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.

Population Reductions of Gram-Negative Pathogens Following Treatments with Nisin and Chelators under Various Conditions

1995 ◽  
Vol 58 (9) ◽  
pp. 977-983 ◽  
Author(s):  
CATHERINE N. CUTTER ◽  
GREGORY R. SIRAGUSA
Keyword(s):  
Divalent Cations ◽  
Escherichia Coli O157 ◽  
Gram Negative Bacteria ◽  
Bacterial Populations ◽  
Gram Negative ◽  
E Coli ◽  
Transmission Electron ◽  
Colony Forming Units ◽  
Citrate Phosphate

When used in combination with chelating agents (EDTA, EGTA, citrate, phosphate), the bacteriocin nisin is effective for reducing populations of gram-negative bacteria in vitro. This study examined parameters (buffers, temperature presence of divalent cations) that affect nisin inhibition of Escherichia coli O157:H7 and Salmonella typhimurium. Approximately 7 log10 colony-forming units (CFU) per ml of E. coli and S. typhimurium were treated in PBS or MOPS buffers containing 50 μg/ml of purified nisin, alone or in combination with 500 mM lactate, 100 mM citrate, 50 mM EDTA, and 1% (wt/vol) sodium hexametaphosphate (pH 7.0) at 37°C for 60 min or 5°C for 30 min. Surviving bacterial populations were compared to untreated controls (buffers without nisin). Data indicated that treatments with nisin in buffers resulted in reductions of 4.30 and 2.30 log10 CFU/ml of E. coli and S. typhimurium, respectively, as compared to untreated controls. Population reductions ranging from 2.29 to 5.49 log10 CFU/ml were observed when cells were treated with nisin and chelator combinations at either 37°C for 60 min or 5°C for 30 min. The addition of magnesium and calcium to buffers with nisin decreased inhibition. Data obtained from spectrophotometric experiments indicated that treatments were causing the release of cellular constituents. However, transmission electron microscopy (TEM) analyses were inconclusive, since cellular membranes did not appear to be disrupted.

A Comparison of Different Chemical Sanitizers for Inactivating Escherichia coli O157:H7 and Listeria monocytogenes in Solution and on Apples, Lettuce, Strawberries, and Cantaloupe

2004 ◽  
Vol 67 (4) ◽  
pp. 721-731 ◽  
Author(s):  
STEPHANIE L. RODGERS ◽  
JERRY N. CASH ◽  
MOHAMMAD SIDDIQ ◽  
ELLIOT T. RYSER
Keyword(s):  
Escherichia Coli ◽  
Listeria Monocytogenes ◽  
Chlorine Dioxide ◽  
Model System ◽  
Trisodium Phosphate ◽  
Escherichia Coli O157 ◽  
Peroxyacetic Acid ◽  
E Coli ◽  
Log Reduction ◽  
Yeasts And Molds

Ozone (3 ppm), chlorine dioxide (3 and 5 ppm), chlorinated trisodium phosphate (100- and 200-ppm chlorine), and peroxyacetic acid (80 ppm) were assessed for reduction of Escherichia coli O157:H7 and Listeria monocytogenes in an aqueous model system and on inoculated produce. Initially, sanitizer solutions were inoculated to contain approximately 106 CFU/ml of either pathogen, after which aliquots were removed at 15-s intervals over a period of 5 min and appropriately plated to determine log reduction times. Produce was dip inoculated to contain ~106 E. coli O157:H7 or L. monocytogenes CFU/g, held overnight, submerged in each sanitizer solution for up to 5 min, and then examined for survivors. In the model system study, both pathogens decreased >5 log following 2 to 5 min of exposure, with ozone being most effective (15 s), followed by chlorine dioxide (19 to 21 s), chlorinated trisodium phosphate (25 to 27 s), and peroxyacetic acid (70 to 75 s). On produce, ozone and chlorine dioxide (5 ppm) were most effective, reducing populations ~5.6 log, with chlorine dioxide (3 ppm) and chlorinated trisodium phosphate (200 ppm chlorine) resulting in maximum reductions of ~4.9 log. Peroxyacetic acid was the least effective sanitizer (~4.4-log reductions). After treatment, produce samples were stored at 4°C for 9 days and quantitatively examined for E. coli O157:H7, L. monocytogenes, mesophilic aerobic bacteria, yeasts, and molds. Populations of both pathogens remained relatively unchanged, whereas numbers of mesophilic bacteria increased 2 to 3 log during storage. Final mold and yeast populations were significantly higher than initial counts for chlorine dioxide- and ozone-treated produce. Using the nonextended triangle test, whole apples exposed to chlorinated trisodium phosphate (200 ppm chlorine) and shredded lettuce exposed to peroxyacetic acid were statistically different from the other treated samples.

