Listeria monocytogenes: A Model System for Studying Autophagy

2006 ◽  
pp. 161-178
Author(s):  
Kathryn A. Rich ◽  
Paul Webster
Keyword(s):  
Listeria Monocytogenes ◽  
Model System

scholarly journals Resistance of Listeria monocytogenes biofilms to disinfectants 326

2010 ◽  
Vol 28 (No. 4) ◽  
pp. 326-332 ◽  
Author(s):  
S. Purkrtová ◽  
H. Turoňová ◽  
T. Pilchová ◽  
K. Demnerová ◽  
J. Pazlarová
Keyword(s):  
Listeria Monocytogenes ◽  
Reference Strain ◽  
Model Organism ◽  
Model System ◽  
Optimal Conditions ◽  
Microtiter Plates ◽  
Peptone Water ◽  
Optimal Values ◽  
Biofilm Development ◽  
Chloride Treatment

We studied the optimal conditions for the biofilm development by Listeria monocytogenes on a model system represented by microtiter plates, and also for determined some effective disinfectant agents. Listeria monocytogenes ATCC 13932 and an industrial isolate of Listeria monocytogenes Lm-24 were compared as to their abilities to form biofilms. The starting concentration of the cells leading to the most reproducible results was 0.5 McFarland. The temperatures tested ranged between 8°C to 37°C, the optimal values to form biofilm in buffered peptone water (BPW) with 0.05% glucose were 25°C and 30°C. Under comparable conditions the persistent strain L. monocytogenes Lm-24 constituted more massive biofilm than did the reference strain. The following disinfectants were applied: Savo, Merades Alco, benzalalkonium chloride. A persistent industry in isolate Listeria monocytogenes Lm-24 was used as the model organism for these tests. Benzalalkonium chloride treatment was found to be the most efficient way to damage the biofilm. One minute treatment with 500 mg/l was lethal for the biofilm cells, and that with 125 mg/l for planctonic cells. Savo suppresed the viability of the biofilm cells only by about 20% on average while being lethal for planctonic cells. Merades Alco exhibited only a weak effect on both the biofilm and planctonic cells.

Relationship Between Water Activity, Salts of Lactic Acid, and Growth of Listeria monocytogenes in a Meat Model System

1992 ◽  
Vol 55 (8) ◽  
pp. 574-578 ◽  
Author(s):  
NING CHEN ◽  
LEORA A. SHELEF
Keyword(s):  
Lactic Acid ◽  
Listeria Monocytogenes ◽  
Moisture Content ◽  
Water Activity ◽  
Sodium Lactate ◽  
Model System ◽  
Cell Numbers ◽  
Maximum Cell ◽  
The Relationship ◽  
Control Samples

The relationship between water activity (aw), lactate, and growth of Listeria monocytogenes strain Scott A was studied in a meat model system consisting of cooked strained beef ranging in moisture content from 25 to 85% (wt/wt). Lactate (4%) depressed meat aw, and differences between aw values in control and lactate-treated samples at each moisture level increased progressively with decrease in moisture, from 0.003 (85% moisture) to 0.046 (25% moisture). Maximum cell numbers per g in control samples stored at 20°C for 7 d were about 109 (45–85% moisture, aw= 0.981–0.994) and 107 (35% moisture, aw = 0.965); there was no growth in meat with 25% moisture (aw = 0.932). Sodium lactate (4%) suppressed listerial growth at >55% and inhibited growth in samples with 25–55% moisture (a < 0.964). Lactate concentrations less than 4% were not listeristatic, but combinations of 2 or 3% lactate with 2% NaCl in samples with 55% moisture inhibited growth. Potassium and calcium lactate were as effective as the sodium salt in suppressing growth and aw.

