scholarly journals Bactericidal activity of lauric arginate in milk and Queso Fresco cheese against Listeria monocytogenes cold growth

2010 ◽  
Vol 93 (10) ◽  
pp. 4518-4525 ◽  
Author(s):  
K.A. Soni ◽  
R. Nannapaneni ◽  
M.W. Schilling ◽  
V. Jackson
Keyword(s):  
Listeria Monocytogenes ◽  
Bactericidal Activity ◽  
Lauric Arginate

scholarly journals THE ENHANCEMENT OF MACROPHAGE BACTERIOSTASIS BY PRODUCTS OF ACTIVATED LYMPHOCYTES

1973 ◽  
Vol 138 (4) ◽  
pp. 952-964 ◽  
Author(s):  
Robert E. Fowles ◽  
Ileana M. Fajardo ◽  
Jacques L. Leibowitch ◽  
John R. David
Keyword(s):  
Listeria Monocytogenes ◽  
Guinea Pig ◽  
Concanavalin A ◽  
Bactericidal Activity ◽  
Culture Supernatant ◽  
Cell Adherence ◽  
Activated Lymphocytes ◽  
Glucose Carbon ◽  
Lymphocyte Cultures ◽  
By Products

It was reported previously that the incubation of normal guinea pig macrophages with partially purified products of activated lymphocytes resulted in altered macrophage function including increased cell adherence to culture vessels, spreading, phagocytosis, and glucose carbon-1 oxidation. Studies reported here demonstrate that such macrophages also exhibit enhanced bacteriostasis. Lymphocytes were stimulated with concanavalin A, the culture supernatant was chromatographed over Sephadex G-100 and the fraction of mol wt 25,000–55,000, rich in lymphocyte mediators, was cultured with normal guinea pig macrophages for 1–3 days. Macrophages incubated with fractions from unstimulated lymphocyte cultures served as controls. The resulting macrophage monolayers were infected with Listeria monocytogenes. Macrophages incubated with mediator-rich fractions exhibited 2- to 10-fold enhanced bacteriostasis compared to controls. Further studies indicate that this enhancement was attributable to intrinsic changes in the macrophages and not simply a consequence of the number of macrophages on the monolayers. The studies support the concept that macrophage bacteriostasis can be enhanced by lymphocyte mediators. However, macrophages, which have been preincubated directly with sensitive lymphocytes and antigen exhibit even greater bacteriostasis and sometimes bactericidal capacity, suggesting that either a labile lymphocyte factor or direct lymphocyte macrophage interaction may also be involved in bactericidal activity.

Inactivation of Pathogenic Bacteria by Cucumber Volatiles (E,Z)-2,6-Nonadienal and (E)-2-Nonenal†

2004 ◽  
Vol 67 (5) ◽  
pp. 1014-1016 ◽  
Author(s):  
M. J. CHO ◽  
R. W. BUESCHER ◽  
M. JOHNSON ◽  
M. JANES
Keyword(s):  
Escherichia Coli ◽  
Listeria Monocytogenes ◽  
Salmonella Typhimurium ◽  
Bactericidal Activity ◽  
Pathogenic Bacteria ◽  
Brain Heart Infusion ◽  
Escherichia Coli O157 ◽  
Infusion Solution ◽  
E Coli ◽  
Log Reduction

The effects of (E,Z)-2,6-nonadienal (NDE) and (E)-2-nonenal (NE) on Bacillus cereus, Escherichia coli O157:H7, Listeria monocytogenes, and Salmonella Typhimurium were investigated. A suspension of each organism of 6 to 9 log CFU/ml was incubated for 1 h at 37° C in brain heart infusion solution that contained 0 to 500 or 1,000 ppm of NDE or NE. Depending on concentration, exposure to either NDE or NE caused a reduction in CFU of each organism. Treatment with 250 and 500 ppm NDE completely eliminated viable B. cereus and Salmonella Typhimurium cells, respectively. L. monocytogenes was the most resistant to NDE, showing only about a 2-log reduction from exposure to 500 ppm for 1 h. Conversely, this concentration of NDE caused a 5.8-log reduction in E. coli O157:H7 cells. NE was also effective in inactivating organisms listed above. A higher concentration of NE, 1,000 ppm, was required to kill E. coli O157:H7, L. monocytogenes, or Salmonella Typhimurium compared with NDE. In conclusion, both NDE and NE demonstrated an apparent bactericidal activity against these pathogens.

