Antimicrobial Activity of Gaseous Allyl Isothiocyanate

1997 ◽  
Vol 60 (8) ◽  
pp. 943-947 ◽  
Author(s):  
PASCAL J. DELAQUIS ◽  
PETER L. SHOLBERG
Keyword(s):  
Bacterial Species ◽  
Allyl Isothiocyanate ◽  
Model System ◽  
Penicillium Expansum ◽  
Escherichia Coli O157 ◽  
Fluorescent Pseudomonad ◽  
Bacterial Cells ◽  
E Coli ◽  
Simple Model System ◽  
Germination And Growth

A simple model system was constructed to evaluate the microbistatic and microbicidal properties of gaseous allyl isothiocyanate (AIT) against bacterial cells and fungal conidia deposited on agar surfaces. Salmonella typhimurium, Listeria monocytogenes Scott A, and Escherichia coli O157:H7 were inhibited when exposed to 1,000 μg AIT per liter. Pseudomonas corrugata, a Cytophaga species, and a fluorescent pseudomonad failed to grow in the presence of 500 μg AIT per liter. Germination and growth of Penicillium expansum, Aspergillus flavus, and Botrytis cinerea conidia was inhibited in the presence of 100 μg AIT per liter. Bactericidal and sporicidal activities varied with strain and increased with time of exposure, AIT concentration, and temperature. E. coli O157:H7 was the most resistant bacterial species tested.

Attachment of Escherichia coli O157:H7 and Other Bacterial Cells Grown in Two Media to Beef Adipose and Muscle Tissues

1997 ◽  
Vol 60 (2) ◽  
pp. 102-106 ◽  
Author(s):  
LAURA CABEDO ◽  
JOHN N. SOFOS ◽  
GLENN R. SCHMIDT ◽  
GARY C. SMITH
Keyword(s):  
Escherichia Coli ◽  
Adipose Tissue ◽  
Muscle Tissue ◽  
Storage Period ◽  
Escherichia Coli O157 ◽  
Bacterial Cells ◽  
Liquid Droplets ◽  
E Coli ◽  
Attachment Strength ◽  
Beef Muscle

Three strains of Escherichia coli O157:H7 were grown in tryptic soy broth (TSB) or in a sterile cattle manure extract at 35°C for 18 ± 2 h. Aliquots from both inocula containing 106 CFU/ml were used to inoculate 1-cm3 cubes of beef muscle or adipose tissue by immersion for 20 min at 21°C. After removal from the inoculum, one-half of the samples were analyzed for bacterial cell numbers and pH, and the other half were stored at 4°C for 2 or 3 h before analysis. Samples were analyzed by enumerating bacteria present in liquid droplets deposited on the tissue and bacteria loosely or strongly attached to the tissue in order to determine attachment strength. Total numbers of cells on beef muscle tissue (bacteria in liquid droplets, as well as those loosely and strongly attached) were 5.65 ± 0.14 and 5.76 ± 0.26 log CFU/cm2 for E. coli O157:H7 inocula grown in TSB and manure extract, respectively. The differences in attachment strength between inocula from the two media were not significant (P > 0.05). A 2-h storage period after exposure of muscle tissue to an E. coli O157:H7 inoculum did not influence attachment strength. Numbers of bacteria attached to adipose tissue and muscle (5.31 ± 0.08 and 5.48 ± 0.09 log CFU/cm2, respectively) were not significantly different (P > 0.05). After 3 h at 4°C, the attachment strength of E. coli O157:H7 cells on muscle or adipose tissue had not changed. Overall, the culture medium and type of beef tissue did not affect the numbers of E. coli O157:H7 cells attached, nor the strength of their attachment, to muscle or adipose tissue.

