoculation level of 7.0 log CFU/100 cm2). For carcasses receiving no scalding treatments, spraying with 82.2°C water as a final wash resulted in a 4.5-log CFU/100 cm2 surrogate reduction, and an additional 1.2-log CFU/100 cm2 reduction was achieved by spraying with 4.5% lactic acid before chilling. Scalding hide-on carcasses in 60°C water (no chemicals added) for 4 min in a traditional hog scalding tank resulted in a 2.1-log CFU/100 cm2 reduction in surrogate levels, and a subsequent preevisceration 82.2°C water wash provided an additional 2.9-log CFU/100 cm2 reduction. Spraying a 4.5% solution of lactic acid onto scalded, hide-on carcasses (after the 82.2°C water wash) resulted in a minimal additional reduction of 0.4 log CFU/100 cm2. Incorporation of scalding chemicals into the scald water resulted in a 4.1-log CFU/100 cm2 reduction (1.9 log CFU/100 cm2 greater than scalding without chemicals) in the surrogate population, and the first 82.2°C wash provided an additional 2.5-log CFU/100 cm2 reduction. Application of antimicrobial interventions did not affect the carcass temperature decline during chilling, the pH decline, or the color characteristics of the ribeye or the flank of the bob veal carcasses.

Validation of commonly used antimicrobial interventions on bob veal carcasses for reducing Shiga toxin producing Escherichia coli surrogate populations

2021 ◽  
Author(s):  
Chevise L. Thomas ◽  
Harshavardhan Thippareddi ◽  
Sanjay Kumar ◽  
Macc Rigdon ◽  
Robert W. Mckee ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Lactic Acid ◽  
Shiga Toxin ◽  
Hot Water ◽  
Peroxyacetic Acid ◽  
E Coli ◽  
Translocation Experiment ◽  
Low Levels ◽  
Antimicrobial Interventions ◽  
Antimicrobial Treatments

Ruminants are natural reservoirs of Shiga toxin producing Escherichia coli (STEC), and the STEC can be easily transferred to carcasses during the conversion of animals to meat. Three experiments were conducted to validate the efficacy of lactic acid (4%; LA), peroxyacetic acid (300 ppm; PAA), and hot water (80˚C; HW) for their individual or combined abilities to reduce STEC surrogates on bob veal carcasses pre- and post-chill and through fabrication. In experiment 1, hot carcasses (n=9) were inoculated with a 5-strain cocktail (ca. 8 log CFU/mL) containing rifampicin-resistant surrogate Escherichia coli ( E. coli ; BAA-1427, BAA-1428, BAA-1429, BAA-1430, and BAA-1431) and then treated with HW, LA, or PAA. Carcasses were then chilled (0±1°C; 24 h), split in half, and each side was treated with either LA or PAA. In experiment 2, hot carcasses (n=3) were inoculated and chilled (24 h). After 24 h, the carcasses were split, and each side was treated with either LA or PAA. For experiment 3, carcasses (n=3) were chilled for 24 h, split, inoculated, and treated with either LA or PAA. After chilling, carcasses from all three experiments were fabricated to subprimals and the cut surfaces were sampled to determine the translocation. Experiment 1 showed that LA+LA was the most effective ( P ≤ 0.05) treatment for reducing surrogate E. coli on veal. In experiments 2 and 3, LA and PAA were similar ( P > 0.05) in their abilities to reduce E. coli on chilled veal carcasses. In experiments 1 and 2, all antimicrobial treatments resulted in undetectable levels (< 0.2 log CFU/cm 2 ) of surrogate E. coli on cut surfaces after fabrication, while low levels (1.7 and 1.0 log CFU/cm 2 for LA and PAA, respectively) were observed in experiment 3. Of the antimicrobial interventions utilized, lactic acid was more effective for reducing STEC surrogate populations on veal carcasses, pre- and/or post-chill.

