Effect of Gamma Radiation on the Reduction of Salmonella strains, Listeria monocytogenes, and Shiga Toxin–Producing Escherichia coli and Sensory Evaluation of Minimally Processed Spinach (Tetragonia expansa)

2014 ◽  
Vol 77 (10) ◽  
pp. 1768-1772 ◽  
Author(s):  
ANA CAROLINA B. REZENDE ◽  
MARIA CRYSTINA IGARASHI ◽  
MARIA TERESA DESTRO ◽  
BERNADETTE D. G. M. FRANCO ◽  
MARIZA LANDGRAF
Keyword(s):  
Escherichia Coli ◽  
Listeria Monocytogenes ◽  
Gamma Radiation ◽  
Shiga Toxin ◽  
Radiation Doses ◽  
Minimally Processed ◽  
Tetragonia Expansa ◽  
Effects Of Irradiation On ◽  
Spinach Leaves

This study evaluated the effects of irradiation on the reduction of Shiga toxin–producing Escherichia coli (STEC), Salmonella strains, and Listeria monocytogenes, as well as on the sensory characteristics of minimally processed spinach. Spinach samples were inoculated with a cocktail of three strains each of STEC, Salmonella strains, and L. monocytogenes, separately, and were exposed to gamma radiation doses of 0, 0.2, 0.4, 0.6, 0.8, and 1.0 kGy. Samples that were exposed to 0.0, 1.0, and 1.5 kGy and kept under refrigeration (4°C) for 12 days were submitted to sensory analysis. D10-values ranged from 0.19 to 0.20 kGy for Salmonella and from 0.20 to 0.21 for L. monocytogenes; for STEC, the value was 0.17 kGy. Spinach showed good acceptability, even after exposure to 1.5 kGy. Because gamma radiation reduced the selected pathogens without causing significant changes in the quality of spinach leaves, it may be a useful method to improve safety in the fresh produce industry.

SOME EFFECTS OF GAMMA RADIATION ON THE STORAGE LIFE OF FRESH STRAWBERRIES

1964 ◽  
Vol 44 (2) ◽  
pp. 188-194 ◽  
Author(s):  
H. B. Heeney ◽  
W. M. Rutherford ◽  
K. F. MacQueen
Keyword(s):  
Gamma Radiation ◽  
Storage Period ◽  
Storage Life ◽  
Radiation Doses ◽  
Apparent Effect ◽  
Fungal Development ◽  
Radiation Treatments ◽  
Storage Temperatures

The effects of gamma radiation doses of 110,000, 220,000, and 330,000 rad on the storage life and quality of two varieties of strawberries stored at 40°, 55°, and 70° F were studied. Results indicated that a dose of 330,000 rad prevented fungal development of the Redcoat variety stored for 26 days at 40° F. The fungal-free period was sharply reduced at lower radiation doses or at higher storage temperatures. Under the conditions of this trial there was no apparent effect of radiation on appearance or texture of fruit.In organoleptic tests in the first two weeks of storage observers were not able to differentiate between radiation treatments. There was some preference for treated berries as the storage period increased. After 20 days the flavor of the fruit deteriorated very rapidly and it soon became commercially unacceptable.

Comparison of Four Commercial DNA Extraction Kits for PCR Detection of Listeria monocytogenes, Salmonella, Escherichia coli O157:H7, and Staphylococcus aureus in Fresh, Minimally Processed Vegetables

2008 ◽  
Vol 71 (10) ◽  
pp. 2110-2114 ◽  
Author(s):  
P. ELIZAQUÍVEL ◽  
R. AZNAR
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Listeria Monocytogenes ◽  
Dna Extraction ◽  
Pcr Detection ◽  
Escherichia Coli O157 ◽  
Minimally Processed ◽  
Green Pepper ◽  
Minimally Processed Vegetables ◽  
And Staphylococcus Aureus

Four commercial DNA extraction methods, PrepMan Ultra (Applied Biosystems), InstaGene Matrix (BioRad), DNeasy Tissue kit (Qiagen), and UltraClean (MoBio), were tested for PCR detection of Listeria monocytogenes, Escherichia coli O157: H7, Salmonella, and Staphylococcus aureus in fresh, minimally processed vegetables. For comparative purposes, sensitivity assays with specific PCRs were carried out after DNA extraction with the four methods in green pepper, broccoli, and onion artificially inoculated with the four pathogens separately. As confirmed by statistical analysis, the DNeasy Tissue kit rendered the highest sensitivity values in the three matrices assayed for Salmonella, L. monocytogenes, and E. coli O157:H7 and in onion for S. aureus. Despite being the most expensive of the methods compared, the DNeasy Tissue Kit can be successfully applied for any of the four most commonly studied pathogens, thus saving time and overall reducing the cost of the analysis.