Antimicrobial Effects of Trisodium Phosphate Against Bacteria Attached to Beef Tissue

1994 ◽  
Vol 57 (11) ◽  
pp. 952-955 ◽  
Author(s):  
J. S. DICKSON ◽  
C. G. NETTLES CUTTER ◽  
G. R. SIRAGUSA
Keyword(s):  
Adipose Tissue ◽  
Bacterial Population ◽  
Model System ◽  
Trisodium Phosphate ◽  
Phosphate Solution ◽  
Escherichia Coli O157 ◽  
Lean Tissue ◽  
Bacterial Populations ◽  
Gram Negative ◽  
E Coli

Sliced beef tissue was artificially contaminated with Salmonella typhimurium, Listeria monocytogenes and Escherichia coli O157:H7. The contaminated tissue was immersed in 8, 10 and 12% solutions of trisodium phosphate at 25, 40 and 55°C with contact times of up to 3 min. The concentration of the trisodium phosphate solution was not a significant factor in reducing the populations of the bacteria on either lean or adipose tissue. Reductions in bacterial populations of 1 to 1.5 log10 cycles were obtained on lean tissue contaminated with the gram-negative pathogens, although less reduction in population was seen with L. monocytogenes. Greater reductions in bacterial populations were observed on adipose tissue, with maximum reductions of 2 to 2.5 log10 cycles and 1 to 1.5 log10 cycles for the gram-negative and the gram-positive pathogens, respectively. Typically greater reductions in bacterial populations were seen as the temperature of the trisodium phosphate solution increased. Surface beef carcass tissue was inoculated with E. coli ATCC 25922 and sanitized with 8% trisodium phosphate using a model carcass washing system. Population reductions with the carcass washer and lean tissue were comparable to those observed in the laboratory with E. coli O157:H7. However, greater reductions were observed on adipose tissue from the model system, suggesting that the physical washing procedure may have contributed to the reduction in the bacterial population.

Predicting Survival of Escherichia coli O157:H7 in Dry Fermented Sausage Using Artificial Neural Networks

2008 ◽  
Vol 71 (1) ◽  
pp. 6-12 ◽  
Author(s):  
A. PALANICHAMY ◽  
D. S. JAYAS ◽  
R. A. HOLLEY
Keyword(s):  
Escherichia Coli ◽  
Neural Networks ◽  
Artificial Neural Networks ◽  
Statistical Model ◽  
Allyl Isothiocyanate ◽  
Escherichia Coli O157 ◽  
Fermented Sausage ◽  
E Coli ◽  
Dry Fermented Sausage ◽  
Artificial Neural

The Canadian Food Inspection Agency required the meat industry to ensure Escherichia coli O157:H7 does not survive (experiences ≥ 5 log CFU/g reduction) in dry fermented sausage (salami) during processing after a series of foodborne illness outbreaks resulting from this pathogenic bacterium occurred. The industry is in need of an effective technique like predictive modeling for estimating bacterial viability, because traditional microbiological enumeration is a time-consuming and laborious method. The accuracy and speed of artificial neural networks (ANNs) for this purpose is an attractive alternative (developed from predictive microbiology), especially for on-line processing in industry. Data from a study of interactive effects of different levels of pH, water activity, and the concentrations of allyl isothiocyanate at various times during sausage manufacture in reducing numbers of E. coli O157:H7 were collected. Data were used to develop predictive models using a general regression neural network (GRNN), a form of ANN, and a statistical linear polynomial regression technique. Both models were compared for their predictive error, using various statistical indices. GRNN predictions for training and test data sets had less serious errors when compared with the statistical model predictions. GRNN models were better and slightly better for training and test sets, respectively, than was the statistical model. Also, GRNN accurately predicted the level of allyl isothiocyanate required, ensuring a 5-log reduction, when an appropriate production set was created by interpolation. Because they are simple to generate, fast, and accurate, ANN models may be of value for industrial use in dry fermented sausage manufacture to reduce the hazard associated with E. coli O157:H7 in fresh beef and permit production of consistently safe products from this raw material.

Inactivation of Escherichia coli O157:H7 and Salmonella and Native Microbiota on Fresh Strawberries by Antimicrobial Washing and Coating

2018 ◽  
Vol 81 (8) ◽  
pp. 1227-1235 ◽  
Author(s):  
MINGMING GUO ◽  
TONY Z. JIN ◽  
JOSHUA B. GURTLER ◽  
XUETONG FAN ◽  
MADHAV P. YADAV
Keyword(s):  
Escherichia Coli ◽  
Foodborne Pathogens ◽  
Allyl Isothiocyanate ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Native Microflora ◽  
Pathogen Populations ◽  
Antimicrobial Treatments ◽  
Antimicrobial Effectiveness

