Prevalence and level of Listeria monocytogenes and other Listeria sp. in ready-to-eat minimally processed and refrigerated vegetables

2012 ◽  
Vol 29 (4) ◽  
pp. 707-712 ◽  
Author(s):  
Mira Kovačević ◽  
Jelena Burazin ◽  
Hrvoje Pavlović ◽  
Mirela Kopjar ◽  
Vlasta Piližota
Keyword(s):  
Listeria Monocytogenes ◽  
Minimally Processed

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.

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.

Radiation Processing To Ensure Safety of Minimally Processed Carrot (Daucus carota) and Cucumber (Cucumis sativus): Optimization of Dose for the Elimination of Salmonella Typhimurium and Listeria monocytogenes

2006 ◽  
Vol 69 (2) ◽  
pp. 444-448 ◽  
Author(s):  
V. S. DHOKANE ◽  
S. HAJARE ◽  
R. SHASHIDHAR ◽  
A. SHARMA ◽  
J. R. BANDEKAR
Keyword(s):  
Listeria Monocytogenes ◽  
Salmonella Typhimurium ◽  
Escherichia Coli O157 ◽  
Radiation Processing ◽  
Minimally Processed ◽  
Shigella Species ◽  
Storage Studies ◽  
D Values ◽  
Minimally Processed Vegetables ◽  
Control Samples

Minimally processed vegetables are in demand, because they offer convenience to consumers. However, these products are often unsafe because of possible contamination with pathogens, such as Salmonella, Escherichia coli O157:H7, and Shigella species. Therefore, this study was carried out to optimize the radiation dose necessary to ensure the safety of precut carrot and cucumber. Decimal reduction doses (D-values) of Salmonella Typhimurium MTCC 98 were ca. 0.164 kGy in carrot samples and 0.178 kGy in cucumber samples. D-values of Listeria monocytogenes were determined to be 0.312 and 0.345 kGy in carrot and cucumber samples, respectively. Studies of inoculated, packaged, minimally processed carrot and cucumber samples showed that treatment with a 1-kGy dose of gamma radiation eliminated up to 4 log CFU/g of Salmonella Typhimurium and 3 log CFU/g of L. monocytogenes. However, treatment with a 2-kGy dose was necessary to eliminate these pathogens by 5 log CFU/g. Storage studies showed that both Salmonella Typhimurium and L. monocytogenes were able to grow at 10°C in inoculated control samples. Neither of these pathogens could be recovered from radiation-processed samples after storage for up to 8 days.

Control of Listeria monocytogenes by Monoglycerides in Foods

1997 ◽  
Vol 60 (2) ◽  
pp. 131-138 ◽  
Author(s):  
LIH-LING WANG ◽  
ERIC A. JOHNSON
Keyword(s):  
Antimicrobial Activity ◽  
Lactic Acid ◽  
Listeria Monocytogenes ◽  
Culture Media ◽  
Cottage Cheese ◽  
Minimally Processed ◽  
Chemical Factors ◽  
Lipid Compounds ◽  
Camembert Cheese ◽  
Increased Activity

Monoglycerides (MCs) including MC10, MC12, and coconut MCs were tested for inhibitory activity against Listeria monocytogenes strain Scott A in culture media and in several foods. MCs were inhibitory to L. monocytogenes in certain foods including beef frank slurries (pH 5.0 and 5.5) and seafood salad (pH 4.9) at 4°C, but were less active at 12 than at 4°C. MCs were less inhibitory to L. monocytogenes in other foods tested including turkey frank slurries (pH 5.5), imitation crabmeat, cooked shrimp, summer sausage, yogurt, cottage cheese, and Camembert cheese. Combinations of MCs, particularly MC10 and MC12, showed increased activity in certain foods. The combination of MC10 (250 to 500 μg/ml) and MC12 (250 to 500 μg/ml) or a mixture of coconut-derived MCs (500 to 1,000 μg/ml) were inhibitory against L. monocytogenes in beef and turkey frank slurries. Certain Chemical factors affected the degree of inhibition by the lipid compounds including pH, acidulants such as lactic acid, certain antioxidants, and lipid carriers. The results suggest that MCs could be used as preservatives in certain classes of minimally processed refrigerated foods when intrinsic antimicrobial activity is inadequate.

scholarly journals Effects of Epiphytic Enterobacteriaceae and Pseudomonads on the Growth of Listeria monocytogenes in Model Media