Efficacy of Organic Acids Against Escherichia coli O157:H7 Attached to Beef Carcass Tissue Using a Pilot Scale Model Carcass Washer1

1994 ◽  
Vol 57 (2) ◽  
pp. 97-103 ◽  
Author(s):  
CATHERINE NETTLES CUTTER ◽  
GREGORY R. SIRAGUSA
Keyword(s):  
Escherichia Coli ◽  
Organic Acids ◽  
Pilot Scale ◽  
Scale Model ◽  
Tissue Type ◽  
Escherichia Coli O157 ◽  
Lean Tissue ◽  
Bacterial Populations ◽  
E Coli ◽  
Beef Carcass

The efficacy of organic acids for controlling Escherichia coli O157:H7 attached to beef carcass tissue was determined using a pilot scale model carcass washer. Lean or adipose surface tissues from beef carcasses were inoculated with three strains of Escherichia coli O157:H7 or Pseudomonas fluorescens. After spraying either water, 1, 3, or 5% acetic, lactic, or citric acids at 24°C, tissues were incubated for 24 h at 4°C and bacterial populations enumerated. Statistical analyses of the data indicated that acid type was not a significant treatment factor (p ≥ = 0.05); however, concentration, tissue type, and bacterial strain were significant (p ≤ = 0.0001) factors that influenced the reduction of bacterial populations on lean or adipose tissue. Of the concentrations tested on lean tissue, spray treatments with 5% were the most effective for reducing populations of E. coli O157:H7 or P. fluorescens. Differences in the resistances of the E. coli O157:H7 strains to acid washing also were observed. The magnitude of bacterial population reductions was consistently greater on adipose versus lean tissue for all bacterial strains. Surface pH data indicated that reductions of bacterial populations may have been due to the effects of acidic pH. This study demonstrates that, while organic acids did reduce populations of E. coli O157:H7 on red meat, treatments did not completely inactivate the pathogen.

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.

Ascorbic Acid Enhances Destruction of Escherichia coli O157:H7 during Home-Type Drying of Apple Slices

2001 ◽  
Vol 64 (8) ◽  
pp. 1244-1248 ◽  
Author(s):  
JENNIFER A. BURNHAM ◽  
PATRICIA A. KENDALL ◽  
JOHN N. SOFOS
Keyword(s):  
Escherichia Coli ◽  
Ascorbic Acid ◽  
Acid Solution ◽  
Escherichia Coli O157 ◽  
Bacterial Populations ◽  
Ascorbic Acid Solution ◽  
Initial Inoculum ◽  
E Coli ◽  
Apple Slices ◽  
Agar Media

Destruction of Escherichia coli O157:H7 was evaluated on inoculated apple slices dehydrated at two temperatures with and without application of predrying treatments. Half-ring slices (0.6 cm thick) of peeled and cored Gala apples were inoculated by immersion for 30 min in a four-strain composite inoculum of E. coli O157:H7. The inoculated slices (8.7 to 9.4 log CFU/g) either received no predrying treatment (control), were soaked for 15 min in a 3.4% ascorbic acid solution, or were steam blanched for 3 min at 88°C immediately prior to drying at 57.2 or 62.8°C for up to 6 h. Samples were plated on tryptic soy (TSA) and sorbitol MacConkey (SMAC) agar media for direct enumeration of surviving bacterial populations. Steam blanching changed initial inoculation levels by +0.3 to −0.7 log CFU/g, while immersion in the ascorbic acid solution reduced the inoculation levels by 1.4 to 1.6 log CFU/g. Dehydration of control samples for 6 h reduced mean bacterial populations by 2.9 log CFU/g (TSA or SMAC) at 57.2°C and by 3.3 (SMAC) and 3.5 (TSA) log CFU/g at 62.8°C. Mean decreases from initial inoculum levels for steam-blanched slices after 6 h of drying were 2.1 (SMAC) and 2.0 (TSA) log CFU/g at 57.2°C, and 3.6 (TSA or SMAC) log CFU/g at 62.8°C. In contrast, initial bacterial populations on ascorbic acid–pretreated apple slices declined by 5.0 (SMAC) and 5.1 (TSA) log CFU/g after 3 h of dehydration at 57.2°C, and by 7.3 (SMAC) and 6.9 (TSA) log CFU/g after 3 h at 62.8°C. Reductions on slices treated with ascorbic acid were in the range of 8.0 to 8.3 log CFU/g after 6 h of drying, irrespective of drying temperature or agar medium used. The results of immersing apple slices in a 3.4% ascorbic acid solution for 15 min prior to drying indicate that a predrying treatment enhances the destruction of E. coli O157:H7 on home-dried apple products.

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.