Interventions for the Reduction of Salmonella Typhimurium DT 104 and Non-O157:H7 Enterohemorrhagic Escherichia coli on Beef Surfaces†

2000 ◽  
Vol 63 (10) ◽  
pp. 1326-1332 ◽  
Author(s):  
CATHERINE N. CUTTER ◽  
MILDRED RIVERA-BETANCOURT
Keyword(s):  
Escherichia Coli ◽  
Acetic Acid ◽  
Lactic Acid ◽  
Salmonella Typhimurium ◽  
Enterohemorrhagic Escherichia Coli ◽  
Hot Water ◽  
Trisodium Phosphate ◽  
Meat Industry ◽  
E Coli

A study was conducted to determine if slaughter interventions currently used by the meat industry are effective against Salmonella Typhimurium definitive type 104 (DT 104) and two non-O157:H7 enterohemorrhagic Escherichia coli (EHEC). Three separate experiments were conducted by inoculating prerigor beef surfaces with a bovine fecal slurry containing Salmonella Typhimurium and Salmonella Typhimurium DT 104 (experiment 1), E. coli O157:H7 and E. coli O111:H8 (experiment 2), or E. coli O157:H7 and E. coli O26:H11 (experiment 3) and spray washing with water, hot water (72°C), 2% acetic acid, 2% lactic acid, or 10% trisodium phosphate (15 s, 125 ± 5 psi, 35 ± 2°C). Remaining bacterial populations were determined immediately after treatments (day 0), after 2 days of aerobic storage at 4°C, and after 7, 21, and 35 days of vacuum-packaged storage at 4°C. In addition to enumeration, confirmation of pathogen serotypes was performed for all treatments on all days. Of the interventions investigated, spray treatments with trisodium phosphate were the most effective, resulting in pathogen reductions of >3 log10 CFU/cm2, followed by 2% lactic acid and 2% acetic acid (>2 log10 CFU/cm2). Results also indicated that interventions used to reduce Salmonella Typhimurium on beef surfaces were equally effective against Salmonella Typhimurium DT 104 immediately after treatment and again after long-term, refrigerated, vacuum-packaged storage. Similarly, E. coli O111:H8 and E. coli O26:H11 associated with beef surfaces were reduced by the interventions to approximately the same extent as E. coli O157:H7 immediately after treatment and again after long-term, refrigerated, vacuum-packaged storage. It was also demonstrated that phenotypic characterization may not be sufficient to identify EHECs and that the organisms should be further confirmed with antibody- or genetic-based techniques. Based on these findings, interventions used by the meat industry to reduce Salmonella spp. and E. coli O157:H7 appear to be effective against DT 104 and other EHEC.

Evaluation of Lactic Acid as an Initial and Secondary Subprimal Intervention for Escherichia coli O157:H7, Non-O157 Shiga Toxin–Producing E. coli, and a Nonpathogenic E. coli Surrogate for E. coli O157:H7

2012 ◽  
Vol 75 (9) ◽  
pp. 1701-1708 ◽  
Author(s):  
C. I. PITTMAN ◽  
I. GEORNARAS ◽  
D. R. WOERNER ◽  
K. K. NIGHTINGALE ◽  
J. N. SOFOS ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Lactic Acid ◽  
Shiga Toxin ◽  
Hazard Analysis ◽  
Control Point ◽  
Escherichia Coli O157 ◽  
Meat Industry ◽  
Bacterial Reduction ◽  
E Coli ◽  
Critical Control Point

Lactic acid can reduce microbial contamination on beef carcass surfaces when used as a food safety intervention, but effectiveness when applied to the surface of chilled beef subprimal sections is not well documented. Studies characterizing bacterial reduction on subprimals after lactic acid treatment would be useful for validations of hazard analysis critical control point (HACCP) systems. The objective of this study was to validate initial use of lactic acid as a subprimal intervention during beef fabrication followed by a secondary application to vacuum-packaged product that was applied at industry operating parameters. Chilled beef subprimal sections (100 cm2) were either left uninoculated or were inoculated with 6 log CFU/cm2 of a 5-strain mixture of Escherichia coli O157:H7, a 12-strain mixture of non-O157 Shiga toxin–producing E. coli (STEC), or a 5-strain mixture of nonpathogenic (biotype I) E. coli that are considered surrogates for E. coli O157:H7. Uninoculated and inoculated subprimal sections received only an initial or an initial and a second “rework” application of lactic acid in a custom-built spray cabinet at 1 of 16 application parameters. After the initial spray, total inoculum counts were reduced from 6.0 log CFU/cm2 to 3.6, 4.4, and 4.4 log CFU/cm2 for the E. coli surrogates, E. coli O157:H7, and non-O157 STEC inoculation groups, respectively. After the second (rework) application, total inoculum counts were 2.6, 3.2, and 3.6 log CFU/cm2 for the E. coli surrogates, E. coli O157:H7, and non-O157 STEC inoculation groups, respectively. Both the initial and secondary lactic acid treatments effectively reduced counts of pathogenic and nonpathogenic strains of E. coli and natural microflora on beef subprimals. These data will be useful to the meat industry as part of the HACCP validation process.

