scholarly journals Survival of Acid Resistant Shiga Toxin-Producing Escherichia coli to Organic and Inorganic Acids

2019 ◽  
Vol 3 (2) ◽  
Author(s):  
K. M. Villatoro ◽  
L. Yang ◽  
X. Yang
Keyword(s):  
Escherichia Coli ◽  
Lactic Acid ◽  
Hydrochloric Acid ◽  
Organic Acid ◽  
Shiga Toxin ◽  
Extended Period ◽  
Human Stomach ◽  
Meat Production ◽  
Inorganic Acid ◽  
Production Chain

ObjectivesThe shiga toxin-producing Escherichia coli (STEC) has been involved in a series of outbreaks around the world. Organic acids, such as lactic acid, have been used in meat plants to control STEC. However, STEC has shown its capacity to survive in low acid environments, which may compromise the effectiveness of organic acid interventions. Similarly, STEC may also survive in human stomach fluid (pH 1.5– 3.5), which can potentially result in clinical infections. Thus, the objective was to compare the ability of acid-resistant (AR) STEC to survive in inorganic and organic acid at different pH levels.Materials and MethodsFor this study, five AR STEC strains were used to make an inoculum for the study. The AR STEC inoculum was challenged in acidified TSB with lactic acid (2% at pH 3.2; 5% at pH 2.8) and TSB with hydrochloric acid (HCl; to simulate human stomach acid) at pH 1.6, 2.8, 3.2 and 3.5 for 2, 4, 6, and 8 h at 37°C. After the acid challenge, the survival bacteria counts were plated on TSA plates and incubated for 48 h at 37°C. The complete experiment was repeated five times. The data was analyzed using the generalized linear model of the SAS 9.4.ResultsThe AR STEC showed a distinct ability to survive in organic and inorganic acid, even with the same pH. Exposure of AR STEC to HCl with pH 3.2 and 3.5 for 8 h resulted in the highest (P < 0.01) survival counts across all the treatments. When AR STEC was challenged with HCl at pH 1.6, no survival cells were recovered on TSA plates after 4 h. No additional reduction of AR STEC was observed when exposure time to HCl at pH 2.8 and 3.2 was increased. However, no growth (P < 0.01) of AR STEC was observed after exposure to lactic acid at the same pH by time.ConclusionLactic acid (2% and 5%) effectively controlled the growth of AR STEC in pure culture. However, if AR STEC can survive through the meat production chain, they may survive in the human stomach for an extended period when the pH is higher than 1.6. The results of the study emphasize that it is necessary to eliminate AR STEC before they enter the human body, as they are more resistant in inorganic acid, such as the HCl found in human stomach fluid.Table 8Least squares means (LSmeans; standard error) of the survival counts for acid-resistant Escherichia coli exposed to hydrochloric acid (HCl) and lactic acid (LA) at different pH through time. a-g Least squares means with a different superscript letter are significantly different (P < 0.05).

Mitigating the Antimicrobial Activities of Selected Organic Acids and Commercial Sanitizers with Various Neutralizing Agents

2011 ◽  
Vol 74 (5) ◽  
pp. 820-825 ◽  
Author(s):  
YOEN JU PARK ◽  
JINRU CHEN
Keyword(s):  
Escherichia Coli ◽  
Acetic Acid ◽  
Lactic Acid ◽  
Organic Acids ◽  
Shiga Toxin ◽  
Room Temperature ◽  
Sodium Thiosulfate ◽  
Antimicrobial Activities ◽  
Phosphate Buffered Saline ◽  
Lactic Acids