Synergistic Effect of High Temperature and High pH on the Destruction of Salmonella enteritidis and Escherichia co1i O157:H7

1996 ◽  
Vol 59 (10) ◽  
pp. 1023-1030 ◽  
Author(s):  
YEOW-LIM TEO ◽  
TIMOTHY J. RAYNOR ◽  
KAMESWAR R. ELLAJOSYULA ◽  
STEPHEN J. KNABEL
Keyword(s):  
Escherichia Coli ◽  
High Temperature ◽  
Synergistic Effect ◽  
Foodborne Pathogens ◽  
Salmonella Enteritidis ◽  
Synergistic Interaction ◽  
Escherichia Coli O157 ◽  
Gram Negative ◽  
High Ph ◽  
E Coli

This study was undertaken to determine if high temperature and high pH interact synergistically to enhance the rate of destruction of two important gram-negative foodborne pathogens, Escherichia coli O157:H7 and Salmonella enteritidis. The rates of destruction in NaHCO3-NaOH buffers at pH 7.0, 10.0, and 11.0 were determined at 35, 40, 45, 50, 55, 60, and 65°C. Use of an improved heating protocol eliminated a “tailing effect” at longer exposure times. The present study demonstrated that the combination of high pH and high temperature resulted in a highly significant synergistic interaction (P > F = 0.0001), which caused rapid death of both E. coli O157:H7 and S. enteritidis. This “alka-therm” technology might be used commercially to destroy gram-negative foodborne pathogens on various raw agricultural commodities.

Trisodium Phosphate Increases Sensitivity of Gram-Negative Bacteria to Lysozyme and Nisin

1998 ◽  
Vol 61 (7) ◽  
pp. 839-843 ◽  
Author(s):  
ALEXANDRA M. S. CARNEIRO DE MELO ◽  
CLAIRE A. CASSAR ◽  
ROGER J. MILES
Keyword(s):  
Salmonella Enteritidis ◽  
Viable Count ◽  
Trisodium Phosphate ◽  
Gram Negative Bacteria ◽  
Experimental Conditions ◽  
Gram Negative ◽  
E Coli ◽  
Chicken Skin ◽  
Sublethal Concentrations ◽  
Increased Susceptibility

Cell suspensions of Campylobacter jejuni, Escherichia coli, Pseudomonas fluorescens, and Salmonella enteritidis exposed to sublethal concentrations (0.5 to 5 mM) of trisodium phosphate (TSP) for 10 min showed greatly increased susceptibility to lysozyme (10 μg ml−1) and/or nisin (1 μM). Under optimal conditions at 37°C, reductions in viable count after 30 min were up to six log cycles. At 4°C, C. jejuni showed greater resistance than at 37°C, and maximal cell kills (95%) were reduced by more than two log cycles. Cells dried on the surface of chicken skin were more resistant than suspended cells to TSP–lysozyme and TSP–nisin treatments; nevertheless, at 37°C, kills varied from approximately 95% for S. enteritidis cells with nisin (30 μM) or lysozyme (100 μg ml−1) to >99.9% for C. jejuni and E. coli cells with nisin. Under the experimental conditions used, nisin also reduced viable counts of skin-attached Staphylococcus aureus by >99.9%. The results suggest that the high TSP concentrations (approximately 10% wt/vol, 0.25 M) needed for successful decontamination of gram-negative bacteria, on the surface of poultry and other foodstuffs, may be substantially reduced by following TSP treatment with exposure to low lysozyme or nisin concentrations.

Control of Escherichia coli O157:H7 with Sodium Metasilicate

2004 ◽  
Vol 67 (7) ◽  
pp. 1501-1506 ◽  
Author(s):  
GEORGE H. WEBER ◽  
JUDY K. O'BRIEN ◽  
FREDRIC G. BENDER
Keyword(s):  
Escherichia Coli ◽  
Lactic Acid ◽  
Room Temperature ◽  
Sodium Metasilicate ◽  
Antimicrobial Activities ◽  
Intervention Strategies ◽  
Trisodium Phosphate ◽  
Escherichia Coli O157 ◽  
E Coli

Three intervention strategies—trisodium phosphate, lactic acid, and sodium metasilicate—were examined for their in vitro antimicrobial activities in water at room temperature against a three-strain cocktail of Escherichia coli O157:H7 and a three-strain cocktail of “generic” E. coli. Both initial inhibition and recovery of injured cells were monitored. When 3.0% (wt/wt) lactic acid, pH 2.4, was inoculated with E. coli O157:H7 (approximately 6 log CFU/ml), viable microorganisms were recovered after a 20-min exposure to the acid. After 20 min in 1.0% (wt/wt) trisodium phosphate, pH 12.0, no viable E. coli O157:H7 microorganisms were detected. Exposure of E. coli O157:H7 to sodium metasilicate (5 to 10 s) at concentrations as low as 0.6%, pH 12.1, resulted in 100% inhibition with no recoverable E. coli O157:H7. No difference in inhibition profiles was detected between the E. coli O157:H7 and generic strains, suggesting that nonpathogenic strains may be used for in-plant sodium metasilicate studies.

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