Identification of Escherichia coli O157:H7 Surrogate Organisms To Evaluate Beef Carcass Intervention Treatment Efficacy

2010 ◽  
Vol 73 (10) ◽  
pp. 1864-1874 ◽  
Author(s):  
STEVEN C. INGHAM ◽  
RYAN J. ALGINO ◽  
BARBARA H. INGHAM ◽  
RONALD F. SCHELL
Keyword(s):  
Escherichia Coli ◽  
Acetic Acid ◽  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Treatment Efficacy ◽  
Acid Treatment ◽  
Starter Culture ◽  
Hot Water ◽  
E Coli ◽  
Beef Carcass

We compared the survival of potential pathogen surrogates—meat-hygiene indicators (non–Escherichia coli coliforms), biotype I E. coli, and lactic acid bacteria starter cultures—with survival of an E. coli O157:H7 (ECO157:H7) inoculum in beef carcass intervention trials. Survival of one lactic acid bacteria starter culture (Bactoferm LHP Dry [Pediococcus acidilactici and Pediococcus pentosaceus]), a five-isolate biotype I inoculum, and a five-isolate non–E. coli coliform inoculum, was compared with survival of a 12-isolate ECO157:H7 inoculum in interventions by using beef brisket (adipose and lean), cod fat membrane, or neck tissue. Treatments were grouped by abattoir size: small (6-day dry aging; 22°C acid treatment [2.5% acetic acid, 2% lactic acid, or Fresh Bloom], followed by 1-day dry aging; hot water) and large (warm acid treatment [5% acetic acid or 2% lactic acid] with or without a preceding hot water treatment). Reductions in pathogen and surrogate inocula were determined with excision sampling. A surrogate was considered a suitable replacement for ECO157:H7 if the intervention produced a reduction in surrogate levels that was not significantly greater (P ≥ 0.05) than that observed for ECO157:H7. All three surrogate inocula were suitable as ECO157 surrogates for dry aging and acid spray plus dry-aging treatments used by small abattoirs. No one inoculum was suitable as an ECO157 surrogate across all intervention treatments used by large abattoirs. Effects seen on neck tissue were representative of other tissues, and the low value of the neck supports its use as the location for evaluating treatment efficacy in in-plant trials. Results support using nonpathogenic surrogate organisms to validate beef carcass intervention efficacy.

Fluorescent Protein–Marked Escherichia coli Biotype I Strains as Surrogates for Enteric Pathogens in Validation of Beef Carcass Interventions

2009 ◽  
Vol 72 (2) ◽  
pp. 295-303 ◽  
Author(s):  
ELISA CABRERA-DIAZ ◽  
TIFFANY M. MOSELEY ◽  
LISA M. LUCIA ◽  
JAMES S. DICKSON ◽  
ALEJANDRO CASTILLO ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Lactic Acid ◽  
Fluorescent Protein ◽  
Cell Surface Hydrophobicity ◽  
Hot Water ◽  
Enteric Pathogens ◽  
E Coli ◽  
Beef Carcasses ◽  
Phosphate Buffered Saline ◽  
Beef Carcass

