Listeria Research Today is a free monthly online journal that collates and summarizes the latest research about Listeria, including details on listeria monocytogenes, listeriosis, symptoms, pregnancy, treatment, food safety.

Fate of foodborne pathogens on green onions and tomatoes by electrolysed water.

Park EJ, Alexander E, Taylor GA, Costa R, Kang DH

Department of Food Science and Human Nutrition, Washington State University, Pullman, WA 99164-6376, USA.

AIMS: To investigate the efficacy of electrolysed water (EW) in killing Escherichia coli O157:H7, Salmonella typhimurium and Listeria monocytogenes on the surfaces of spot-inoculated green onions and tomatoes. METHODS AND RESULTS: Green onions and tomatoes were inoculated with a cocktail of three strains each of E. coli O157:H7, Salm. typhimurium and L. monocytogenes and treated with acidic electrolysed water (AC-EW), alkaline electrolysed water (AK-EW), alkaline electrolysed water followed by acidic electrolysed water (AK-EW + AC-EW), deionized water followed by acidic electrolysed water (DW + AC-EW) and deionized water (control, DW) for 15 s, 30 s, 1 min, 3 min and 5 min at room temperature (22 +/- 2 degrees C). The relative efficacy of reduction was AC-EW > DW + AC-EW approximately AK-EW + AC-EW > AK-EW > DW. CONCLUSIONS: Acidic EW treatment was able to significantly reduce populations of the three tested pathogens from the surfaces of green onions and tomatoes with increasing exposure time. SIGNIFICANCE AND IMPACT OF THE STUDY: Rinsing in acidic EW reveals an effective method to control the presence of E. coli O157:H7, Salm. typhimurium and L. monocytogenes on the surfaces of fresh green onions and tomatoes, without affecting their organoleptic characteristics. This indicates its potential application for the decontamination of fresh produce surfaces.

Published 17 April 2008 in Lett Appl Microbiol, 46(5): 519-25.
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Articles on Listeria published 17 April 2008:

Sequential exposure to carbon nanotubes and bacteria enhances pulmonary inflammation and infectivity.   Am J Respir Cell Mol Biol, 38(5): 579-90.

Carbon nanotubes (CNT), with their applications in industry and medicine, may lead to new risks to human health. CNT induce a robust pulmonary inflammation and oxidative stress in rodents. Realistic exposures to CNT may occur in conjunction with other pathogenic impacts (microbial infections) and trigger enhanced responses. We evaluated interactions between pharyngeal aspiration of single-walled CNT (SWCNT) and bacterial pulmonary infection of C57BL/6 mice with Listeria monocytogenes (LM). Mice ... [Abstract] [Full-text]

Articles on Listeria published 15 April 2008:

Type I IFN are host modulators of strain-specific Listeria monocytogenes virulence.   Cell Microbiol, 10(5): 1116-29.

Type I IFN (IFN-I) increase the sensitivity of cells and mice to lethal infection with Listeria monocytogenes. Therefore the amount of IFN-I produced during infection might be an important factor determining Listeria virulence. Two commonly used strains of L. monocytogenes, EGD and LO28, were identified as, respectively, low and high inducers of IFN-I synthesis in infected macrophages. Increased IFN-I production resulted from the stronger ability of the LO28 strain to trigger the IRF3 ... [Abstract] [Full-text]

Articles on Listeria published 8 April 2008:

Inhibition of ROCK activity allows InlF-mediated invasion and increased virulence of Listeria monocytogenes.   Mol Microbiol, 68(3): 749-67.

Listeria monocytogenes is an intracellular bacterial pathogen that causes life-threatening disease. The mechanisms used by L. monocytogenes to invade non-professional phagocytic cells are not fully understood. In addition to the requirement of bacterial determinants, host cell conditions profoundly influence infection. Here, we have shown that inhibition of the RhoA/ROCK pathway by pharmacological inhibitors or RNA interference results in increased L. monocytogenes invasion of murine ... [Abstract] [Full-text]

Articles on Listeria published 4 April 2008:

Prophages in Listeria monocytogenes contain single-nucleotide polymorphisms that differentiate outbreak clones within epidemic clones.   J Clin Microbiol, 46(4): 1478-84.

A fragment end ligation-mediated PCR strategy was used to analyze the AscI pulsed-field gel electrophoresis patterns of Listeria monocytogenes epidemic clone II (ECII), which led to the identification of single-nucleotide polymorphisms (SNPs) in prophage regions that differentiated the two ECII outbreak clones. SNPs in prophages that differentiated the outbreak clones of ECIII and -IV were also identified. [Abstract] [Full-text]

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Articles on Listeria published 3 April 2008:

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We report on the crystal structure of the internalin domain of InlJ, a virulence-associated surface protein of Listeria monocytogenes, at 2.7-A resolution. InlJ is a member of the internalin family of listerial cell surface proteins characterized by a common N-terminal domain. InlJ bears 15 leucine-rich repeats (LRRs), the same number as in InlA, the prototypical internalin family member. The LRRs of InlJ differ from those of other internalins by having 21, rather than 22, residues and by ... [Abstract] [Full-text]

Articles on Listeria published 21 March 2008:

Edible chitosan films on ready-to-eat roast beef for the control of Listeria monocytogenes.   Food Microbiol, 25(3): 534-7.

The use of chitosan as an edible film was evaluated for its antimicrobial activity against Listeria monocytogenes (LM) on the surface of ready-to-eat (RTE) roast beef. L. monocytogenes, decimally diluted to give an initial inoculation of >6.50logCFU/g, was inoculated onto the surface of RTE roast beef cubes, and air-dried. The samples were dipped into chitosan (high or low molecular weights) solutions dissolved with acetic or lactic acid at 0.5% (w/v) or 1% (w/v) then bagged and refrigerated ... [Abstract] [Full-text]

Combination of high-intensity pulsed electric fields with natural antimicrobials to inactivate pathogenic microorganisms and extend the shelf-life of melon and watermelon juices.   Food Microbiol, 25(3): 479-91.

The effect of high-intensity pulsed electric field (HIPEF) combined with citric acid (0.5-2.0%, w/v) or cinnamon bark oil (0.05-0.30%, w/v) against populations of Escherichia coli O157:H7, Salmonella Enteritidis and Listeria monocytogenes in melon and watermelon juices were evaluated. Microbiological shelf-life and sensory attributes were also determined. Populations of E. coli O157:H7, S. Enteritidis and L. monocytogenes were reduced by more than 5.0log(10)CFU/ml in HIPEF-processed melon ... [Abstract] [Full-text]

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