scholarly journals Survival characteristics of E. coli O157:H7, S. typhimurium and S. aureus during kefir fermentation

2008 ◽  
Vol 25 (No. 4) ◽  
pp. 202-207 ◽  
Author(s):  
N. Karagözlü ◽  
C. Karagözlü ◽  
B. Ergönül
Keyword(s):  
Staphylococcus Aureus ◽  
Salmonella Typhimurium ◽  
Growth And Survival ◽  
E Coli ◽  
Fermentation Period ◽  
Different Levels

In this research, the growth and survival of <i>E. coli</i> O157:H7, <i>Salmonella typhimurium</i> and <i>Staphylococcus aureus</i> were investigated during kefir fermentation. Two different levels of inoculation of the strains were conducted; the levels of 102 CFU/ml (EC-1, SA-1 and S-1) and 103 CFU/ml (EC-2, SA-2 and S-2). At 0, 2, 6, 12, and 24 hours of kefir fermentation at 23 ± 1°C, samples were taken and the counts of <i>E. coli</i> O157:H7, <i>S. typhimurium</i>, and <i>S. aureus</i> were determined. EC-1 grew from 2.29 ± 0.02 log CFU/ml to 4.13 ± 0.18 log CFU/ml whereas EC-2 grew from 3.22 ± 0.04 log CFU/ml to 6.78 ± 0.99 log CFU/ml. Both S-1 and S-2 viable populations grew during the fermentation period, where sample S-1 grew from 2.37 ± 0.20 log CFU/ml to 4.64 ± 0.67 log CFU/ml and sample S-2 grew from 3.52 ± 0.07 log CFU/ml to 5.60 ± 0.10 log CFU/ml. SA-2 strains grew from 3.06 log CFU/ml to 3.64 log CFU/ml, SA-1 strains grew from 2.28 log CFU/ml to 2.66 log CFU/ml. According to the findings, <i>E. coli</i> O157:H7, <i>S. typhimurium</i>, and <i>S. aureus</i> can survive in kefir during fermentation.

scholarly journals ATIVIDADE ANTIMICROBIANA DE MICRORGANISMOS ISOLADOS DE GRÃOS DE KEFIR

2018 ◽  
Vol 19 (0) ◽  
Author(s):  
Priscila Alves Dias ◽  
Daiani Teixeira Silva ◽  
Cláudio Dias Timm
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Listeria Monocytogenes ◽  
Salmonella Typhimurium ◽  
Salmonella Enterica ◽  
Escherichia Coli O157 ◽  
E Coli

Resumo Kefir é o produto da fermentação do leite pelos grãos de kefir. Esses grãos contêm uma mistura simbiótica de bactérias e leveduras imersas em uma matriz composta de polissacarídeos e proteínas. Muitos benefícios à saúde humana têm sido atribuídos ao kefir, incluindo atividade antimicrobiana contra bactérias Gram positivas e Gram negativas. A atividade antimicrobiana de 60 microrganismos isolados de grãos de kefir, frente à Escherichia coli O157:H7, Salmonella enterica subsp. enterica sorotipos Typhimurium e Enteritidis, Staphylococcus aureus e Listeria monocytogenes, foi estudada através do teste do antagonismo. A ação antimicrobiana dos sobrenadantes das bactérias ácido-lácticas que apresentaram atividade no teste do antagonismo foi testada. O experimento foi repetido usando sobrenadantes com pH neutralizado. Salmonella Typhimurium e Enteritidis sobreviveram por 24 horas no kefir em fermentação. E. coli O157:H7, S. aureus e L. monocytogenes foram recuperados até 72 horas após o início da fermentação. Todos os isolados apresentaram atividade antimicrobiana contra pelo menos um dos patógenos usados no teste do antagonismo. Sobrenadantes de 25 isolados apresentaram atividade inibitória e três mantiveram essa atividade com pH neutralizado. As bactérias patogênicas estudadas sobreviveram por tempo superior àquele normalmente utilizado para a fermentação do kefir artesanal, o que caracteriza perigo em potencial para o consumidor quando a matéria-prima não apresentar segurança sanitária. Lactobacillus isolados de grãos de kefir apresentam atividade antimicrobiana contra cepas de E. coli O157:H7, Salmonella sorotipos Typhimurium e Enteritidis, S. aureus e L. monocytogenes além daquela exercida pela diminuição do pH.