The efficacy of antimicrobial interventions implemented in slaughter establishments to reduce enteric pathogens on beef carcasses should optimally be validated under commercial operation conditions. This study was conducted to identify surrogate organisms for enteric pathogens that could be used to validate beef carcass interventions. The growth, resistance, and attachment properties of nonpathogenic fluorescent protein–marked Escherichia coli strains were compared with those of E. coli O157: H7 and Salmonella strains. Growth curves were obtained based on growth in tryptic soy broth at 37°C. In general, growth parameters were not different among potential surrogates and target pathogens (P > 0.05). Thermal resistance was compared in phosphate-buffered saline (pH 7.4) at 55, 60, and 65°C, and D-values of potential surrogates were not different (P > 0.05) or were higher (P < 0.05) than those of the target pathogens. Acid resistance was tested in phosphate-buffered saline acidified with l-lactic acid at pH 2.5, 3.0, and 3.5, and log reductions (CFU per milliliter) were not different (P > 0.05) among potential surrogates and E. coli O157:H7 strains; however, some Salmonella serotypes were less acid resistant than were surrogates (P < 0.05). The cell surface hydrophobicity was different (P < 0.05) among surrogates and some E. coli O157:H7 strains, but the strength of attachment to beef carcasses was not different (P > 0.05) among all microorganisms. Log reductions (CFU per square centimeter) after application of hot water washes and 2% l-lactic acid sprays on beef carcasses were not different (P > 0.05) among surrogates and pathogens. The nonpathogenic E. coli strains evaluated in this study could be used as surrogates for E. coli O157:H7 and Salmonella to validate hot water and lactic acid interventions on beef carcasses.

Decontamination of Beef Subprimal Cuts Intended for Blade Tenderization or Moisture Enhancement

2007 ◽  
Vol 70 (5) ◽  
pp. 1174-1180 ◽  
Author(s):  
C. E. HELLER ◽  
J. A. SCANGA ◽  
J. N. SOFOS ◽  
K. E. BELK ◽  
W. WARREN-SERNA ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Lactic Acid ◽  
Hot Water ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Low Concentrations ◽  
Blade Tenderization ◽  
Antimicrobial Interventions

The prevalence of Escherichia coli O157:H7 on beef subprimal cuts intended for mechanical tenderization was evaluated. This evaluation was followed by the assessment of five antimicrobial interventions at minimizing the risk of transferring E. coli O157:H7 to the interior of inoculated subprimal cuts during blade tenderization (BT) or moisture enhancement (ME). Prevalence of E. coli O157:H7 on 1,014 uninoculated beef subprimals collected from six packing facilities was 0.2%. Outside round pieces inoculated with E. coli O157:H7 at 104 CFU/100 cm2 were treated with (i) no intervention, (ii) surface trimming, (iii) hot water (82°C), (iv) warm 2.5% lactic acid (55°C), (v) warm 5.0% lactic acid (55°C), or (vi) 2% activated lactoferrin followed by warm 5.0% lactic acid (55°C) and then submitted to BT or ME. Prevalence (n = 196) of internalized (BT and ME) E. coli O157:H7 was 99%. Enumeration of E. coli O157:H7 (n = 192) revealed mean surface reductions of 0.93 to 1.10 log CFU/100 cm2 for all antimicrobial interventions. E. coli O157:H7 was detected on 3 of the 76 internal BT samples and 73 of the 76 internal ME samples. Internal ME samples with no intervention had significantly higher mean E. coli O157:H7 populations than did those internal samples treated with an intervention, but there were no significant differences in E. coli O157:H7 populations among internal BT samples. Results of this study demonstrate that the incidence of E. coli O157:H7 on the surface of beef subprimal cuts is low and that interventions applied before mechanical tenderization can effectively reduce the transfer of low concentrations of E. coli O157:H7 to the interior of beef subprimal cuts.

Reducing Pathogenic Escherichia coli Surrogates on Fresh Beef Cuts by Water-Reducing Antimicrobial Interventions

2020 ◽  
Author(s):  
Kourtney A. Daniels ◽  
Katherine Modrow ◽  
Wesley N. Osburn ◽  
Thomas Matt Taylor
Keyword(s):  
Escherichia Coli ◽  
Lactic Acid ◽  
Water Use ◽  
Water Conservation ◽  
Hot Water ◽  
Water Spray ◽  
Water Losses ◽  
E Coli ◽  
Safety Interventions ◽  
Antimicrobial Interventions