Efficacy of Antimicrobials Applied Individually and in Combination for Controlling Listeria monocytogenes as Surface Contaminants on Queso Fresco

2017 ◽  
Vol 81 (1) ◽  
pp. 46-53 ◽  
Author(s):  
Sarah M. Kozak ◽  
Yustyna Bobak ◽  
Dennis J. D'Amico
Keyword(s):  
Listeria Monocytogenes ◽  
Calcium Sulfate ◽  
Sterile Water ◽  
Water Control ◽  
Log Reduction ◽  
Synergistic Interactions ◽  
Surface Contaminants ◽  
Lauric Arginate ◽  
Sodium Caprylate ◽  
Process Controls

ABSTRACT Outbreaks of listeriosis are continually attributed to the consumption of Hispanic-style soft cheeses contaminated with Listeria monocytogenes postpasteurization. Once contaminated, L. monocytogenes can grow rapidly in cheeses like Queso Fresco (QF) even when stored at refrigeration temperatures. Several antimicrobials, including acidified calcium sulfate with lactic acid (ACSL), ɛ-polylysine (EPL), hydrogen peroxide (HP), lauric arginate ethyl ester (LAE), and sodium caprylate (SC), have demonstrated antilisterial activity in food. The objectives of this study were to determine the efficacy of these antimicrobials used individually and in combination to control L. monocytogenes as surface contaminants on QF and to identify additive and synergistic interactions. Cheeses were surface inoculated at ∼4 log CFU/g, dipped in antimicrobial solutions, vacuum packaged, and then stored at 7°C for 35 days. L. monocytogenes counts were determined 24 h after application of the antimicrobials and then weekly throughout storage. Dip treatments in a 5% (v/v) HP solution reduced L. monocytogenes counts to <0.5 log CFU/g within 24 h with no increase in counts through day 35. Dip treatments in LAE at 2 and 5% alone and in combination with EPL at 10% produced initial reductions in pathogen counts (1.5 to 1.8 CFU/g) but did not inhibit pathogen growth compared with the sterile water control. Dip applications of ACSL at 25% also produced an initial ∼1.5-log reduction in L. monocytogenes counts followed by regrowth. Application of SC at 10% alone and in combination with either EPL or LAE inhibited growth to <1 log CFU/g through 21 days of storage. The combination of ACSL+SC worked synergistically to inhibit the growth of L. monocytogenes on QF to <1 log CFU/g through 35 days. These data indicate that HP alone and treatments containing EPL, LAE, or ACSL in combination with SC are promising postlethality treatments and process controls for L. monocytogenes on QF through a 21-day shelf life.

Comparative Efficacy of Potassium Levulinate with and without Potassium Diacetate and Potassium Propionate versus Potassium Lactate and Sodium Diacetate for Control of Listeria monocytogenes on Commercially Prepared Uncured Turkey Breast†

2015 ◽  
Vol 78 (5) ◽  
pp. 927-933 ◽  
Author(s):  
ANNA C. S. PORTO-FETT ◽  
STEPHEN G. CAMPANO ◽  
BRADLEY A. SHOYER ◽  
DAVID ISRAELI ◽  
ALAN OSER ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Refrigerated Storage ◽  
Target Level ◽  
Comparative Efficacy ◽  
Storage Product ◽  
Potassium Lactate ◽  
Lauric Arginate ◽  
Product Surface ◽  
Sodium Diacetate

We evaluated the efficacy of potassium levulinate (KLEV; 0.0, 1.0, 1.5, and 2.0%) with and without a blend of potassium propionate (0.1%) and potassium diacetate (0.1%) (KPD) versus a blend of potassium lactate (1.8%) and sodium diacetate (0.125%) (KLD) for inhibiting Listeria monocytogenes on commercially prepared, uncured turkey breast during refrigerated storage. Product formulated with KLD or KLEV (1.5%) was also subsequently surface treated with 44 ppm of a solution of lauric arginate (LAE). Slices (ca. 1.25 cm thick and 100 g) of turkey breast formulated with or without antimicrobials were surface inoculated on both the top and bottom faces to a target level of ca. 3.5 log CFU per slice with a five-strain cocktail of L. monocytogenes, vacuum sealed, and then stored at 4°C for up to 90 days. Without inclusion of antimicrobials in the formulation, pathogen levels increased by ca. 5.2 log CFU per slice, whereas with the inclusion of 1.0 to 2.0% KLEV pathogen levels increased by only ca. 2.9 to 0.8 log CFU per slice after 90 days at 4°C. When 1.0% KLEV and KPD were included as ingredients, pathogen levels increased by ca. 0.8 log CFU per slice after storage at 4°C for 90 days, whereas a decrease of ca. 0.7 log CFU per slice was observed when 1.5 or 2.0% KLEV and KPD were included as ingredients. When used alone, KPD was not effective (≥5.8-log increase). As expected, KLD was effective at suppressing L. monocytogenes in uncured turkey breast. When uncured turkey breast was formulated with KLD or KLEV (1.5%) or without antimicrobials and subsequently surface treated with LAE, pathogen levels decreased by ca. 1.0 log CFU per package within 2 h; no differences (P ≥ 0.01) were observed in pathogen levels for product surface treated with or without LAE and stored for 90 days. Our results validate the use of KLEV to inhibit outgrowth of L. monocytogenes during refrigerated storage of uncured turkey breast. KLEV is at least as effective as KLD as an antilisterial agent.

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