Antimicrobial Effects of Novel H2O2-Ag+ Complex on Membrane Damage to Staphylococcus aureus,Escherichia coli and Salmonella typhimurium

2021 ◽  
Author(s):  
Bing Han ◽  
Xiaoyu Han ◽  
Mengmeng Ren ◽  
Yilin You ◽  
Jicheng Zhan ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Hydrogen Peroxide ◽  
Staphylococcus Aureus ◽  
Salmonella Typhimurium ◽  
Membrane Damage ◽  
Bactericidal Effect ◽  
E Coli ◽  
Bacterial Cell Membrane ◽  
Time Kill ◽  
Environmental Disinfection

Diseases caused by harmful microorganisms pose a serious threat to human health. Safe and environment-friendly disinfectants are, therefore, essential in preventing and controlling such pathogens. This study aimed to investigate the antimicrobial activity and mechanism of a novel hydrogen peroxide and silver (H 2 O 2 -Ag + ) complex (HSC) in combatting Staphylococcus aureus ATCC 29213, Escherichia coli O157:H7 NCTC 12900 and Salmonella typhimurium SL 1344. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values against S. aureus were found to be 0.014 % H 2 O 2 -3.125 mg/L Ag + , while 0.028 % H 2 O 2 -6.25 mg/L Ag + for both E. coli and S. typhimurium . Results of the growth curve assay and time-kill trial suggest that the HSC could inhibit the growth of the tested bacteria, as 99.9 % of viable cells were killed following treatment at the 1 MIC for 3 h. Compared with Oxytech D10 disinfectant (0.25 % H 2 O 2 -5 mg/L Ag + ), the HSC exhibited better antibacterial efficacy at a lower concentration (0.045 % H 2 O 2 -10 mg/L Ag + ). The mechanism of antibacterial action of HSC was found including the disruption of the bacterial cell membrane, followed by entry into the bacteria cell to reduce intracellular adenosine triphosphate (ATP) concentration, and inhibit the activity of antioxidases, superoxide dismutase (SOD) and catalase (CAT). The enhanced bactericidal effect of hydrogen peroxide combined with silver indicates a potential for its application in environmental disinfection, particularly in the food industry.

Food Poisoning Potential of Artificially Contaminated Vacuum Packaged Sliced Ham in Sandwiches1

1981 ◽  
Vol 44 (6) ◽  
pp. 430-434 ◽  
Author(s):  
JAMES E. STEELE ◽  
MICHAEL E. STILES
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Storage Temperature ◽  
Food Poisoning ◽  
Microbial Competition ◽  
Growth And Survival ◽  
E Coli ◽  
Enteropathogenic Bacteria ◽  
Test Conditions ◽  
And Staphylococcus Aureus

Ham sandwiches inoculated with a mixture of five enteropathogenic bacteria, Bacillus cereus, Clostridium perfringens. Escherichia coli, Salmonella typhimurium and Staphylococcus aureus, were held at 30, 21 and 4 C for up to 24 h. Food poisoning potential was judged by the growth and survival of the inoculated pathogens. Major differences were observed between new and old (30 days of storage at 4 C) ham samples. On new ham, all enteropathogens were able to grow except C. perfringens, whereas on old ham, with high microbial competition. the pathogens survived but did not grow. Severe storage temperature abuse was necessary to develop a food poisoning potential in new ham samples. The safety of old ham was attributed to the competitive microflora that grew in the ham during storage at 4 C for 30 days. Infective pathogens, E. coli and S. typhimurium, either survived or increased in numbers under all test conditions. The safety of vacuum packaged sliced ham for use in sandwiches, in its present market form, was indicated by these studies.

Fate of Pathogens Inoculated onto Vacuum-Packaged Sliced Hams to Simulate Contamination During Packaging1

1979 ◽  
Vol 42 (6) ◽  
pp. 464-469 ◽  
Author(s):  
M. E. STILES ◽  
L.-K. NG
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Salmonella Typhimurium ◽  
Bacillus Cereus ◽  
Clostridium Perfringens ◽  
Subsequent Treatment ◽  
Vacuum Packaging ◽  
E Coli ◽  
Survival And Growth ◽  
And Staphylococcus Aureus

Ham and chopped ham from two manufacturers were contaminated with five enteropathogens: Bacillus cereus, Clostridium perfringens, Escherichia coli, Salmonella typhimurium and Staphylococcus aureus, at time of slicing and vacuum-packaging, to simulate contamination by manufacturer. Subsequent treatment of the samples, representing sound and undesirable retail handling and consumer use conditions, indicated marked differences in the fate of the pathogens between these products and within product type between the two manufacturers. Greatest differences were observed between the chopped ham products. All pathogens, except C. perfringens, grew actively in fresh ham and chopped ham with abusive holding at 30 and 21 C. After storage at 4 or 10 C for 30 days, B. cereus and C. perfringens were no longer detected, even after subsequent holding at 30 or 21 C for 24 h. E. coli survival and growth was variable, S. typhimurium survived well and grew under some conditions and S. aureus was generally inhibited at high levels of competition.