Water use for antimicrobial intervention application for beef harvest has come under increased scrutiny in recent years in an effort to enhance water conservation during beef harvest and fabrication. This study was conducted to determine the efficacy of beef safety interventions for reducing surrogates of the Shiga toxin-producing Escherichia coli (STEC) on beef cuts while lowering intervention-purposed water use for a Small or Very Small beef establishment. Beef briskets, shoulder/clods, and rounds were inoculated with a gelatin-based slurry containing 6.8±0.3 log CFU/g non-pathogenic E. coli . After 30 min of attachment, inoculated cuts were treated by: conventional lactic acid spray (LA; 2.5%, 55°C), lactic acid spray delivered by an electrostatic spray handheld wand (ESS; 2.5%, 55°C), hot water spray (HW; 82°C), recycled hot water spray (RW; 82°C) wherein previously applied hot water was collected, thermally pasteurized to 82°C, or left untreated (CON). 100 mL of each treatment was sprayed onto marked surfaces of inoculated cuts, after which surviving surrogate E. coli were enumerated. LA and ESS treatments produced greater reductions (1.0-1.1 log CFU/300 cm 2 ) versus hot water interventions (0.3-0.5 log CFU/300 cm 2 ) ( p =<0.0001). Recycling of water reduced water losses by no less than 45% on RW-treated beef cuts. Low water beef safety interventions offer Small and Very Small inspected beef establishments opportunities to incrementally reduce water use during intervention application, but not necessarily without loss of pathogen reduction efficacy.

scholarly journals Isolation of Shiga toxin-producing strains of Escherichia coli from beef and swine carcasses and the characterization of their genes

2018 ◽  
Vol 9 (2) ◽  
pp. 275-780 ◽  
Author(s):  
O. М. Berhilevych ◽  
V. V. Kasianchuk ◽  
O. M. Deriabin ◽  
M. D. Kukhtyn
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Raw Material ◽  
Animal Origin ◽  
E Coli ◽  
Food Of Animal Origin ◽  
Beef Carcasses ◽  
Positive Isolate ◽  
Stx1 Gene ◽  
Beef Carcass

Escherichia coli is part of the normal microflora of the intestinal tract of humans and warm-blooded animals, but its presence in raw material and food of animal origin is considered as fecal contamination and can be very dangerous for consumers. The determination of the number of E. coli in raw material and food is important because among them can be pathogenic strains. The most dangerous strains are considered enterohemorrhagic E. coli as a causative agent of severe bloody diarrhea and hemorrhagic uremic syndrome in humans through the production of Shiga-toxin, which is the main virulence factor, responsible for disease. The aim of this study was to identify the prevalence of Shiga toxin-producing strains of E. coli (STEC) from swabs of beef and swine carcass in slaughterhouses in Ukraine and characterize their genes, which are responsible for pathogenic properties. A total of 230 samples of swabs from beef (130) and swine (100) carcasses were obtained from 5 slaughterhouses in Ukraine between 2012 and 2015. Samples of swabs from carcasses were randomly selected at the final point of the process after the final washing of the carcass from the following areas: distal hind limb, abdomen (lateral and medial) from swine carcasses, brisket, flank and flank groin areas from beef carcasses. All samples were examined by culture-dependent method, after that each positive isolate of STEC was analyzed by multiplex PCR to detect the stx1, stx2, and eae genes. Out of 230 collected samples, seven (7.2%) were contaminated with STEC. The highest prevalence of STEC was found in swabs from beef carcasses (8.1%) in comparison to swabs from swine carcasses (5.7%). The stx1 gene was the predominant gene detected in all STEC positive samples. The eae gene was found in one of the examined isolates from beef carcass. Three isolates from swabs of beef carcass carried both stx1 and stx2 genes, one isolate showed association between stx1 and eae genes, one isolate was positive for stx1 gene only. In swabs from swine carcasses (2 isolates) stx1 and stx2 genes were presented simultaneously. The results of this study suggested that fresh raw meat could be a potential vehicle for transmission of the Shiga toxin-producing strain of E. coli to humans. This is the first report of STEC prevalence in beef and swine carcasses in Ukraine and these data will be valuable for microbiological risk assessment and help the appropriate services to develop strategies to mitigate health risk.

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