ABSTRACT Antimicrobial washing (AW), antimicrobial coating (AC), and a combination of washing followed by coating (AW+AC) were evaluated for their ability to inactivate artificially inoculated foodborne pathogens and native microbiota on strawberries stored at 4°C. Strawberries were inoculated with a six-strain composite of Escherichia coli O157:H7 and Salmonella; treated by AW, AC, or AW+AC; and stored at 4°C for 3 weeks. The washing solution contained 90 ppm of peracetic acid, and the coating solution consisted of chitosan (1%, w/v), allyl isothiocyanate (1%, v/v), and corn-bio fiber gum (5%, w/v). The effectiveness of the antimicrobial treatments against E. coli O157:H7 and Salmonella pathogens and native microflora on strawberries and their impact on fruit quality (appearance, weight loss, color, and firmness) were determined. By the end of storage, pathogen populations on strawberries were 2.5 (AW+AC), 2.9 (AC), 3.8 (AW), and 4.2 log CFU for the positive (untreated) control. AW+AC treatments also inactivated the greatest population of native microflora, followed by the AC treatment alone. AW+AC treatments showed additional antimicrobial effectiveness against these two pathogens and native microflora. Both AW+AC and AC treatments preserved the color, texture, and appearance of strawberries throughout storage. The coating treatments (AW+AC and AC alone) further reduced the loss of moisture throughout storage. The AW treatment was the least effective in reducing populations of pathogens and native microflora and in maintaining the quality of strawberries throughout storage. This study demonstrates a method to improve the microbiological safety, shelf life, and quality of strawberries.

Effects of Plant-Derived Extracts, Other Antimicrobials, and Their Combinations against Escherichia coli O157:H7 in Beef Systems

2015 ◽  
Vol 78 (6) ◽  
pp. 1090-1097 ◽  
Author(s):  
KYUNG YUK KO ◽  
IFIGENIA GEORNARAS ◽  
HYUN-DONG PAIK ◽  
KEE-TAE KIM ◽  
JOHN N. SOFOS
Keyword(s):  
Escherichia Coli ◽  
Lactic Acid ◽  
Untreated Control ◽  
Sodium Tripolyphosphate ◽  
Model System ◽  
Surface Contamination ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Blade Tenderization ◽  
Sodium Diacetate

The antimicrobial effects of thyme oil (TO), grapefruit seed extract (GSE), and basil essential oil, alone or in combination with cetylpyridinium chloride (CPC), sodium diacetate, or lactic acid, were evaluated against Escherichia coli O157:H7 in a moisture-enhanced beef model system. The model system was composed of a nonsterile beef homogenate to which NaCl (0.5%) and sodium tripolyphosphate (0.25%) were added, together with the tested antimicrobial ingredients. Beef homogenate treatments were inoculated (ca. 3 log CFU/ml) with rifampin-resistant E. coli O157:H7 (eight-strain mixture) and incubated at 15°C (48 h). The most effective individual treatments were TO (0.25 or 0.5%) and GSE (0.5 or 1.0%), which immediately reduced (P < 0.05) pathogen levels by ≥3.4 log CFU/ml. Additionally, CPC (0.04%) reduced initial E. coli O157:H7 counts by 2.7 log CFU/ml. Most combinations of the tested plant-derived extracts with CPC (0.02 or 0.04%) and sodium diacetate (0.25%) had an additive effect with respect to antibacterial activity. In a second study, antimicrobial interventions were evaluated for their efficacy in reducing surface contamination of E. coli O157:H7 on beef cuts and to determine the effect of these surface treatments on subsequent internalization of the pathogen during blade tenderization. Beef cuts (10 by 8 by 3.5 cm) were inoculated (ca. 4 log CFU/g) on one side with the rifampin-resistant E. coli O157:H7 strain mixture and were then spray treated (20 lb/in2, 10 s) with water, GSE (5 and 10%), lactic acid (5%), or CPC (5%). Untreated (control) and spray-treated surfaces were then subjected to double-pass blade tenderization. Surface contamination (4.4 log CFU/g) of E. coli O157:H7 was reduced (P < 0.05) to 3.4 (5% CPC) to 4.1 (water or 5% GSE) log CFU/g following spray treatment. The highest and lowest transfer rates of pathogen cells from the surface to deeper tissues of blade-tenderized sections were obtained in the untreated control and CPC-treated samples, respectively.