2001 ◽  
Vol 64 (5) ◽  
pp. 721-724 ◽  
Author(s):  
J. DEL CAMPO ◽  
F. CARLIN ◽  
C. NGUYEN-THE
Keyword(s):  
Amino Acids ◽  
Listeria Monocytogenes ◽  
Yeast Extract ◽  
Inhibitory Activity ◽  
Minimal Medium ◽  
Pseudomonas Chlororaphis ◽  
Enterobacter Agglomerans ◽  
Minimally Processed ◽  
Yeast Extract Medium ◽  
Extract Medium

Four Enterobacteriaceae (Enterobacter agglomerans and Rhanella aquatilis) and six pseudomonads (Pseudomonas fluorescens, Pseudomonas chlororaphis, Pseudomonas putida) isolated from minimally processed green endive were coinoculated at 10°C with Listeria monocytogenes in a minimal medium. Pseudomonads did not modify the growth of L. monocytogenes, whereas Enterobacteriaceae reduced its maximal population by 2 to 3 log CFU/ml. The same effect was observed in a diluted yeast extract medium supplemented with amino acids and glucose, in which L. monocytogenes grown alone reached 109 to 1010 CFU/ml. In the same diluted yeast extract medium, not supplemented with glucose and amino acids, the maximal population of L. monocytogenes in the presence of both Enterobacteriaceae and pseudomonads was only slightly reduced (less than 0.5 log CFU/ml). Culture filtrates of the Enterobacteriaceae had no inhibitory activity on L. monocytogenes. The effect of the Enterobacteriaceae on L. monocytogenes growth was presumably due to a competition for glucose and/or amino acids.

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.

scholarly journals Listeria monocytogenes: A CONSIDERABLE PATHOGENIC MICROORGANISM OF CONCERN IN MINIMALLY PROCESSED FRUITS AND VEGETABLES

2017 ◽  
Vol 6 (1) ◽  
pp. 1
Author(s):  
Helen C D Tuhumury
Keyword(s):  
Listeria Monocytogenes ◽  
Foodborne Pathogens ◽  
Fruits And Vegetables ◽  
Significant Risk ◽  
Pathogenic Microorganism ◽  
Minimally Processed ◽  
Growth And Survival ◽  
Food Borne ◽  
Increasing Demand

The increasing demand of minimally processed fruits and vegetables signify a challenge to make them stable and safe to be consumed. The processing of this type of product may contribute higher risks of food borne illnesses. One of the foodborne pathogens in minimally processed fruits and vegetables is Listeria monocytogenes. The importance of understanding the characteristics of L. monocytogenes will help to determine how this microorganism occurs, grows, and survives in minimally processed fruits and vegetables. Proper and suitable methods to reduce L. monocytogenes so that it can not pose a significant risk to cause disease therefore are able to be determined according to the model of the growth and survival of L. monocytogenes in minimally processed fruits and vegetables.

Influence of Background Microflora on Listeria monocytogenes on Minimally Processed Fresh Broad-Leaved Endive (Cichorium endivia var. latifolia)

1996 ◽  
Vol 59 (7) ◽  
pp. 698-703 ◽  
Author(s):  
FREDERIC CARLIN ◽  
CHRISTOPHE NGUYEN-THE ◽  
CINDY E. MORRIS
Keyword(s):  
Listeria Monocytogenes ◽  
Bacterial Population ◽  
Maximum Growth ◽  
Minimally Processed ◽  
Cichorium Endivia ◽  
Sterile Medium ◽  
Leaf Exudate ◽  
Chemical Disinfection

Interactions between Listeria monocytogenes and the background microflora of endive leaves was studied by (i) testing the effect of disinfecting endive leaves on the fate of L. monocytogenes, and (ii) challenging L. monocytogenes along with each of 10 strains of pseudomonads and Enterobacteriaceae isolated from endive leaves on both leaves of endive and in a model sterile medium based on an exudate of endive leaf. There was a higher increase in the population of L. monocytogenes on endive leaves with a background microflora reduced by a chemical disinfection. High numbers (106 to 107 CFU/g) of some strains reduced the growth of L. monocytogenes on endive. None of the 10 strains tested promoted the growth of L. monocytogenes. In the medium made of endive leaf exudate, the 10 strains tested reduced the maximum growth of L. monocytogenes to extents that varied with the strains. A complex bacterial population extracted from endive leaves completely inhibited the growth of L. monocytogenes in the medium.

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