scholarly journals Enterosin KP’nin Antibakteriyal Aktivitesi Üzerine Para-Hidroksi-Benzoik Asit ile Propil-Parabenin Sinerjit Etkisi

2014 ◽  
Vol 2 (1) ◽  
pp. 1 ◽  
Author(s):  
Zeliha Yıldırım ◽  
Yaselin İlk ◽  
Metin Yıldırım
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Salmonella Typhimurium ◽  
Inhibitory Activity ◽  
Hydroxybenzoic Acid ◽  
Escherichia Coli O157 ◽  
Food Preservatives ◽  
Food Preservative ◽  
E Coli ◽  
Propyl Paraben

In this study, the effects of food preservative p-hydroxybenzoic acid and propyl-paraben on the inhibitory activity of enterocin KP produced by Enterococcus faecalis KP were determined. Staphylococcus aureus, Escherichia coli O157:H7 and Salmonella Typhimurium, resistant to enterocin KP bacteriocin, were used as target organisms. The inhibitor activity of enterosin KP (1600 AU/ml) alone or in combination with p-hydroxybenzoic acid (%0.1-0.3) and propyl-paraben (%0.008-0.16) on the growth of Staphylococcus aureus, Escherichia coli O157:H7 and Salmonella Typhimurium were determined. The inhibitory activity of enterocin KP was increased when used in combination with p-hydroxybenzoic acid and propyl-paraben at concentrations of 0.1-0.3% and 0.008-0.016%, respectively. Furthermore, Staphylococcus aureus, E. coli O157:H7 and Salmonella Typhimurium became sensitive to enterocin KP. In conclusion, the use of enterocin KP in combination with other food preservatives principles resulted in an increase in its inhibitory activity and spectrum.

Inhibition and Inactivation of Five Species of Foodborne Pathogens by Chitosan

1992 ◽  
Vol 55 (11) ◽  
pp. 916-919 ◽  
Author(s):  
GUANG-HUA WANG
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Antibacterial Activity ◽  
Acetic Acid ◽  
Listeria Monocytogenes ◽  
Salmonella Typhimurium ◽  
Yersinia Enterocolitica ◽  
Foodborne Pathogens ◽  
E Coli ◽  
No Inhibition

Inhibition and inactivation of five species of foodborne pathogens (Staphylococcus aureus, Escherichia coli, Yersinia enterocolitica, Listeria monocytogenes, and Salmonella typhimurium) by chitosan were studied. Nutrient broths were supplemented with 0, 0.5, 1.0, 1.5, 2.0, and 2.5% chitosan, adjusted to pH 6.5 or 5.5 with 2% acetic acid, and incubated at 30°C. The outgrowths of these bacteria were observed. At pH 6.5, in general, antibacterial activity of chitosan was relatively weak. The effectiveness of chitosan against S. aureus was greatest, followed by S. typhimurium, E. coli, and Y. enterocolitica. As the concentration of chitosan increased, the effectiveness of chitosan against these four species of pathogens also increased. No inhibition of L. monocytogenes by chitosan occurred. At pH 5.5, presence of chitosan inactivated these pathogens except that 0.5% chitosan did not affect the growth of S. typhimurium. Thus, the antibacterial activity of chitosan was stronger at pH 5.5 than at pH 6.5.

Growth and Survival of Foodborne Pathogens in Beer

2011 ◽  
Vol 74 (10) ◽  
pp. 1670-1675 ◽  
Author(s):  
GARRY MENZ ◽  
PETER ALDRED ◽  
FRANK VRIESEKOOP
Keyword(s):  
Salmonella Typhimurium ◽  
Foodborne Pathogens ◽  
Storage Temperature ◽  
Escherichia Coli O157 ◽  
Gram Negative ◽  
Growth And Survival ◽  
E Coli ◽  
And Storage ◽  
And Staphylococcus Aureus ◽  
Storage Temperatures