Effectiveness and Functional Mechanism of a Multicomponent Sanitizer against Biofilms Formed by Escherichia coli O157:H7 and Five Salmonella Serotypes Prevalent in the Meat Industry

2020 ◽  
Vol 83 (4) ◽  
pp. 568-575
Author(s):  
RONG WANG ◽  
YOU ZHOU ◽  
NORASAK KALCHAYANAND ◽  
DAYNA M. HARHAY ◽  
TOMMY L. WHEELER
Keyword(s):  
Escherichia Coli ◽  
Salmonella Enterica ◽  
Three Dimensional ◽  
Short Exposure ◽  
Escherichia Coli O157 ◽  
Bacterial Cells ◽  
Meat Processing ◽  
E Coli ◽  
Biofilm Removal ◽  
Biofilm Structure

ABSTRACT Biofilm formation by Escherichia coli O157:H7 and Salmonella enterica at meat processing plants poses a potential risk of meat product contamination. Many common sanitizers are unable to completely eradicate biofilms formed by these foodborne pathogens because of the three-dimensional biofilm structure and the presence of bacterial extracellular polymeric substances (EPSs). A novel multifaceted approach combining multiple chemical reagents with various functional mechanisms was used to enhance the effectiveness of biofilm control. We tested a multicomponent sanitizer consisting of a quaternary ammonium compound (QAC), hydrogen peroxide, and the accelerator diacetin for its effectiveness in inactivating and removing Escherichia coli O157:H7 and Salmonella enterica biofilms under meat processing conditions. E. coli O157:H7 and Salmonella biofilms on common contact surfaces were treated with 10, 20, or 100% concentrations of the multicomponent sanitizer solution for 10 min, 1 h, or 6 h, and log reductions in biofilm mass were measured. Scanning electron microscopy (SEM) was used to directly observe the effect of sanitizer treatment on biofilm removal and bacterial morphology. After treatment with the multicomponent sanitizer, viable E. coli O157:H7 and Salmonella biofilm cells were below the limit of detection, and the prevalence of both pathogens was low. After treatment with a QAC-based control sanitizer, surviving bacterial cells were countable, and pathogen prevalence was higher. SEM analysis of water-treated control samples revealed the three-dimensional biofilm structure with a strong EPS matrix connecting bacteria and the contact surface. Treatment with 20% multicomponent sanitizer for 10 min significantly reduced biofilm mass and weakened the EPS connection. The majority of the bacterial cells had altered morphology and compromised membrane integrity. Treatment with 100% multicomponent sanitizer for 10 min dissolved the EPS matrix, and no intact biofilm structure was observed; instead, scattered clusters of bacterial aggregates were detected, indicating the loss of cell viability and biofilm removal. These results indicate that the multicomponent sanitizer is effective, even after short exposure with dilute concentrations, against E. coli O157:H7 and S. enterica biofilms. HIGHLIGHTS

Primers with 5′ Flaps Improve the Efficiency and Sensitivity of Multiplex PCR Assays for the Detection of Salmonella and Escherichia coli O157:H7

2013 ◽  
Vol 76 (4) ◽  
pp. 668-673 ◽  
Author(s):  
CHRIS TIMMONS ◽  
SHEFALI DOBHAL ◽  
JACQUELINE FLETCHER ◽  
LI MARIA MA
Keyword(s):  
Escherichia Coli ◽  
Multiplex Pcr ◽  
Fold Increase ◽  
Detection Sensitivity ◽  
Escherichia Coli O157 ◽  
Bacterial Cells ◽  
Robust Detection ◽  
E Coli ◽  
Pcr Multiplex ◽  
Pcr Assays