Validation of D- and Z-values for Listeria monocytogenes, Salmonella and Shiga-toxin producing Escherichia coli in ready-to-eat meat and poultry products

Meat Science ◽  
2014 ◽  
Vol 96 (1) ◽  
pp. 484-485 ◽  
Author(s):  
A.M. King ◽  
R.P. McMinn ◽  
J.J. Sindelar ◽  
K.A. Glass ◽  
A.L. Milkowski ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Listeria Monocytogenes ◽  
Shiga Toxin ◽  
Poultry Products

Microbiological Quality of Retail Imported Unprepared Whole Lettuces: A PHLS Food Working Group Study

1999 ◽  
Vol 62 (4) ◽  
pp. 325-328 ◽  
Author(s):  
C. LITTLE ◽  
D. ROBERTS ◽  
E. YOUNGS ◽  
J. de LOUVOIS
Keyword(s):  
Escherichia Coli ◽  
Listeria Monocytogenes ◽  
Microbiological Quality ◽  
Escherichia Coli O157 ◽  
Salmonella Spp ◽  
Shigella Spp ◽  
Natural Microflora ◽  
Production Practices ◽  
Campylobacter Spp

A study of imported unprepared whole lettuces sampled from supermarkets, greengrocers, shops, and market stalls found that all were of acceptable microbiological quality. Twenty-seven out of 151 (18%) imported lettuce samples had Enterobacteriaceae levels of 104 CFU/g or more. However, these bacteria that constitute part of the natural microflora of unprepared vegetables may also be derived from the soil and/or by poor handling. The pathogens, Salmonella spp., Shigella spp., Campylobacter spp., Escherichia coli O157:H7, Vibrio cholerae, Listeria monocytogenes, and also Escherichia coli, an indicator of fecal contamination, were not detected in any imported lettuces, indicating that hygiene, harvesting, and production practices were good. Imported lettuces with Enterobacteriaceae levels of 104 CFU/g or more varied with type of retail premises and the temperature at which the lettuces were displayed. Samples from greengrocers, shops, and market stalls were more likely to contain Enterobacteriaceae at levels in excess of 104 CFU/g than those from supermarkets.

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

Survival and Growth of Listeria monocytogenes and Enterohemorrhagic Escherichia coli O157:H7 in Minimally Processed Artichokes

2003 ◽  
Vol 66 (12) ◽  
pp. 2203-2209 ◽  
Author(s):  
SUSANA SANZ ◽  
MERCEDES GIMÉNEZ ◽  
CARMEN OLARTE
Keyword(s):  
Escherichia Coli ◽  
Listeria Monocytogenes ◽  
Tap Water ◽  
Storage Period ◽  
Enterohemorrhagic Escherichia Coli ◽  
Fecal Coliforms ◽  
Escherichia Coli O157 ◽  
Natural Background ◽  
Minimally Processed ◽  
E Coli

The ability of Listeria monocytogenes and Escherichia coli O157:H7 inoculated by immersion (at 4.6 and 5.5 log CFU/g, respectively) to survive on artichokes during various stages of preparation was determined. Peeling, cutting, and disinfecting operations (immersion in 50 ppm of a free chlorine solution at 4°C for 5 min) reduced populations of L. monocytogenes and E. coli O157:H7 by only 1.6 and 0.8 log units, respectively. An organic acid rinse (0.02% citric acid and 0.2% ascorbic acid) was more effective than a tap water rinse in removing these pathogens. Given the possibility of both pathogens being present on artichokes at the packaging stage, their behavior during the storage of minimally processed artichokes was investigated. For this purpose, batches of artichokes inoculated with L. monocytogenes or E. coli O157:H7 (at 5.5 and 5.2 log CFU/g, respectively) were packaged in P-Plus film bags and stored at 4°C for 16 days. During this period, the equilibrium atmosphere composition and natural background microflora (mesophiles, psychrotrophs, anaerobes, and fecal coliforms) were also analyzed. For the two studied pathogens, the inoculum did not have any effect on the final atmospheric composition (10% O2, 13% CO2) or on the survival of the natural background microflora of the artichokes. L. monocytogenes was able to survive during the entire storage period in the inoculated batches, while the E. coli O157:H7 level increased by 1.5 log units in the inoculated batch during the storage period. The modified atmosphere was unable to control the behavior of either pathogen.

Effect of UV-C radiation on quality of minimally processed spinach leaves

2009 ◽  
Vol 89 (3) ◽  
pp. 414-421 ◽  
Author(s):  
Francisco Artés-Hernández ◽  
Víctor Hugo Escalona ◽  
Pedro Antonio Robles ◽  
Ginés Benito Martínez-Hernández ◽  
Francisco Artés
Keyword(s):  
Minimally Processed ◽  
Uv C ◽  
Spinach Leaves

scholarly journals Complete Genome Sequence of a Shiga Toxin-Producing Escherichia coli O26:H11 Strain (Sequence Type 21) and Two Draft Genome Sequences of Listeria monocytogenes Strains (Clonal Complex 1 [CC1] and CC59) Isolated from Fresh Produce in Germany

2020 ◽  
Vol 9 (49) ◽  
Author(s):  
Gregor Fiedler ◽  
Jan Kabisch ◽  
Erik Brinks ◽  
Sabrina Sprotte ◽  
Christina Boehnlein ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Listeria Monocytogenes ◽  
Shiga Toxin ◽  
Complete Genome Sequence ◽  
Complete Genome ◽  
Clonal Complex ◽  
Draft Genome ◽  
Sequence Type ◽  
Genome Sequences ◽  
Content Type

ABSTRACT The complete genome sequence of a Shiga toxin-producing Escherichia coli (STEC) O26:H11 strain, MBT-5 (sequence type 21 [ST21], stx1a, stx2a, eae, ehxA), and two draft genome sequences of Listeria monocytogenes strains MBT-6 and MBT-7 belonging to the virulent sequence types 1 (ST1, clonal complex 1 [CC1]) and 59 (ST59, CC59), respectively, were determined. The strains were isolated in 2015 from ready-to-eat mixed greens in Germany.

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