This work aimed to assess the growth and survival of four foodborne pathogens (Escherichia coli O157:H7, Salmonella Typhimurium, Listeria monocytogenes, and Staphylococcus aureus) in beer. The effects of ethanol, pH, and storage temperature were investigated for the gram-negative pathogens (E. coli O157:H7 and Salmonella Typhimurium), whereas the presence of hops ensured that the gram-positive pathogens (L. monocytogenes and S. aureus) were rapidly inactivated in alcohol-free beer. The pathogens E. coli O157:H7 and Salmonella Typhimurium could not grow in the mid-strength or full-strength beers, although they could survive for more than 30 days in the mid-strength beer when held at 4°C. These pathogens grew rapidly in the alcohol-free beer; however, growth was prevented when the pH of the alcohol-free beer was lowered from the “as received” value of 4.3 to 4.0. Pathogen survival in all beers was prolonged at lowered storage temperatures.

scholarly journals Comportamiento de microorganismos patogenos en salsa de xoconostle (Opuntia oligacantha f. C. Först)

2015 ◽  
Vol 1 (2) ◽  
Author(s):  
L.R. Rodarte-Medina ◽  
A.D. Hernández-Fuentes ◽  
J. Castro-Rosas ◽  
C.A. Gómez-Aldapa
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Listeria Monocytogenes ◽  
Salmonella Typhimurium ◽  
Escherichia Coli O157 ◽  
E Coli

Se investigó el comportamiento de Escherichia coli O157:H7, Listeria monocytogenes, Staphylococcus aureus y Salmonella Typhimurium, en salsa con y sin Xoconostle (Opuntia oligacantha F. C. Först). Los frutos se recolectaron directamente de un huerto de Xoconostle y se trasportaron al laboratorio a temperatura ambiente. En el laboratorio se prepararon 3 tipos de salsa con tres formulaciones teniendo como base principal: chile-Xoconostle (A), Chile-Xoconostle-Jitomate (B) y Chile-Jitomate (C). Por separado, las bacterias patógenas fueron inoculadas en las salsas y éstas se almacenaron a 3-5° y 30° C. El recuento de los microorganismos patógenos se realizó mediante la técnica de vertido en placa. Además, se evaluó el efecto antimicrobiano de las salsas de Xoconostle, del fruto de Xoconostle y del chile mediante la técnica de difusión en agar. Tanto E. coli O157:H7 como S. aureus se multiplicaron en la salsa. L. monocytogenes y S. Typhimurium no mostraron desarrollo. En todos los casos la salsa tipo A presento mayor efecto inhibitorio en el desarrollo de E. coli y S. aureus, o en la sobrevivencia de L. monocytogenes y S. Typhimurium. Mediante la técnica de difusión en placa se observó que tanto el Xoconostle como las salsas a base de Xoconostle mostraron efecto antimicrobiano. El chile no mostró efecto antimicrobiano.

Efficiency of Sodium Hypochlorite, Fumaric Acid, and Mild Heat in Killing Native Microflora and Escherichia coli O157:H7, Salmonella Typhimurium DT104, and Staphylococcus aureus Attached to Fresh-Cut Lettuce

2006 ◽  
Vol 69 (2) ◽  
pp. 323-329 ◽  
Author(s):  
NOZOMI KONDO ◽  
MASATSUNE MURATA ◽  
KENJI ISSHIKI
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Salmonella Typhimurium ◽  
Sodium Hypochlorite ◽  
Fumaric Acid ◽  
Bacterial Flora ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Mild Heat ◽  
Log Reduction

The effect of the disinfectant sodium hypochlorite (NaClO), with or without mild heat (50°C) and fumaric acid, on native bacteria and the foodborne pathogens Staphylococcus aureus, Escherichia coli O157:H7, and Salmonella Typhimurium DT104 attached to iceberg lettuce leaves was examined. The retail lettuce examined consistently harbored 6 to 7 log CFU/g of native bacteria throughout the study period. Inner leaves supported 1 to 2 log CFU/g fewer bacteria than outer leaves. About 70% of the native bacterial flora was removed by washing five times with 0.85% NaCl. S. aureus, E. coli, and Salmonella allowed to attach to lettuce leaves for 5 min were more easily removed by washing than when allowed to attach for 1 h or 2 days, with more S. aureus being removed than E. coli or Salmonella Typhimurium. An increase of time for attachment of pathogens from 5 min to 2 days leads to decreased efficiency of the washing and sanitizing treatment. Treatment with fumaric acid (50 mM for 10 min at room temperature) was the most effective, although it caused browning of the lettuce, with up to a 2-log reduction observed. The combination of 200 ppm of sodium hypochlorite and mild heat treatment at 50°C for 1 min reduced the pathogen populations by 94 to 98% (1.2- to 1.7-log reduction) without increasing browning.

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