Bactericidal effects of roselle (Hibiscus sabdariffa) against foodborne pathogens in vitro and on romaine lettuce and alfalfa sprouts

2011 ◽  
Vol 4 (1) ◽  
pp. 33-40 ◽  
Author(s):  
Divya Jaroni ◽  
Sadhana Ravishankar
2021 ◽  
Vol 9 (4) ◽  
pp. 860
Author(s):  
Gizem Levent ◽  
Robin C. Anderson ◽  
Branko Petrujkić ◽  
Toni L. Poole ◽  
Haiqi He ◽  
...  

The gut of food-producing animals is a reservoir for foodborne pathogens. Thymol is bactericidal against foodborne pathogens but rapid absorption of thymol from the proximal gut precludes the delivery of effective concentrations to the lower gut where pathogens mainly colonize. Thymol-β-d-glucopyranoside is reported to be more resistant to absorption than thymol in everted jejunal segments and could potentially function as a prebiotic by resisting degradation and absorption in the proximal gut but being hydrolysable by microbial β-glycosidase in the distal gut. Previous in vitro studies showed bactericidal effects of thymol-β-d-glucopyranoside against Campylobacter, Escherichia coli, and Salmonella enterica serovar Typhimurium in the presence but not absence of intestinal microbes expressing β-glycosidase activity, indicating that hydrolysis was required to obtain antimicrobial activity. Presently, the oral administration of thymol-β-d-glucopyranoside was studied to examine the effects on intestinal carriage of Campylobacter, E. coli, and S. Typhimurium in swine. The effects of thymol-β-d-glucopyranoside or thymol on antimicrobial sensitivity of representative E. coli isolates and characterized Salmonella strains were also explored. Results from two in vivo studies revealed little antimicrobial effects of thymol-β-d-glucopyranoside on Campylobacter, E. coli, or S. Typhimurium in swine gut. These findings add credence to current thinking that hydrolysis and absorption of thymol-β-d-glucopyranoside and thymol may be sufficiently rapid within the proximal gut to preclude delivery to the distal gut. Antibiotic susceptibilities of selected bacterial isolates and strains were mainly unaffected by thymol. Further research is warranted to overcome obstacles, preventing the delivery of efficacious amounts of thymol-β-d-glucopyranoside to the lower gut.


2010 ◽  
Vol 73 (3) ◽  
pp. 556-561 ◽  
Author(s):  
JI-HYOUNG HA ◽  
SANG-DO HA

The purpose of this study was to determine whether combined treatments would produce synergistic disinfection effects on food products during food processing compared with single treatments. We investigated the bactericidal effects of a commercial chemical disinfectant (ethanol) and of UV radiation on Bacillus cereus F4810/72, Cronobacter sakazakii KCTC 2949, Staphylococcus aureus ATCC 35556, Escherichia coli ATCC 10536, and Salmonella enterica Typhimurium NO/NA in vitro. Various concentrations of ethanol (10, 30, 40, and 50%) were tested with various exposure doses of UV radiation (6, 96, 216, 360, and 504 mWs/cm2) with a UV lamp. The combined ethanol-UV treatments resulted in greater reductions in bacterial counts than did either treatment alone. The synergistic effect values for B. cereus, C. sakazakii, S. aureus, S. enterica Typhimurium NO/NA, and E. coli were 0.40 to 1.52, 0.52 to 1.74, 0.20 to 2.32, 0.07 to 1.14, and 0.02 to 1.75 log CFU/ml, respectively. The results of this study suggest that a significant synergistic benefit results from combining ethanol and UV treatments against foodborne pathogens in vitro.


2021 ◽  
Vol 84 (7) ◽  
pp. 1127-1135
Author(s):  
LUIS ENRIQUE ORTIZ-SUÁREZ ◽  
MAURICIO REDONDO-SOLANO ◽  
MARÍA LAURA ARIAS-ECHANDI ◽  
CAROL VALENZUELA-MARTÍNEZ ◽  
ETNA AIDA PEÑA-RAMOS

ABSTRACT Campylobacter spp. and Arcobacter butzleri are foodborne pathogens associated with the consumption of contaminated raw chicken meat. At the industry level, the combination of new and common antimicrobials could be used as a strategy to control the presence of pathogens in chicken carcasses. The objective of this study was to determine the bacteriostatic and bactericidal effects of a mixture of chlorine (Cl) and sodium gallate (SG) on a mixture of two Campylobacter species (Campylobacter jejuni and Campylobacter coli) and A. butzleri. Using a central composite experimental design, it was established that the optimum inhibitory SG-Cl concentration for Campylobacter spp. was 44 to 45 ppm. After 15 h of incubation, Campylobacter species growth was reduced by 37.5% and the effect of Cl was potentiated by SG at concentrations above 45 ppm. In the case of A. butzleri, optimum levels of 28 and 41 ppm were observed for SG and Cl, respectively; no synergism was reported, as this bacterium was more sensitive to lower Cl concentrations than Campylobacter. After a 20-min pretreatment with peracetic acid (50 ppm), the optimum condition to achieve a >1.0-Log CFU/mL reduction of Campylobacter spp. was exposure to 177 ppm of Cl and 44 ppm of SG for 56 min. As A. butzleri showed lower resistance to the bacteriostatic effect of the Cl-SG combination, it was assumed that optimum bactericidal conditions for Campylobacter spp. were effective to control the former; this was confirmed with subsequent validation of the model. The SG-Cl combination has bactericidal properties against Campylobacter and A. butzleri, and it may be a useful strategy to improve sanitary practices applied in the poultry industry. HIGHLIGHTS