Foodborne illnesses caused by Salmonella enterica and Escherichia coli O157:H7 are worldwide health concerns. Rapid, sensitive, and robust detection of these pathogens in foods and in clinical and environmental samples is essential for routine food quality testing, effective surveillance, and outbreak investigations. The aim of this study was to evaluate the effect on PCR sensitivity of adding a short, AT-rich overhanging nucleotide sequence (flap) to the 5′ end of PCR primers specific for the detection of Salmonella and E. coli O157:H7. Primers targeting the invA gene of Salmonella and the rfbE gene of E. coli O157:H7 were synthesized with or without a 12-bp, AT-rich 5′ flap (5′-AATAAATCATAA-3′). Singleplex PCR, multiplex PCR, and real-time PCR sensitivity assays were conducted using purified bacterial genomic DNA and crude cell lysates of bacterial cells. The effect of background flora on detection was evaluated by spiking tomato and jalapeno pepper surface washes with E. coli O157:H7 and Salmonella Saintpaul. When targeting individual pathogens, end-point PCR assays using flap-amended primers were more efficient than nonamended primers, with 20.4 and 23.5% increases in amplicon yield for Salmonella and E. coli O157:H7, respectively. In multiplex PCR assays, a 10- to 100-fold increase in detection sensitivity was observed when the primer flap sequence was incorporated. This improvement in both singleplex and multiplex PCR efficiency and sensitivity can lead to improved Salmonella and E. coli O157:H7 detection.

Effects of Oxidative Compounds on Thermotolerance in Escherichia coli O157:H7 Strains EO139 and 380-94

2005 ◽  
Vol 68 (11) ◽  
pp. 2443-2446 ◽  
Author(s):  
ISABEL C. BLACKMAN ◽  
YOUNG W. PARK ◽  
MARK A. HARRISON
Keyword(s):  
Oxidative Stress ◽  
Escherichia Coli ◽  
Ascorbic Acid ◽  
Lethal Effect ◽  
Iron Chloride ◽  
Plate Count ◽  
Escherichia Coli O157 ◽  
Bacterial Cells ◽  
E Coli ◽  
Chloride Hexahydrate

An oxidative complex composed of ferric iron chloride hexahydrate, ADP, and ascorbic acid can generate hydrogen peroxide and hydroxyl radicals in fibroblasts. These compounds are naturally found in meat and meat-based products and may elicit oxidative stress on Escherichia coli O157:H7, thus conferring thermotolerance to the bacterium due to the phenomenon of the global stress response. The effect of the levels of the oxidative complex on the thermotolerance of E. coli O157:H7 was investigated. Cultures of E. coli O157:H7 strains EO139 and 380-94 were mixed in three different concentrations (10:10: 40, 15:15:60, and 20:20:80 μM) of the oxidative complex (iron III chloride, ADP, and ascorbic acid, respectively). The samples were inserted into capillary tubes and heated in a circulating water bath at 59 and 60°C for EO139 and 380-94, respectively. Tubes were removed at intervals of 5 min for up to 1 h and contents spirally plated on plate count agar that was incubated for 48 h at 37°C. The thermotolerance of both E. coli O157:H7 strains EO139 and 380-94 was influenced by the concentrations of the oxidative complex. The ratio of 10:10:40 μM enhanced thermotolerance of EO139 and 390-94 at 59 and 60°C, respectively. However, exposure to the ratios of 15:15:60 and 20:20:80 μM rendered the pathogen more sensitive to the lethal effect and did not enhance the thermotolerance of the cells. The significance of this study is twofold. This experiment proves that oxidative stress can enhance thermotolerance of bacterial cells induced by an oxidative complex if only in a specific ratio and concentration. It is possible to speculate that if the chemical compounds are present in this ratio in meats, they may enhance the thermal resistance of E. coli O157:H7 and make the bacteria more difficult to eliminate, thus increasing the risk of foodborne illness in consumers.

scholarly journals Modifying TIMER, a slow-folding DsRed derivative, for optimal use in quickly-dividing bacteria

2021 ◽  
Author(s):  
Pavan Patel ◽  
Brendan J. O’Hara ◽  
Emily Aunins ◽  
Kimberly M. Davis
Keyword(s):  
Nitric Oxide ◽  
Cell Division ◽  
Stationary Phase ◽  
Yersinia Pseudotuberculosis ◽  
Fluorescent Protein ◽  
Bacterial Species ◽  
Bacterial Cells ◽  
E Coli ◽  
Slow Growing ◽  
Host Tissues