This study was conducted to evaluate the abilities of five neutralizing agents, Dey-Engley (DE) neutralizing broth (single or double strength), morpholinepropanesulfonic acid (MOPS) buffer, phosphate-buffered saline (PBS), and sodium thiosulfate buffer, in mitigating the activities of acetic or lactic acid (2%) and an alkaline or acidic sanitizer (a manufacturer-recommended concentration) againt the cells of Shiga toxin–producing Escherichia coli (STEC; n = 9). To evaluate the possible toxicity of the neutralizing agents to the STEC cells, each STEC strain was exposed to each of the neutralizing agents at room temperature for 10 min. Neutralizing efficacy was evaluated by placing each STEC strain in a mixture of sanitizer and neutralizer under the same conditions. The neutralizing agents had no detectable toxic effect on the STEC strains. PBS was least effective for neutralizing the activity of selected organic acids and sanitizers. Single-strength DE and sodium thiosulfate neutralized the activity of both acetic and lactic acids. MOPS buffer neutralized the activity of acetic acid and lactic acid against six and five STEC strains, respectively. All neutralizing agents, except double-strength DE broth, had a limited neutralizing effect on the activity of the commercial sanitizers used in the study. The double-strength DE broth effectively neutralized the activity of the two commercial sanitizers with no detectable toxic effects on STEC cells.

scholarly journals Effect of Exposure Time and Organic Matter on Efficacy of Antimicrobial Compounds against Shiga Toxin–Producing Escherichia coli and Salmonella

2016 ◽  
Vol 79 (4) ◽  
pp. 561-568 ◽  
Author(s):  
NORASAK KALCHAYANAND ◽  
MOHAMMAD KOOHMARAIE ◽  
TOMMY L. WHEELER
Keyword(s):  
Escherichia Coli ◽  
Organic Matter ◽  
Lactic Acid ◽  
Exposure Time ◽  
Shiga Toxin ◽  
Peracetic Acid ◽  
Antimicrobial Compounds ◽  
Number Of Factors ◽  
Hypobromous Acid ◽  
Processing Plants

ABSTRACT 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. The objective of this study was to evaluate effectiveness of time of exposure of various antimicrobial compounds against nine strains of Shiga toxin–producing Escherichia coli (STEC) and four strains of Salmonella in aqueous antimicrobial solutions with and without organic matter. Non-O157 STEC, STEC O157:H7, and Salmonella were exposed to the following aqueous antimicrobial solutions with or without beef purge for 15, 30, 60, 120, 300, 600, and 1,800 s: (i) 2.5% lactic acid, (ii) 4.0% lactic acid, (iii) 2.5% Beefxide, (iv) 1% Aftec 3000, (v) 200 ppm of peracetic acid, (vi) 300 ppm of hypobromous acid, and (vii) water as a control. In general, increasing exposure time to antimicrobial compounds significantly (P ≤ 0.05) increased the effectiveness against pathogens tested. In aqueous antimicrobial solutions without organic matter, both peracetic acid and hypobromous acid were the most effective in inactivating populations of STEC and Salmonella, providing at least 5.0-log reductions with exposure for 15 s. However, in antimicrobials containing organic matter, 4.0% lactic acid was the most effective compound in reducing levels of STEC and Salmonella, providing 2- to 3-log reductions with exposure for 15 s. The results of this study indicated that organic matter and exposure time influenced the efficacy of antimicrobial compounds against pathogens, especially with oxidizer compounds. These factors should be considered when choosing an antimicrobial compound for an intervention.

Escherichia coli O157 Diversity with Respect to Survival during Drying on Concrete

2003 ◽  
Vol 66 (5) ◽  
pp. 780-786 ◽  
Author(s):  
S. M. AVERY ◽  
S. BUNCIC
Keyword(s):  
Escherichia Coli ◽  
Survival Rate ◽  
Phage Type ◽  
Survival Rates ◽  
Pfge Type ◽  
Meat Production ◽  
Escherichia Coli O157 ◽  
Production Chain ◽  
E Coli ◽  
Wide Range