1985 ◽  
Vol 15 (suppl A) ◽  
pp. 227-232 ◽  
Author(s):  
A. R. White ◽  
D. H. Stokes ◽  
B. Slocombe ◽  
R. Sutherland

2011 ◽  
Vol 2011 ◽  
pp. 1-6 ◽  
Author(s):  
Masato Nagayoshi ◽  
Tatsuji Nishihara ◽  
Keisuke Nakashima ◽  
Shigetsugu Iwaki ◽  
Ker-Kong Chen ◽  
...  

Objective. Photodynamic therapy has been expanded for use in endodontic treatment. The aim of this study was to investigate the antimicrobial effects of diode laser irradiation on endodontic pathogens in periapical lesions using an in vitro apical lesion model. Study Design. Enterococcus faecalis in 0.5% semisolid agar with a photosensitizer was injected into apical lesion area of in vitro apical lesion model. The direct effects of irradiation with a diode laser as well as heat produced by irradiation on the viability of microorganisms in the lesions were analyzed. Results. The viability of E. faecalis was significantly reduced by the combination of a photosensitizer and laser irradiation. The temperature caused by irradiation rose, however, there were no cytotoxic effects of heat on the viability of E. faecalis. Conclusion. Our results suggest that utilization of a diode laser in combination with a photosensitizer may be useful for clinical treatment of periapical lesions.


2020 ◽  
Vol 11 (2) ◽  
pp. 8716-8724

In order to shed light on contamination risks along the ready-to-eat chain of fresh commodities by emerging foodborne pathogens, we investigated the biofilm development in vitro of two Pseudomonas aeruginosa strains on fresh-cut lettuce (Lactuca sativa L. var. Iceberg). The experiment was performed employing a floating bioreactor system where modified atmosphere package conditions were mimicked, and fresh-cut lettuce disks of 2 cm2 were put into contact with a 106 CFU/mL of a phenotypic mucoid P. aeruginosa phenotype (muc+) or a non-mucoid one (muc-). Following a simulated 2-day refrigerated-shelf quantitative Real-Time PCR, designed on a target gene region of the 16S rRNA gene, defined the different muc phenotypes behavior on biofilm in lettuce phyllo-plane. Between the two strains, a development difference of nearly 1.0 log CFU/cm2 occurred, with the muc+ phenotype being the most settled and adherent. This result clearly showed a distinct contamination risk according to P. aeruginosa phenotype and the need to develop real-time, specific, fast, and easy to use detection protocols along with specific sanitation systems for modified atmosphere package ready-to-eat commodities.


2020 ◽  
Vol 45 (2) ◽  
pp. 331-341
Author(s):  
F. T. Ajayi ◽  
S. O. Omotoso ◽  
O. J. Babayemi

Acetone and ethanol extracts of Albizia saman (ASL) and Tithonia diversifolia (TDL) leaves used as fodder for ruminant were evaluated for their antibacterial properties against selected pathogenic bacteria. Phytochemical screening was determined according to standard procedures, while antibacterial activity was by agar well diffusion and broth micro dilution methods. The levels of tannin (0.29 and 0.34 mg/100g); saponin (0.75 and 0.59 mg/100g); oxalates (0.17 and 0.14mg/100g); and phytate (0.11 and 0.12 mg/100g) in the fodder plants were below critical levels that may affect digestibility in ruminants. Acetone and ethanol extracts from ASL and TDL showed maximum zones of inhibition against Staphylococcus aureus (19.00 and 14.50 mm; 23.00 and 21.50 mm) and Pseudomonas aeruginosa (15.50 and 12.00 mm; 18.50 and 17.00 mm), respectively compared to Gentamycin (9.97 mm). Minimum inhibitory concentration (MIC) values of acetone and ethanol extracts from ASL ranged from 0.10 to 0.28 mg/mL and 0.13 to 0.22 mg/mL, while TDL extracts ranged from 0.20 to 0.32 mg/mL and 0.20 to 0.31 mg/mL, respectively for all the tested organisms. Minimum bactericidal concentration (MBC) values of ethanol extracts from both plant ranged from 0.5-0.80 mg/mL and 0.7-0.90 mg/mL compared to MBC values (0.02-0.04 mg/mL) of the reference antibiotic (gentamycin) for all the tested bacteria species. In conclusion, antibacterial properties exhibited by the plant extract implied that the bioactive compounds are potential antibacterial agents against pathogenic bacteria of ruminant or foodborne pathogens in vitro.


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