AbstractIt is now well appreciated that members of pathogenic bacterial populations exhibit heterogeneity in growth rates and metabolic activity, and it is known this can impact the ability to eliminate all members of the bacterial population during antibiotic treatment. It remains unclear which pathways promote slowed bacterial growth within host tissues, primarily because it has been difficult to identify and isolate slow growing bacteria from host tissues for downstream analyses. To overcome this limitation, we have developed a novel variant of TIMER, a slow-folding fluorescent protein, to identify subsets of slowly dividing bacteria within host tissues. The original TIMER folds too slowly for fluorescence accumulation in quickly replicating bacterial species (Escherichia coli, Yersinia pseudotuberculosis), however this TIMER42 variant accumulates signal in late stationary phase cultures of E. coli and Y. pseudotuberculosis. We show TIMER42 signal also accumulates during exposure to sources of nitric oxide (NO), suggesting TIMER42 signal detects growth-arrested bacterial cells. In a mouse model of Y. pseudotuberculosis deep tissue infection, TIMER42 signal is clearly detected, and primarily accumulates in bacteria expressing markers of stationary phase growth. There was not significant overlap between TIMER42 signal and NO-exposed subpopulations of bacteria within host tissues, suggesting NO stress was transient, allowing bacteria to recover from this stress and resume replication. This novel TIMER42 variant represents a new faster folding TIMER that will enable additional studies of slow-growing subpopulations of bacteria, specifically within bacterial species that quickly divide.Author SummaryWe have generated a variant of TIMER that can be used to mark slow-growing subsets of Yersinia pseudotuberculosis, which has a relatively short division time, similar to E. coli. We used a combination of site-directed and random mutagenesis to generate the TIMER42 variant, which has red fluorescent signal accumulation in post-exponential or stationary phase cells. We found that nitric oxide (NO) stress is sufficient to promote TIMER42 signal accumulation in culture, however within host tissues, TIMER42 signal correlates with a stationary phase reporter (dps). These results suggest NO may cause an immediate arrest in bacterial cell division, but during growth in host tissues exposure to NO is transient, allowing bacteria to recover from this stress and resume cell division. Thus instead of indicating a response to host stressors, TIMER42 signal accumulation within host tissues appears to identify slow-growing cells that are experiencing nutrient limitation.

scholarly journals Bioremediation of Diazinon, Pirimicarb and Atrazine Pesticides Using Bacterial Species

2021 ◽  
pp. 14-20
Keyword(s):  
Growth Rate ◽  
Bacterial Growth ◽  
Bacterial Species ◽  
Serial Dilution ◽  
Bacterial Cells ◽  
E Coli ◽  
Highly Efficient

Bacterial species such as E.coli, S. aureus and Sa. bongori were isolated from soil by using serial dilution. Bioremediation results showed the S. aureus was highly efficient on Diazinon removal by 62%, 63.2% and 68.6%, Pirimicarb removal was 44%, 52.4% and 53.8%, and Atrazine removal was 61%, 65.6% and 70.6%. and the efficiency of E.coli removal on Diazinon was 59%, 60.8% and 63.8%; on Pirimicarb was 44%, 52.4% and 53.8%; and for Atrazine 57%, 60.8% and 64.4%. Sa. bongori efficiency on Diazinon was 49%, 51.2% and 55.8%; on Pirimicarb removal was 61%, 63.2% and 68.4%; Also, in Atrazine removal 48%, 50.4% and 57.2%. When comparing the growth rate of bacterial cells. The bacterial cells before treatment with S. aureus was 22.01×10^4, Results after treatment showed Diazinon of 35.58×10^4. The Pirimicarb 32.41×10^4 and Atrazine was 38.45 ×10^4. Either E. coli Its bacterial growth was before treatment 17.09×10^4 To show the results of growth on diazinon 30.43×10^4, Pirimicarb 27.71×10^4 and Atrazine 24.34 ×10^4. While the growth was in Sa. bongori Before treatment 10.09×10^4 While recorded a growth rate on Diazinon 18.82×10^4, Pirimicarb 19.98×10^4 and Atrazine 17.08 ×10^4.These bacterial species efficiencies on bioremediation of these three pesticides proved to be promising It can be used safely in the process of removing pesticides, yet more research on safety, mechanisms and kinetics needs to be further investigated.

Sign in / Sign up

Export Citation Format

Share Document