Shiga toxin (Stx)–producing Escherichia coli O157 isolates (n = 123) were divided into groups according to origin, genotype (pulsed-field gel electrophoresis [PFGE] type, or ribotype), type of Stx produced, or phage type (PT). The survival rate ([number of CFU after 24 h of drying/number of CFU before drying] × 100) for each isolate was determined in triplicate after drying on concrete for 24.0 h. The overall mean survival rate among the 123 E. coli O157 isolates studied was 22.9%, but there was a wide range of responses to drying on concrete, with a minimum of 1.2% and a maximum of 61.9% of the initial inocula being recovered after drying. Among the groups, those isolates that originated from cases of human disease were, on average, significantly more sensitive (P &lt; 0.001) to drying (with a mean survival rate of 15.3%) than isolates from the other three sources (with mean survival rates of 27.7, 26.0, and 22.9% for meats, bovine or ovine feces, and bovine hides, respectively). When the isolates were grouped by genotype, three of the PFGE types were, on average, significantly more resistant to drying than two other PFGE types were, and similarly, significant differences in average resistance to drying between groups of E. coli O157 with different ribotypes were seen. There were no differences between the abilities of isolates producing different Stxs (Stx 1 or Stx 1 and Stx 2) to survive drying. E. coli O157 isolates of PT4, PT21/28, and PT32 survived drying on concrete better than groups of other PTs did. Since the E. coli O157 isolates had various abilities to survive drying on concrete, drying could contribute to a kind of E. coli O157 natural selection along the meat chain. This possibility may have significant meat safety implications if a range of E. coli O157 isolates are simultaneously exposed to drying at any point along the meat production chain. Those E. coli O157 isolates that are more able to survive drying could be more likely to pass farther along the meat chain and ultimately reach consumers.

scholarly journals Broiler Farms and Carcasses Are an Important Reservoir of Multi-Drug Resistant Escherichia coli in Ecuador

2020 ◽  
Vol 7 ◽  
Author(s):  
David Ortega-Paredes ◽  
Sofía de Janon ◽  
Fernando Villavicencio ◽  
Katherine Jaramillo Ruales ◽  
Kenny De La Torre ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Resistance ◽  
Animal Health ◽  
Poultry Meat ◽  
Meat Production ◽  
Drug Resistant ◽  
Food Component ◽  
Production Chain ◽  
Animal Food ◽  
E Coli

Antimicrobial resistance (AMR) is a major health threat for public and animal health in the twenty-first century. In Ecuador, antibiotics have been used by the poultry industry for decades resulting in the presence of multi-drug resistant (MDR) bacteria in the poultry meat production chain, with the consequent risk for public health. This study evaluated the prevalence of ESBL/AmpC and mcr genes in third-generation cephalosporin-resistant Escherichia coli (3GC-R E. coli) isolated from broiler farms (animal component), broiler carcasses (food component), and human enteritis (human component) in Quito-Ecuador. Samples were collected weekly from November 2017 to November 2018. For the animal, food, and human components, 133, 335, and 302 samples were analyzed, respectively. Profiles of antimicrobial resistance were analyzed by an automated microdilution system. Resistance genes were studied by PCR and Sanger sequencing. From all samples, 122 (91.7%), 258 (77%), and 146 (48.3%) samples were positive for 3GC-R E. coli in the animal, food, and human components, respectively. Most of the isolates (472/526, 89.7%) presented MDR phenotypes. The ESBL blaCTX-M-55, blaCTX-M-3, blaCTX-M-15, blaCTX-M-65, blaCTX-M-27, and blaCTX-M-14 were the most prevalent ESBL genes while blaCMY-2 was the only AmpC detected gene. The mcr-1 gene was found in 20 (16.4%), 26 (10.1%), and 3 (2.1%) of isolates from animal, food, and human components, respectively. The implication of poultry products in the prevalence of ESBL/AmpC and mcr genes in 3GC-R must be considered in the surveillance of antimicrobial resistance.

scholarly journals From Farm to Table: Follow-Up of Shiga Toxin-Producing Escherichia coli Throughout the Pork Production Chain in Argentina

2016 ◽  
Vol 7 ◽  
Author(s):  
Rocío Colello ◽  
María E. Cáceres ◽  
María J. Ruiz ◽  
Marcelo Sanz ◽  
Analía I. Etcheverría ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Production Chain ◽  
Pork Production

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.

Sign in / Sign up

Export Citation Format

Share Document