Use of natural antimicrobials to improve the control of Listeria monocytogenes in a cured cooked meat model system

Meat Science ◽  
2011 ◽  
Vol 88 (3) ◽  
pp. 503-511 ◽  
Author(s):  
Y. Xi ◽  
G.A. Sullivan ◽  
A.L. Jackson ◽  
G.H. Zhou ◽  
J.G. Sebranek
Keyword(s):  
Listeria Monocytogenes ◽  
Model System ◽  
Natural Antimicrobials ◽  
Cooked Meat

Bactericidal Effect of Enterocin 4 on Listeria monocytogenes in a Model Dairy System

1997 ◽  
Vol 60 (1) ◽  
pp. 28-32 ◽  
Author(s):  
JOSE L. RODRIGUEZ ◽  
PILAR GAYA ◽  
MARGARITA MEDINA ◽  
MANUEL NUÑEZ
Keyword(s):  
Listeria Monocytogenes ◽  
Enterococcus Faecalis ◽  
Bactericidal Effect ◽  
Model System ◽  
Ewe's Milk

Enterococcus faecalis INIA 4 produced the bacteriocin enterocin 4 during growth in raw ewe's milk at 30°C. Enterocin activity reached 2,200 to 3,600 AU/ml after 8 h, with a 1 to 8% (vol/vol) level of inoculum from an 18-h culture. An enterocin activity of 500 AU/ml significantly decreased counts of Listeria monocytogenes Ohio when incubated for 6 h in a model system consisting of filtrates from cultures of E.faecalis INIA 4 in raw ewe's milk, at pH 6.0 and 30°C. However, an enterocin activity of 2,400 AU/ml was needed in the same conditions to significantly decrease counts of L. monocytogenes Scott A. All 22 wild L. monocytogenes strains isolated from ewe's milk and tested were inhibited by a filtrate containing 400 AU/ml of enterocin 4. Incubation in the filtrate for 6 h significantly lowered counts of 16 L. monocytogenes strains, and incubation for 24 h, counts of 21 strains.

Inhibition of Listeria monocytogenes, Escherichia coli O157:H7, and Micrococcus luteus by Linear Furanocoumarins in a Model Food System

1997 ◽  
Vol 60 (9) ◽  
pp. 1050-1054 ◽  
Author(s):  
JORGE ULATE-RODRÍGUEZ ◽  
H. WILLIAM SCHAFER ◽  
EDMUND A. ZOTTOLA ◽  
P. MICHAEL DAVIDSON
Keyword(s):  
Escherichia Coli ◽  
Listeria Monocytogenes ◽  
Food System ◽  
Micrococcus Luteus ◽  
Model System ◽  
Gas Chromatography Mass Spectrometry ◽  
Escherichia Coli O157 ◽  
Model Food ◽  
Lime Peel ◽  
Cold Pressed

Lime peel, parsnip, lemon peel, dried parsley flakes, cold pressed lime oil, and distilled lime oil samples were analyzed for the presence and concentration of the linear furanocoumarins (LFs) psoralen, 5-methoxypsoralen (5- MOP), and 8-methoxypsoralen (8-MOP) by thin layer chromatography and gas chromatography mass spectrometry. Cold-pressed lime oil had the highest LF content (psoralen, 67 ± 29 μg/ml, 5-MOP, 1,634 ± 62 μg/ml, and 8-MOP, 44 ± 2 μg/ml). The antimicrobial effectiveness of LFs against Listeria monocytogenes, Escherichia coli O157:H7, and Micrococcus luteus was tested in a model food system consisting of a slurry of 25% commercial “garden vegetables” baby food in 0.1% peptone water. Inhibition required UV activation after the addition of the LFs to the model system. Lime peel extract, cold-pressed lime oil, and a 5-MOP standard inhibited the growth of L. monocytogenes, but not E. coli O157:H7. M. luteus was inhibited only by the cold-pressed lime oil. The minimum LF concentration that caused inhibition of the growth of L. monocytogenes was 32 μg/g and the minimum bactericidal concentration was 43 μg/g. Cold-pressed lime oil inhibited L. monocytogenes even at the lowest concentration added to the model system (10 μg/g), while the corresponding LF standard did not. This suggested the presence of other antimicrobial agents in the oil.

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